Internet Engineering Task Force (IETF)                       K. Moriarty
Request for Comments: 6545                                           EMC
Obsoletes: 6045                                               April 2012
Category: Standards Track
ISSN: 2070-1721


                Real-time Inter-network Defense (RID)

Abstract

  Security incidents, such as system compromises, worms, viruses,
  phishing incidents, and denial of service, typically result in the
  loss of service, data, and resources both human and system.  Service
  providers and Computer Security Incident Response Teams need to be
  equipped and ready to assist in communicating and tracing security
  incidents with tools and procedures in place before the occurrence of
  an attack.  Real-time Inter-network Defense (RID) outlines a
  proactive inter-network communication method to facilitate sharing
  incident-handling data while integrating existing detection, tracing,
  source identification, and mitigation mechanisms for a complete
  incident-handling solution.  Combining these capabilities in a
  communication system provides a way to achieve higher security levels
  on networks.  Policy guidelines for handling incidents are
  recommended and can be agreed upon by a consortium using the security
  recommendations and considerations.  This document obsoletes RFC
  6045.

Status of This Memo

  This is an Internet Standards Track document.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Further information on
  Internet Standards is available in Section 2 of RFC 5741.

  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  http://www.rfc-editor.org/info/rfc6545.










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Copyright Notice

  Copyright (c) 2012 IETF Trust and the persons identified as the
  document authors.  All rights reserved.

  This document is subject to BCP 78 and the IETF Trust's Legal
  Provisions Relating to IETF Documents
  (http://trustee.ietf.org/license-info) in effect on the date of
  publication of this document.  Please review these documents
  carefully, as they describe your rights and restrictions with respect
  to this document.  Code Components extracted from this document must
  include Simplified BSD License text as described in Section 4.e of
  the Trust Legal Provisions and are provided without warranty as
  described in the Simplified BSD License.

Table of Contents

  1. Introduction ....................................................3
     1.1. Changes from RFC 6045 ......................................5
     1.2. Normative and Informative ..................................6
     1.3. Terminology ................................................7
  2. Characteristics of Incidents ....................................7
  3. Communication between CSIRTs and Service Providers ..............8
     3.1. Inter-Service-Provider RID Messaging ......................10
     3.2. RID Communication Topology ................................12
  4. Message Formats ................................................13
     4.1. RID Data Types ............................................13
          4.1.1. Boolean ............................................13
     4.2. RID Message Types .........................................14
  5. IODEF-RID Schema ...............................................15
     5.1. RIDPolicy Class ...........................................17
          5.1.1. ReportSchema .......................................23
     5.2. RequestStatus .............................................26
     5.3. IncidentSource ............................................28
     5.4. RID Name Spaces ...........................................29
     5.5. Encoding ..................................................29
     5.6. Including IODEF or Other XML Documents ....................29
          5.6.1. Including XML Documents in RID .....................30
  6. RID Messages ...................................................31
     6.1. Request ...................................................31
     6.2. Acknowledgement ...........................................33
     6.3. Result ....................................................34
     6.4. Report ....................................................36
     6.5. Query .....................................................38
  7. RID Communication Exchanges ....................................39
     7.1. Upstream Trace Communication Flow .........................40
          7.1.1. RID TraceRequest Example ...........................43
          7.1.2. Acknowledgement Message Example ....................47



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          7.1.3. Result Message Example .............................47
     7.2. Investigation Request Communication Flow ..................50
          7.2.1. Investigation Request Example ......................51
          7.2.2. Acknowledgement Message Example ....................53
     7.3. Report Communication Flow .................................54
          7.3.1. Report Example .....................................54
     7.4. Query Communication Flow ..................................56
          7.4.1. Query Example ......................................57
  8. RID Schema Definition ..........................................58
  9. Security Requirements ..........................................62
     9.1. XML Digital Signatures and Encryption .....................62
     9.2. Message Transport .........................................66
     9.3. Public Key Infrastructure .................................67
          9.3.1. Authentication .....................................68
          9.3.2. Multi-Hop Request Authentication ...................69
     9.4. Consortiums and Public Key Infrastructures ................70
     9.5. Privacy Concerns and System Use Guidelines ................71
     9.6. Sharing Profiles and Policies .............................76
  10. Security Considerations .......................................77
  11. Internationalization Issues ...................................77
  12. IANA Considerations ...........................................78
  13. Summary .......................................................80
  14. References ....................................................80
     14.1. Normative References .....................................80
     14.2. Informative References ...................................82
  Appendix A. Acknowledgements ......................................84

1.  Introduction

  Organizations require help from other parties to identify incidents,
  mitigate malicious activity targeting their computing resources, and
  to gain insight into potential threats through the sharing of
  information.  This coordination might entail working with a service
  provider (SP) to filter attack traffic, working with an SP to resolve
  a configuration issue that is unintentionally causing problems,
  contacting a remote site to take down a bot network, or sharing
  watch-lists of known malicious IP addresses in a consortium.  The
  term "SP" is to be interpreted as any type of service provider or
  Computer Security Incident Response Team (CSIRT) that may be involved
  in RID communications.

  Incident handling involves the detection, reporting, identification,
  and mitigation of an incident, whether it be a benign configuration
  issue, IT incident, an infraction to a service level agreement (SLA),
  system compromise, socially engineered phishing attack, or a denial-
  of-service (DoS) attack, etc.  When an incident is detected, the
  response may include simply filing a report, notification to the
  source of the incident, a request to an SP for resolution/mitigation,



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  or a request to locate the source.  One of the more difficult cases
  is that in which the source of an attack is unknown, requiring the
  ability to trace the attack traffic iteratively upstream through the
  network for the possibility of any further actions to take place.  In
  cases when accurate records of an active session between the target
  or victim system and the source or attacking system are available,
  the source is easy to identify.

  Real-time inter-network defense (RID) outlines a proactive inter-
  network communication method to facilitate sharing incident-handling
  data while integrating existing detection, tracing, source
  identification, and mitigation mechanisms for a complete incident
  handling solution.  RID provides a secure method to communicate
  incident information, enabling the exchange of Incident Object
  Description and Exchange Format (IODEF) [RFC5070] Extensible Markup
  Language (XML) documents.  RID considers security, policy, and
  privacy issues related to the exchange of potentially sensitive
  information, enabling SPs or organizations the options to make
  appropriate decisions according to their policies.  RID includes
  provisions for confidentiality, integrity, and authentication.

  The data in RID messages is represented in an XML [XML1.0] document
  using the IODEF and RID.  By following this model, integration with
  other aspects for incident handling is simplified.  Methods are
  incorporated into the communication system to indicate what actions
  need to be taken closest to the source in order to halt or mitigate
  the effects of the incident or attack at hand.  RID is intended to
  provide a method to communicate the relevant information between
  CSIRTs while being compatible with a variety of existing and possible
  future detection-tracing and response approaches.  Incidents may be
  extended to include Information Technology (IT) incidents, where RID
  enables the communication between or within providers for non-
  security IT incidents.

  Security and privacy considerations are of high concern since
  potentially sensitive information may be passed through RID messages.
  RID messaging takes advantage of XML security, privacy, and policy
  information set in the RID schema.  The RID schema defines
  communication-specific metadata to support the communication of IODEF
  documents for exchanging or tracing information regarding incidents.
  RID messages are encapsulated for transport, which is defined in a
  separate document [RFC6546].  The authentication, integrity, and
  authorization features that RID and RID transport offer are used to
  achieve a necessary level of security.

  Coordinating with other CSIRTs is not strictly a technical problem.
  There are numerous procedural, trust, and legal considerations that
  might prevent an organization from sharing information.  RID provides



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  information and options that can be used by organizations who must
  then apply their own policies for sharing information.  Organizations
  must develop policies and procedures for the use of the RID protocol
  and IODEF.

1.1.  Changes from RFC 6045

  This document contains the following changes with respect to its
  predecessor [RFC6045]:

  o  This document is Standards Track, while [RFC6045] was published as
     Informational.

  o  This document obsoletes [RFC6045] and moves it to Historic status.

  o  This document refers to the updated RID transport specification
     [RFC6546], where appropriate.

  o  Edits reflected in this updated version of RID are primarily
     improvements to the informational descriptions.  The descriptions
     have been updated to clarify that IODEF and RID can be used for
     all types of incidents and are not limited to network security
     incidents.  The language has been updated to change the focus from
     attacks to incidents, where appropriate.  The term "network
     provider" has been replaced with the more generic term of "service
     provider".  Several introductory informational sections have been
     removed as they are not necessary for the implementation of the
     protocol.  The sections include:

     *  1.3.  Attack Types and RID Messaging,

     *  2.  RID Integration with Network Provider Technologies,

     *  3.1.  Integrating Trace Approaches, and

     *  3.2.  Superset of Packet Information for Traces.

  o  An option for a star topology has been included in an
     informational section to meet current use-case requirements of
     those who provide reports on incident information.

  o  The schema version was incremented.  The schema has changed to
     include IODEF [RFC5070] enveloped in RID in the RIDPolicy class
     using the new ReportSchema class, to include one verified erratum,
     to include additional enumerations in the Justification attribute,
     to remove the AcrossNationalBoundaries region enumeration, to add
     the DataWithHandlingRequirements enumeration in TrafficTypes, and
     to change the name of the RequestAuthorization MsgType to



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     Acknowledgement.  Additional text has been provided to clarify
     definitions of enumerated values for some attributes.  The
     RequestAuthorization name was replaced with Acknowledgement to
     more accurately represent the function of that message type.  Text
     was clarified to note the possible use of this message in response
     to Query and Report messages.  The attributes were fixed in the
     schema to add 'lang' at the RID class level for language support.

  o  The TraceRequest and Investigation messages have been collapsed
     into a single message with the requirement to set the MsgType
     according to the functionality required for automation.  The
     message descriptions were identical with the exception of the
     MsgType, which remains an exception depending on the desired
     function.  Since both of the enumerations for MsgType are each a
     Request, 'Investigation' is now 'InvestigationRequest'.  Content
     may vary within the IODEF document for the type of Request
     specified.

  o  The IncidentQuery message description name and MsgType enumeration
     value in the schema have been changed to the more generic name of
     'Query'.

  o  Guidance has been improved to ensure consistent implementations
     and use of XML encryption to provide confidentiality based on data
     markers, specifically the iodef:restriction attribute in the IODEF
     and IODEF-RID schemas.  The attribute may also be present in IODEF
     extension schemas, where the guidance also applies.  Additional
     guidance and restrictions have been added for XML requirements.

  o  All of the normative text from the Security Considerations section
     has been moved to a new section, Security Requirements.

  o  The order in which the RID schema is presented in Section 5 has
     been changed to match the order in the IODEF-RID schema.

  o  Additional text has been provided to explain the content and
     interactions between entities in the examples.

  o  Additional references have been provided to improve
     interoperability with stricter guidance on the use of XML digital
     signatures and encryption.

1.2.  Normative and Informative

  Sections 1, 2, 3, and 12 provide helpful background information and
  considerations.  RID systems participating in a consortium are
  REQUIRED to fully implement Sections 4, 5, 6, 7, 8, 9, 10, and 11 to
  prevent interoperability concerns.



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1.3.  Terminology

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
  document are to be interpreted as described in [RFC2119].

2.  Characteristics of Incidents

  An incident may be defined as a benign configuration issue, IT
  incident, an infraction to a service level agreement (SLA), system
  compromise, a worm or Trojan infection, or a single- or multiple-
  source denial-of-service attack.  The goal of tracing a security
  incident may be to identify the source or to find a point on the
  network as close to the origin of the incident as possible.  Incident
  tracing can be used to identify the source(s) of an attack in order
  to halt or mitigate the undesired behavior or to correct an
  identified issue.  RID messages can be communicated between entities
  to report or investigate any type of incident and allow for actions
  to be taken when the source of the incident or a point closer to the
  source is known or has been identified.  Methods to accomplish
  mitigation may include remediation of a configuration issue,
  filtering or rate-limiting the traffic close to the source, or taking
  the host or network offline.  Care must also be taken to ensure that
  the systems involved in the RID communications are not abused and to
  use proper analysis in determining if attack traffic is, in fact,
  attack traffic at each SP involved in the investigation.

  Investigating security incidents can be a difficult task since
  attackers go to great lengths to obscure their identity.  In the case
  of a security incident, the true source might be identified through
  an existing established connection to the attacker's point of origin.
  However, the attacker may not connect to the compromised system for a
  long period of time after the initial compromise or may access the
  system through a series of compromised hosts spread across the
  network.  Other methods of obscuring the source may include targeting
  the host with the same attack from multiple sources using both valid
  and spoofed source addresses.  This tactic can be used to compromise
  a machine and leave the difficult task of locating the true origin
  for the administrators.  Attackers use many techniques, which can
  vary between individuals or even organized groups of attackers.
  Through analysis, the techniques may be grouped into indicators of
  compromise to be shared via IODEF and RID, further assisting with the
  improvement of detection capabilities.  Security incidents, including
  distributed denial-of-service (DDoS) attacks, can be difficult or
  nearly impossible to trace because of the nature of the attack.  Some
  of the difficulties in investigating attacks include the following:

  o  the incident or attack originates from multiple sources;



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  o  the incident may leverage social-engineering techniques or other
     methods to gain access to resources and intellectual property
     using what appears to be legitimate access methods such as
     outbound web sessions from user systems;

  o  the attack may include various types of traffic meant to consume
     server resources, such as a SYN flood attack without a significant
     increase in bandwidth utilization;

  o  the type of traffic could include valid destination services,
     which cannot be blocked since they are essential services to
     business, such as DNS servers at an SP or HTTP requests sent to an
     organization connected to the Internet;

  o  the attack may utilize varying types of packets including TCP,
     UDP, ICMP, or other IP protocols;

  o  the attack may be from "zombies" or large botnets, which then
     require additional searches to locate a controlling server as the
     true origin of the attack;

  o  the attack may use a very small number of packets from any
     particular source, thus making a trace after the fact nearly
     impossible;

  o  the indicators of a compromise may be difficult to detect.

  If the source(s) of an incident cannot be determined from IP address
  information, it may be possible to trace the traffic based on
  characteristics of the incident such as tracing the increased
  bandwidth utilization or the type of packets seen by the client.  In
  the case of packets with spoofed source addresses, it is not a
  trivial task to identify the source of an attack.

  IODEF, any extensions to IODEF, and RID can be used to detail an
  incident, characteristics of the incident (as it evolves), the
  incident history, and communications of the incident to facilitate
  the resolution and reporting of the incident.

3.  Communication between CSIRTs and Service Providers

  Expediting the communication between CSIRTs and SPs is essential when
  responding to a security-related incident, which may cross network
  access points between service providers.  As a result of the urgency
  involved in this inter-service-provider security incident
  communication, there must be an effective system in place to
  facilitate the interaction.  This communication policy or method
  should involve multiple means of communication to avoid a single



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  point of failure.  Email is one way to transfer information about the
  incident, packet traces, etc.  However, email may not be received in
  a timely fashion or be acted upon with the same urgency as a phone
  call or other communication mechanism like RID.

  A technical solution to trace traffic across a single SP may include
  homegrown or commercial systems for which RID messaging must
  accommodate the input requirements.  The incident-handling system
  used on the SP's backbone by the CSIRT to coordinate the trace across
  the single network requires a method to accept, process, and relay
  RID messages to the system, as well as to wait for responses from the
  system to continue the RID request process as appropriate.  In this
  scenario, each service provider maintains its own system capable of
  communicating via RID and integrates with a management station used
  for monitoring and analysis.  An alternative for providers lacking
  sufficient resources may be to have a neutral third party with access
  to the provider's network resources who could be used to perform the
  incident-handling functions.  This could be a function of a central
  organization operating as a CSIRT for countries as a whole or within
  a consortium that may be able to provide centralized resources.

  Consortiums could consist of a federation or a group of service
  providers or CSIRTs that agrees to participate in the RID
  communication protocol with an agreed-upon policy and communication
  protocol facilitating the secure transport of IODEF-RID XML
  documents.  Transport for RID messages is specified in [RFC6546].

  One goal of RID is to prevent the need to permit access to other
  networks' equipment.  RID provides a standard messaging mechanism to
  enable the communication of incident-handling information to other
  providers in a consortium or in neighboring networks.  The third
  party mentioned above may be used in this technical solution to
  assist in facilitating incident handling and possibly traceback
  through smaller providers.  The RID messaging mechanism may be a
  logical or physical out-of-band network to ensure that the
  communication is secure and unaffected by the state of the network
  under attack.  The two management methods would accommodate the needs
  of larger providers to maintain full management of their network, and
  the third-party option could be available to smaller providers who
  lack the necessary human resources to perform incident-handling
  operations.  The first method enables the individual providers to
  involve (via a notification and alerting system) their network
  operations staff to authorize the continuance of a trace or other
  necessary response to a RID communication request through their
  network.






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  The network used for the communication should consist of out-of-band
  or protected channels (direct communication links) or encrypted
  channels dedicated to the transport of RID messages.  The
  communication links would be direct connections (virtual or physical)
  between peers who have agreed-upon use and abuse policies through a
  consortium.  Consortiums might be linked through policy comparisons
  and additional agreements to form a larger web or iterative network
  of peers that correlates to the traffic paths available over the
  larger web of networks or is based on regions and logical groups.
  Contact information, IP addresses of RID systems, and other
  information must be coordinated between bilateral peers by a
  consortium and may use existing databases, such as the routing
  arbiter.  The security, configuration, and Confidence rating schemes
  of the RID messaging peers must be negotiated by peers and must meet
  certain overall requirements of the fully connected network
  (Internet, government, education, etc.) through the peering and/or a
  consortium-based agreement.

  RID messaging established with clients of an provider may be
  negotiated in a contract as part of a value-added service or through
  a service level agreement (SLA).  Further discussion is beyond the
  scope of this document and may be more appropriately handled in
  peering or service level agreements.

  Procedures for incident handling need to be established and well
  known by anyone that may be involved in incident response.  The
  procedures should also contain contact information for internal
  escalation procedures, as well as for external assistance groups such
  as a CSIRT, CERT Coordination Center (CERT/CC), Global Information
  Assurance Certification (GIAC), and the U.S. Federal Bureau of
  Investigations (FBI) or other assisting government organization in
  the country of the investigation.

3.1.  Inter-Service-Provider RID Messaging

  RID provides a protocol and format that ensures interoperability
  between vendors for the implementation of an incident messaging
  mechanism.  The messages should meet several requirements in order to
  be meaningful as they traverse multiple networks.  RID provides the
  framework necessary for communication between networks involved in
  the incident handling, possible traceback, and mitigation of a
  security incident.  Several message types described in Section 4.2
  are necessary to facilitate the handling of a security incident.  The
  message types include the Report, Query, Request, Acknowledgement,
  and Result message.

  The Report message is used when an incident is to be filed on a RID
  system or associated database, where no further action is required.



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  A Query message is used to request information on a particular
  incident.  A Request message with options set to 'TraceRequest' is
  used when the source of the traffic may have been spoofed.  In that
  case, each SP in the upstream path who receives this Request will
  issue a trace across the network to determine the upstream source of
  the traffic.  The Acknowledgement and Result messages are used to
  communicate the status and result of a Request.  The Request message
  with options set to 'InvestigationRequest' may be sent to any party
  assisting in an incident investigation.  The InvestigationRequest
  leverages the bilateral relationships or a consortium's
  interconnections to mitigate or stop problematic traffic close to the
  source.  Routes could determine the fastest path to a known source IP
  address in the case of an InvestigationRequest.  A Request message
  (set to 'TraceRequest' or 'InvestigationRequest') sent between RID
  systems to stop traffic at the source through a bordering network
  requires the information enumerated below:

  1.  Enough information to enable the network administrators to make a
      decision about the importance of continuing the trace.

  2.  The incident or IP packet information needed to carry out the
      trace or investigation.

  3.  Contact information of the origin of the RID communication.  The
      contact information could be provided through the Autonomous
      System Number (ASN) [RFC1930] or Network Information Center (NIC)
      handle information listed in the Registry for Internet Numbers or
      other Internet databases.

  4.  Network path information to help prevent any routing loops
      through the network from perpetuating a trace.  If a RID system
      receives a Request with MsgType set to 'TraceRequest' that
      contains its own information in the path, the trace must cease
      and the RID system should generate an alert to inform the network
      operations staff that a tracing loop exists.

  5.  A unique identifier for a single attack.  This identifier should
      be used to correlate traces to multiple sources in a DDoS attack.

  Use of the communication network and the RID protocol must be for
  pre-approved, authorized purposes only.  It is the responsibility of
  each participating party to adhere to guidelines set forth in both a
  global use policy established through the peering agreements for each
  bilateral peer or agreed-upon consortium guidelines.  The purpose of
  such policies is to avoid abuse of the system; the policies shall be
  developed by a consortium or participating entities.  The global
  policy may be dependent on the domain it operates under; for example,
  a government network or a commercial network such as the Internet



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  would adhere to different guidelines to address the individual
  concerns.  Privacy issues must be considered in public networks such
  as the Internet.  Privacy issues are discussed in the Security
  Requirements section, along with other requirements that must be
  agreed upon by participating entities.

  RID requests must be legitimate incidents and not used for purposes
  such as sabotage or censorship.  An example of such abuse of the
  system includes a request to rate-limit legitimate traffic to prevent
  information from being shared between users on the Internet
  (restricting access to online versions of papers) or restricting
  access from a competitor's product in order to sabotage a business.

  The RID system should be configurable to either require user input or
  automatically continue traces.  This feature enables a network
  manager to assess the available resources before continuing a Request
  message set to 'InvestigationRequest' or 'TraceRequest'.  If the
  Confidence rating (provided in IODEF) is low, it may not be in the
  provider's best interest to continue the Request with options set to
  'InvestigationRequest' or 'TraceRequest'.  The Confidence ratings
  must adhere to the specifications for selecting the percentage used
  to avoid abuse of the system.  Requests must be issued by authorized
  individuals from the initiating CSIRT, set forth in policy guidelines
  established through peering or a SLA.

3.2.  RID Communication Topology

  The most basic topology for communicating RID systems is a direct
  connection or a bilateral relationship as illustrated below.

           ___________                                  __________
           |         |                                  |        |
           |  RID    |__________-------------___________|  RID   |
           |_________|          | SP Border |           |________|
                                -------------

                     Figure 1: Direct Peer Topology

  Within the consortium model, several topologies might be agreed upon
  and used.  One would leverage bilateral network peering relationships
  of the members of the consortium.  The peers for RID would match that
  of routing peers, and the logical network borders would be used.
  This approach may be necessary for an iterative trace where the
  source is unknown.  The model looks like the above diagram; however,
  there may be an extensive number of interconnections of bilateral
  relationships formed.  Also within a consortium model, it may be
  useful to establish an integrated mesh of networks to pass RID
  messages.  This may be beneficial when the source address is known,



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  and an interconnection may provide a faster route to reach the
  closest upstream peer to the source of the attack traffic if direct
  communication between SPs is not possible.  An example is illustrated
  below.

      _______                     _______                     _______
      |     |                     |     |                     |     |
    __| RID |____-------------____| RID |____-------------____| RID |__
      |_____|    | SP Border |    |_____|    | SP Border |    |_____|
         |       -------------               -------------       |
         |_______________________________________________________|

     Direct connection to network that is not an immediate network peer

                      Figure 2: Mesh Peer Topology

  By using a fully meshed model in a consortium, broadcasting RID
  requests would be possible, but not advisable.  By broadcasting a
  request, RID peers that may not have carried the attack traffic on
  their network would be asked to perform a trace for the potential of
  decreasing the time in which the true source was identified.  As a
  result, many networks would have utilized unnecessary resources for a
  Request that may have also been unnecessary.

  A star topology may be desirable in instances where a peer may be a
  provider of incident information.  This requires trust relationships
  to be established between the provider of information and each of the
  consumers of that information.  Examples may include country-level
  CSIRTs or service providers distributing incident information to
  organizations.

4.  Message Formats

4.1.  RID Data Types

  RID is derived from the IODEF data model and inherits all of the data
  types defined in the IODEF model.  One data type is added by RID:
  BOOLEAN.

4.1.1.  Boolean

  A boolean value is represented by the BOOLEAN data type.

  The BOOLEAN data type is implemented as "xs:boolean" [XMLschema] in
  the schema.  Note that there are two lexical representations for
  boolean in [XMLschema]: '1' or 'true' for TRUE and '0' or 'false' or
  FALSE.




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4.2.  RID Message Types

  The five RID message types described below MUST be implemented.  RID
  messages uses both the IODEF [RFC5070] and RID document, which MUST
  be encapsulated for transport as specified in [RFC6546].  The
  messages are generated and received on designated systems for RID
  communications.  Each RID message type, along with an example, is
  described in the following sections.  The IODEF-RID schema is
  introduced in Section 5 to support the described RID message types.

  1.  Request.  This message type is used when a request
      ('InvestigationRequest' or 'TraceRequest') is needed.  The
      purpose of the Request message (set to 'InvestigationRequest') is
      to leverage the existing peer relationships in order to notify
      the SP closest to the source of the valid traffic of a security-
      related incident for any necessary actions to be taken.  The
      Request (set to 'TraceRequest') is used when the traffic has to
      be traced iteratively through networks to find the source by
      setting the MsgType to 'TraceRequest'.  The
      'InvestigationRequest' MsgType is used for all other Request
      messages.

  2.  Acknowledgement.  This message is sent to the initiating RID
      system from each of the upstream provider's RID systems to
      provide information on the status of a Request.  The
      Acknowledgement is also used to provide a reason why a Request,
      Report, or Query was not accepted.

  3.  Result.  The Result message is used to provide a final report and
      the notification of actions taken for a Request.  This message is
      sent to the initiating CSIRT through the network of RID systems
      in the path of the trace as notification that the source of the
      attack was located.

  4.  Report.  This message is used to report a security incident, for
      which no action is requested.  This may be used for the purpose
      of correlating attack information by CSIRTs, sharing incident
      information, statistics and trending information, etc.

  5.  Query.  This message is used to request information about an
      incident or incident type from a trusted system communicating via
      RID.  The response is provided through the Report message.

  When an application receives a RID message, it must be able to
  determine the type of message and parse it accordingly.  The message
  type is specified in the RIDPolicy class.  The RIDPolicy class may





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  also be used by the transport protocol to facilitate the
  communication of security incident data to trace, investigate, query,
  or report information regarding security incidents.

5.  IODEF-RID Schema

  There are three classes included in the RID extension required to
  facilitate RID communications.  The RequestStatus class is used to
  indicate the approval status of a Request message; the IncidentSource
  class is used to report whether or not a source was found and to
  identify the source host(s) or network(s); and the RIDPolicy class
  provides information on the agreed-upon policies and specifies the
  type of communication message being used.

  The RID schema defines communication-specific metadata to support the
  exchange of incident information in an IODEF document.  The intent in
  maintaining a separate schema and not using the AdditionalData
  extension of IODEF is the flexibility of sending messages between RID
  hosts.  Since RID is a separate schema and RID messages include both
  the RID and IODEF documents, the RID message acts as an envelope in
  that policy and security defined at the RID message layer are applied
  to both documents.  One reason for maintaining separate schemas is
  for flexibility, where the RIDPolicy class can be easily extracted
  for use in the RID message and by the transport protocol.

  The security requirements of sending incident information between
  entities include the use of encryption.  The RIDPolicy information is
  not required to be encrypted, so separating out this data from the
  IODEF XML document removes the need for decrypting and parsing the
  IODEF document to determine how it should be handled at each RID
  host.

  The purpose of the RIDPolicy class is to specify the message type for
  the receiving host, facilitate the policy needs of RID, and provide
  routing information in the form of an IP address of the destination
  RID system.

  The security requirements and policy guidelines are discussed in
  Section 9.  The policy is defined between RID peers and within or
  between consortiums.  RIDPolicy is meant to be a tool to facilitate
  the defined policies.  This MUST be used in accordance with policy
  set between clients, peers, consortiums, and/or regions.  Security,
  privacy, and confidentiality MUST be considered as specified in this
  document.







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  The RID schema is defined as follows:

          +------------------+
          |        RID       |
          +------------------+
          |                  |
          | ENUM lang        |<>---{0..1}----[ RIDPolicy      ]
          |                  |
          |                  |<>---{0..1}----[ RequestStatus  ]
          |                  |
          |                  |<>---{0..1}----[ IncidentSource ]
          +------------------+

                        Figure 3: The RID Schema

  The aggregate classes that constitute the RID schema in the iodef-rid
  namespace are as follows:

  RIDPolicy

     Zero or One.  The RIDPolicy class is used by all message types to
     facilitate policy agreements between peers, consortiums, or
     federations, as well as to properly route messages.

  RequestStatus

     Zero or One.  The RequestStatus class is used only in
     Acknowledgement messages.  The message reports back to the CSIRT
     or SP in the Acknowledgement message to provide status on a
     Request or if an error or problem occurs with the receipt or
     processing of a Report, Query, or Result message.

  IncidentSource

     Zero or One.  The IncidentSource class is used in the Result
     message only.  The IncidentSource provides the information on the
     identified source host or network of an attack trace or
     investigation.

  Each of the three listed classes may be the only class included in
  the RID class, hence the option for zero or one.  In some cases,
  RIDPolicy MAY be the only class in the RID definition when used by
  the transport protocol [RFC6546], as that information should be as
  small as possible and may not be encrypted.  The RequestStatus
  message MUST be able to stand alone without the need for an IODEF
  document to facilitate the communication, limiting the data
  transported to the required elements per [RFC6546].




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  The RID class has one attribute:

     lang

        One.  REQUIRED.  ENUM.  A valid language code per [RFC5646]
        constrained by the definition of "xs:language" inherited from
        [XML1.0].

5.1.  RIDPolicy Class

  The RIDPolicy class facilitates the delivery of RID messages and is
  also referenced for transport in the transport document [RFC6546].
  The RIDPolicy Class includes the ability to embed an IODEF document
  or XML documents that conform to schemas other than IODEF in the
  ReportSchema element.

         +------------------------+
         | RIDPolicy              |
         +------------------------+
         |                        |
         | ENUM restriction       |<>-------------[ Node         ]
         | ENUM MsgType           |
         | ENUM MsgDestination    |<>---{0..1}----[ IncidentID   ]
         | ENUM ext-MsgType       |
         | ENUM ext-MsgDestination|<>---{1..*}----[ PolicyRegion ]
         |                        |
         |                        |<>---{1..*}----[ TrafficType  ]
         |                        |
         |                        |<>---{0..1}----[ ReportSchema ]
         +------------------------+

                      Figure 4: The RIDPolicy Class

  The aggregate elements that constitute the RIDPolicy class are as
  follows:

  Node

     One.  The Node class is used to identify a host or network device,
     in this case to identify the system communicating RID messages,
     and the usage is determined by the MsgDestination attribute.  The
     base definition of this class is reused from the IODEF
     specification [RFC5070], Section 3.16.  See Section 11 of this
     document for Internationalization considerations.







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  IncidentID

     Zero or one.  Global reference pointing back to the IncidentID
     defined in the IODEF data model.  The IncidentID includes the name
     of the CSIRT, an incident number, and an instance of that
     incident.  The instance number is appended with a dash separating
     the values and is used in cases for which it may be desirable to
     group incidents.  Examples of incidents that may be grouped
     include botnets, polymorphic attacks, DDoS attacks, multiple hops
     of compromised systems found during an investigation, etc.

  PolicyRegion

     One or many.  REQUIRED.  The values for the attribute "region" are
     used to determine what policy area may require consideration
     before a trace can be approved.  The PolicyRegion may include
     multiple selections from the attribute list in order to fit all
     possible policy considerations when crossing regions, consortiums,
     or networks.

  region

     One or many.  REQUIRED.  ENUM.  The attribute region is used to
     identify the expected sharing range of the incident information.
     The region may be within a region or defined by existing
     relationships such as those of a consortium or a client to a
     service provider.

     1.  ClientToSP.  A client initiated the request to their service
         provider (SP).  A client may be an individual, enterprise, or
         other type of entity (government, commercial, education,
         etc.).  An SP may be a network, telecommunications,
         infrastructure, or other type of SP where a client-to-vendor
         relationship has been established.  The client-to-vendor
         relationship will typically have established contracts or
         agreements to define expectations and trust relationships.

     2.  SPToClient.  An SP initiated a RID request or report to a
         client.  A client may be an individual, enterprise, or other
         type of entity (government, commercial, education, etc.).  An
         SP may be a network, telecommunications, infrastructure, or
         other type of SP where a client-to-vendor relationship has
         been established.  The client-to-vendor relationship will
         typically have established contracts or agreements to define
         expectations and trust relationships.






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     3.  IntraConsortium.  Incident information that should have no
         restrictions within the boundaries of a consortium with the
         agreed-upon use and abuse guidelines.  A consortium is a well-
         defined group with established members and trust relationships
         specific to sharing within that group.  A consortium would
         typically define the types of data that can be shared in
         advance, define the expectations on protecting that data, as
         well as have established contractual agreements.  Examples of
         consortiums may include industry-focused sharing communities
         (financial, government, research and education, etc.) or cross
         industry sharing communities (for instance, organizations
         within local proximity that form a sharing group).

     4.  PeerToPeer.  Incident information that should have no
         restrictions between two peers but may require further
         evaluation before continuance beyond that point with the
         agreed-upon use and abuse guidelines.  PeerToPeer
         communications may involve any two individuals or entities
         that decide to share information directly with each other.

     5.  BetweenConsortiums.  Incident information that should have no
         restrictions between consortiums that have established agreed-
         upon use and abuse guidelines.  BetweenConsortiums is used
         when two consortiums (as defined in IntraConsortium above)
         share data.  The types of data that can be shared
         BetweenConsortiums should be identified in their agreements
         and contracts along with expectations on how that data should
         be handled and protected.

     6.  ext-value.  An escape value used to extend this attribute.
         See IODEF [RFC5070], Section 5.1.

  TrafficType

     One or many.  REQUIRED.  The values for the attribute "type" are
     meant to assist in determining if a trace is appropriate for the
     SP receiving the request to continue the trace.  Multiple values
     may be selected for this element; however, where possible, it
     should be restricted to one value that most accurately describes
     the traffic type.

  type

     One or many.  REQUIRED.  ENUM.  The attribute type is used to
     identify the type of information included in the RID message or
     the type of incident.





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     1.  Attack.  This option SHOULD only be selected if the traffic is
         related to an information security incident or attack.  The
         type of attack MUST also be listed in more detail in the IODEF
         Method and Impact classes for further clarification to assist
         in determining if the trace can be continued ([RFC5070],
         Sections 3.9 and 3.10.1).

     2.  Network.  This option MUST only be selected when the trace is
         related to network traffic or routing issues.

     3.  Content.  This category MUST be used only in the case in which
         the request is related to the content and regional
         restrictions on accessing that type of content exist.  This is
         not malicious traffic but may be used for determining what
         sources or destinations accessed certain materials available
         on the Internet, including, but not limited to, news,
         technology, or inappropriate content.

     4.  DataWithHandlingRequirements.  This option is used when data
         shared may have additional restrictions for handling,
         protection, and processing based on the type of data and where
         it resides.  Regulatory or legal restrictions may be imposed
         on specific types of data that could vary based on the
         location, region or nation, of the data or where it
         originated.  The IODEF document, as well as any extensions,
         included with the RID message should indicate the specific
         restrictions to be considered.  The use of this enumeration
         flag is not legally binding.

     5.  AudienceRestriction.  This option is used to indicate that the
         message contains data that should be viewed by a restricted
         audience.  This setting should not be used for normal
         incidents or reporting as it could slow response times.  The
         content may be a business-relevant notification or request.
         This option MAY be used by a business partner to report or
         request assistance if an incident has affected a supply chain.
         This option may also be used if the content is relevant to
         regulatory obligations, legal (eDiscovery), or other use cases
         that require management attention.

     6.  Other.  If this option is selected, a description of the
         traffic type MUST be provided so that policy decisions can be
         made to continue or stop the investigation.  The information
         should be provided in the IODEF message in the Expectation
         class or in the History class using a HistoryItem log.  This
         may also be used for incident types other than information-
         security-related incidents.




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     7.  ext-value.  An escape value used to extend this attribute.
         See IODEF [RFC5070], Section 5.1.

     ReportSchema

        Zero or One.  The ReportSchema class is used by the message
        types that require the full IODEF schema to be included in the
        RID envelope.  Alternate schemas may be included if approved by
        the Designated Reviewer and registered by IANA for use with
        RID.

  The RIDPolicy class has five attributes:

     restriction

        OPTIONAL.  ENUM.  This attribute indicates the disclosure
        guidelines to which the sender expects the recipient to adhere.
        This guideline provides no real security since it is the choice
        of the recipient of the document to honor it.  This attribute
        follows the same guidelines as "restriction" used in IODEF.

     MsgType

        One.  REQUIRED.  ENUM.  The type of RID message sent.  The five
        types of messages are described in Section 4.2 and can be noted
        as one of the six selections below, where a Request is set to
        either 'InvestigationRequest' or 'TraceRequest'.

        1.  TraceRequest.  This Request message may be used to initiate
            a TraceRequest or to continue a TraceRequest to an upstream
            network closer to the source address of the origin of the
            security incident.

        2.  Acknowledgement.  This message is sent to the initiating
            RID system from each of the upstream RID systems to provide
            information on the request status in the current network.

        3.  Result.  This message indicates that the source of the
            attack was located, and the message is sent to the
            initiating RID system through the RID systems in the path
            of the trace.










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        4.  InvestigationRequest.  This Request message type is used
            when the source of the traffic is believed to be valid.
            The purpose of the InvestigationRequest is to leverage the
            existing peer or consortium relationships in order to
            notify the SP closest to the source of the valid traffic
            that some event occurred, which may be a security-related
            incident.

        5.  Report.  This message is used to report a security incident
            for which no action is requested in the IODEF Expectation
            class.  This may be used for the purpose of correlating
            attack information by CSIRTs, gathering statistics and
            trending information, etc.

        6.  Query.  This message is used to request information from a
            trusted RID system about an incident or incident type.

     Additionally, there is an extension attribute to add new
     enumerated values:

        ext-value.  An escape value used to extend this attribute.  See
        IODEF [RFC5070], Section 5.1.

     MsgDestination

        One.  REQUIRED.  ENUM.  The destination required at this level
        may either be the RID messaging system intended to receive the
        request, or, in the case of a Request with MsgType set to
        'InvestigationRequest', the source of the incident.  In the
        case of an InvestigationRequest, the RID system that can help
        stop or mitigate the traffic may not be known, and the message
        may have to traverse RID messaging systems by following the
        routing path to the RID system closest to the source of the
        attack traffic.  The Node element lists either the RID system
        or the IP address of the source, and the meaning of the value
        in the Node element is determined by the MsgDestination
        element.

        1.  RIDSystem.  The IP address of the next upstream system
            accepting RID communications is REQUIRED and is listed in
            the Node element of the RIDPolicy class.  If NodeName
            element of the Node class is used, it contains a DNS domain
            name.  The originating RID system is required to check that
            this domain name resolves to the IP address to which the
            RID message is sent.  This check may be performed in
            advance of sending the message and the result saved for
            future use with additional RID messages.




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        2.  SourceOfIncident.  The Address element of the Node element
            contains the IP address of the incident source, and the
            NodeName element of the Node class is not used.  The IP
            address is REQUIRED when this option is selected.  The IP
            address is used to determine the path of systems accepting
            RID communications that will be used to find the closest
            RID system to the source of an attack in which the IP
            address used by the source is believed to be valid and a
            Request message with MsgDestination set to
            'InvestigationRequest' is used.  This is not to be confused
            with the IncidentSource class, as the defined value here is
            from an initial Request ('InvestigationRequest' or
            'TraceRequest'), not the source used in a Result message.

        3.  ext-value.  An escape value used to extend this attribute.
            All extensions shall specify the contents and meaning of
            the Node element of RIDPolicy.  See IODEF [RFC5070],
            Section 5.1, on extensibility.  If the NodeName element of
            the Node class is used by an extension, NodeName may
            contain an Internationalized Domain Name (IDN); see
            Section 11 for applicable requirements.  All extensions
            SHOULD use an IP address in the Address element of the Node
            class as the primary means of Node identification.

     MsgType-ext

        OPTIONAL.  STRING.  A means by which to extend the MsgType
        attribute.  See IODEF [RFC5070], Section 5.1.

     MsgDestination-ext

        OPTIONAL.  STRING.  A means by which to extend the
        MsgDestination attribute.  See IODEF [RFC5070], Section 5.1

5.1.1.  ReportSchema

  The ReportSchema class is an aggregate class in the RIDPolicy class.
  The IODEF schema is the approved schema for inclusion in RID messages
  via the ReportSchema class.












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         +-------------------------+
         |      ReportSchema       |
         +-------------------------+
         |                         |
         |  ENUM Version           |
         |  STRING ext-Version     |<>---{1}-------[ XMLDocument   ]
         |  ENUM XMLSchemaID       |
         |  STRING ext-XMLSchemaID |<>---{0..1}----[ URL           ]
         |                         |
         |                         |<>---{0..*}----[ Signature     ]
         |                         |
         +-------------------------+

                    Figure 5: The ReportSchema Class

  The elements that constitute the ReportSchema class are as follows:

     XMLDocument

        One.  The XMLDocument is a complete XML document defined by the
        iodef:ExtensionType class.  This class follows the guidelines
        in [RFC5070], Section 5, where the data type is set to 'xml'
        and meaning is set to 'xml' to include an XML document.

     URL

        Zero or One.  URL.  A reference to the XML schema of the XML
        document included.  The URL data type is defined in [RFC5070],
        Section 2.15, as "xs:anyURI" in the schema.  The schemaLocation
        for IODEF is already included in the RID schema, so this is not
        necessary to include a URL for IODEF documents.  The list of
        registered schemas for inclusion will be maintained by IANA.

     Signature

        Zero to many.  The Signature uses the iodef:ExtensionType class
        to enable this element to contain a detached or enveloped
        signature.  This class follows the guidelines in [RFC5070]
        Section 5 where the data type is set to 'xml' and meaning is
        set to 'xml' to include an XML document.  This element is used
        to encapsulate the detached signature based on the iodef:
        RecordItem class within the IODEF document to verify the
        originator of the message or to include the enveloped
        signature.  If other schemas are used instead of IODEF, they
        MUST provide guidance on what class to use if a detached
        signature is provided for this purpose.





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     The ReportSchema class has four attributes:

     Version

        OPTIONAL.  One.  The Version attribute is the version number of
        the specified XML schema.  That schema must be an approved
        version of IODEF or a schema registered with IANA for use with
        RID.  The IANA registry for managing schemas other than IODEF
        is specified in Section 12.

           ext-value.  An escape value used to extend this attribute.
           See IODEF [RFC5070], Section 5.1.

     ext-Version

        OPTIONAL.  One.  The ext-Version attribute is the version
        number of the included XML schema.  This attribute is used if a
        schema other than IODEF or an IANA-registered schema that has
        been added to the enumerated list for Version is included.

     XMLSchemaID

        OPTIONAL.  One.  The XMLSchemaID attribute is the identifier,
        the defined namespace [XMLNames], of the XML schema of the XML
        document included.  The XMLSchemaID and Version specify the
        format of the XMLDocument element.  The only permitted values,
        include the namespace for IODEF [RFC5070],
        "urn:ietf:params:xml:ns:iodef-1.0", any future IETF-approved
        versions of IODEF, and any namespace included in the IANA-
        managed list of registered schemas for use with RID.  The IANA
        registry for managing schemas other than IODEF is specified in
        Section 12.

           ext-value.  An escape value used to extend this attribute.
           See IODEF [RFC5070], Section 5.1.

     ext-XMLSchemaID

        OPTIONAL.  One.  The ext-XMLSchemaID attribute is the
        identifier (defined namespace) of the XML schema of the XML
        document included.  The ext-XMLSchemaID and ext-Version specify
        the format of the XMLDocument element and are used if the
        included schema is not IODEF version 1.0 or an IANA-registered
        schema that has been added to the enumerated list for
        XMLSchemaID.






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5.2.  RequestStatus

  The RequestStatus class is an aggregate class in the RID class.

                      +--------------------------------+
                      | RequestStatus                  |
                      +--------------------------------+
                      |                                |
                      | ENUM restriction               |
                      | ENUM AuthorizationStatus       |
                      | ENUM Justification             |
                      | STRING ext-AuthorizationStatus |
                      | STRING ext-Justification       |
                      |                                |
                      +--------------------------------+

                    Figure 6: The RequestStatus Class

  The RequestStatus class has five attributes:

     restriction

        OPTIONAL.  ENUM.  This attribute indicates the disclosure
        guidelines to which the sender expects the recipient to adhere.
        This guideline provides no real security since it is the choice
        of the recipient of the document to honor it.  This attribute
        follows the same guidelines as "restriction" used in IODEF.

     AuthorizationStatus

        One.  REQUIRED.  ENUM.  The listed values are used to provide a
        response to the requesting CSIRT of the status of a Request,
        Report, or Query.

        1.  Approved.  The trace was approved and will begin in the
            current SP.

        2.  Denied.  The trace was denied in the current SP.  The next
            closest SP can use this message to filter traffic from the
            upstream SP using the example packet to help mitigate the
            effects of the attack as close to the source as possible.
            The Acknowledgement message must be passed back to the
            originator and a Result message must be used from the
            closest SP to the source in order to indicate actions taken
            in the IODEF History class.






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        3.  Pending.  Awaiting approval; a timeout period has been
            reached, which resulted in this Pending status and
            Acknowledgement message being generated.

        4.  ext-value.  An escape value used to extend this attribute.
            See IODEF [RFC5070], Section 5.1.

        Justification

           OPTIONAL.  ENUM.  Provides a reason for a Denied or Pending
           message.

           1.  SystemResource.  A resource issue exists on the systems
               that would be involved in the request.

           2.  Authentication.  The enveloped digital signature
               [RFC3275] failed to validate.

           3.  AuthenticationOrigin.  The detached digital signature
               for the original requestor on the RecordItem entry
               failed to validate.

           4.  Encryption.  The recipient was unable to decrypt the
               request, report, or query.

           5.  UnrecognizedFormat.  The format of the provided document
               was unrecognized.

           6.  CannotProcess.  The document could not be processed.
               Reasons may include legal or policy decisions.
               Resolution may require communication outside of this
               protocol to resolve legal or policy issues.  No further
               messages SHOULD be sent until resolved.

           7.  Other.  There were other reasons this request could not
               be processed.

           8.  ext-value.  An escape value used to extend this
               attribute.  See IODEF [RFC5070], Section 5.1.

        AuthorizationStatus-ext

           OPTIONAL.  STRING.  A means by which to extend the
           AuthorizationStatus attribute.  See IODEF [RFC5070], Section
           5.1.






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        Justification-ext

           OPTIONAL.  STRING.  A means by which to extend the
           Justification attribute.  See IODEF [RFC5070], Section 5.1.

5.3.  IncidentSource

  The IncidentSource class is an aggregate class in the RID class.

         +-------------------+
         | IncidentSource    |
         +-------------------+
         |                   |
         | ENUM restriction  |
         |                   |<>-------------[ SourceFound    ]
         |                   |
         |                   |<>---{0..*}----[ Node           ]
         |                   |
         +-------------------+

                   Figure 7: The IncidentSource Class

  The elements that constitute the IncidentSource class follow:

     SourceFound

        One.  BOOLEAN.  The Source class indicates if a source was
        identified.  If the source was identified, it is listed in the
        Node element of this class.

        True.  Source of incident was identified.

        False.  Source of incident was not identified.

     Node

        Zero or many.  The Node class is used to identify a system
        identified as part of an incident.  If this element is used,
        the Address element of the Node element MUST contain the IP
        address of the system.  If the NodeName element of the Node
        class is used, it contains a DNS domain name that has been
        checked to ensure that it resolved to that IP address when the
        check was performed.  See Section 11 of this document for
        internationalization considerations for NodeName.  The base
        definition of this class from the IODEF ([RFC5070], Section
        3.16) can be expanded to include other identifiers.





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     The IncidentSource class has one attribute:

     restriction

        OPTIONAL.  ENUM.  This attribute indicates the disclosure
        guidelines to which the sender expects the recipient to
        adhere.This guideline provides no real security since it is the
        choice of the recipient of the document to honor it.  This
        attribute follows the same guidelines as "restriction" used in
        IODEF.

5.4.  RID Name Spaces

  The RID schema declares a namespace of
  "urn:ietf:params:xml:ns:iodef-rid-2.0" and registers it per
  [RFC3688].  Each IODEF-RID document MUST use the "iodef-rid-2.0"
  namespace in the top-level element RID-Document.  It can be
  referenced as follows:

  <RID-Document version="2.0" lang="en-US"
     xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
     xmlns:xsi="http://www.w3c.org/2001/XMLSchema-instance"
     xsi:schemaLocation="urn:ietf:params:xml:ns:iodef-rid-2.0.xsd">

5.5.  Encoding

  RID documents MUST begin with an XML declaration and MUST specify the
  XML version used; also, the use of UTF-8 encoding is REQUIRED
  ([RFC3470], Section 4.4).  RID conforms to all XML data encoding
  conventions and constraints.

  The XML declaration with no character encoding will read as follows:

     <?xml version="1.0" encoding="UTF-8"?>

  The following characters have special meaning in XML and MUST be
  escaped with their entity reference equivalent: "&", "<", ">", "\""
  (double quotation mark), and "'" (apostrophe).  These entity
  references are "&amp;", "&lt;", "&gt;", "&quot;", and "&apos;",
  respectively.

5.6.  Including IODEF or Other XML Documents

  In order to support the changing activity of CSIRTS, the RID schema
  can include an IODEF or other data model.  The IODEF is also
  extensible, enabling the schemas to evolve along with the needs of
  CSIRTs.  This section discusses how to include the IODEF XML document
  or other XML documents to leverage the security and trust



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  relationships established through the use of RID.  These techniques
  are designed so that adding new data will not require a change to the
  RID schema.  This approach also supports the exchange of private XML
  documents relevant only to a closed consortium.  XML documents can be
  included through the ReportSchema class in the RIDPolicy class.  The
  XMLDocument attribute is set to 'xml' to allow for the inclusion of
  full IODEF or other XML documents.  The following guidelines MUST be
  followed:

  1.  The included schema MUST define a separate namespace, such as the
      declared namespace for IODEF of
      "urn:ietf:params:xml:ns:iodef-1.0".

  2.  When a parser encounters an included XML document it does not
      understand, the included document MUST be ignored (and not
      processed), but the remainder of the document MUST be processed.
      Parsers will be able to identify the XML documents for which they
      have no processing logic through the namespace declaration.
      Parsers that encounter an unrecognized element in a namespace
      that they do support SHOULD reject the document as a syntax
      error.

  3.  Implementations SHOULD NOT download schemas at runtime due to the
      security implications, and included documents MUST NOT be
      required to provide a resolvable location of their schema.

  The examples included in Section 7 demonstrate how an IODEF document
  is included.  The included schema of IODEF is represented in
  ReportSchema as follows:

     Version: "1.0"

     XMLSchemaID: "urn:ietf:params:xml:ns:iodef-1.0"

     URL: "http://www.iana.org/assignments/xml-registry/schema/
     iodef-1.0.xsd"

  The URL is optionally included for IODEF since it is already in the
  RID schema, and the schemaLocation is defined.

5.6.1.  Including XML Documents in RID

  XML schemas may be registered for inclusion in a RID message.  This
  may include schemas other than IODEF or updated versions of IODEF.
  The registered IANA information for additional schemas MUST include
  the specification name, version, specification Uniform Resource
  Identifier (URI), and namespace.  The following provides an example
  of the necessary information for additional schemas beyond IODEF.



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  Example Name (XXXX)

     Schema Name:   XXXX_1.1
     Version:       1.1
     Namespace:     <registered namespace>
     Specification URI:  http://www.example.com/XXXX

  The version attribute of the ReportSchema class is populated with the
  approved versions of IODEF or any additional schemas registered by
  IANA; see Section 12.

  The XMLSchemaID of the ReportSchema class is populated with the
  namespace of the included schema.  The attribute enumeration values
  include the namespace for IODEF and any schema registered by IANA;
  see Section 12.

  The URL element of the ReportSchema class is populated with the
  Specification URI value of the included schema.

6.  RID Messages

  The IODEF model is followed as specified in [RFC5070] for each of the
  RID message types.  The RID schema is used in combination with IODEF
  documents to facilitate RID communications.  Each message type varies
  slightly in format and purpose; hence, the requirements vary and are
  specified for each.  All classes, elements, attributes, etc., that
  are defined in the IODEF-Document are valid in the context of a RID
  message; however, some listed as optional in IODEF are mandatory for
  RID as listed for each message type.  The IODEF model MUST be fully
  implemented for RID messages that include IODEF payloads to ensure
  proper parsing of those messages.

  Note: The implementation of RID may automate the ability to fill in
  the content required for each message type from packet input,
  incident data, situational awareness information, or default values
  such as those used in the EventData class.

6.1.  Request

  Description: This message type is used to request assistance in a
  computer security investigation.  The investigation request may be
  directed to another party that can assist with forensics and continue
  the investigation (the incident may have originated on the SP network
  to which the Request was sent), or it may be directed to an SP to
  trace the traffic from an unknown source.  The Request message with
  MsgType set to 'InvestigationRequest' may leverage the existing
  bilateral peer relationships in order to notify the SP closest to the
  source of the valid traffic that some event occurred, which may be a



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  security-related incident.  A Request message with the MsgType set to
  'TraceRequest' may be sent to an upstream peer to trace back through
  the network to locate the source of malicious traffic.  The following
  information is REQUIRED for Request messages and is provided through
  the following data structures:

  RID Information:

     RIDPolicy

        RID message type, IncidentID, and destination policy
        information

  IODEF Information:

     Timestamps (DetectTime, StartTime, EndTime, ReportTime).

     Incident Identifier (Incident class, IncidentID).

     Confidence rating of security incident (Impact and Confidence
     class).

     System class is used to list both the Source and Destination.

     Expectation class should be used to request any specific actions
     to be taken close to the source.

     Path information of nested RID systems, beginning with the request
     originator used in the trace using IODEF EventData with category
     set to 'infrastructure'.

     Event, Record, and RecordItem classes to include example packets
     and other information related to the incident.  Note: Event
     information included here requires a second instance of EventData
     in addition to that used to convey SP path contact information.

  Standards for encryption and digital signatures [RFC3275] [XMLsig]
  [XMLencrypt]:

     Digital signature from initiating CSIRT or provider system sending
     the RID message, passed to all systems receiving the Request using
     a detached XML digital signature on a RecordItem entry, placed in
     an instance of the Signature element.

     Digital signature of sending CSIRT or SP for authenticity of the
     RID message, from the CSIRT or provider creating this message
     using an enveloped XML digital signature on the IODEF document,
     placed in an instance of the Signature element.



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     XML encryption as required by policy, agreements, and data
     markers.

  Security requirements include the ability to encrypt [XMLencrypt] the
  contents of the Request message using the public key of the
  destination RID system.  The incident number increases whether the
  Request message has the MsgDestination set to 'InvestigationRequest'
  or 'TraceRequest' in order to ensure uniqueness within the system.
  The relaying peers also append their Autonomous System (AS) or RID
  system information using the path information as the Request message
  was relayed through SPs.  This enables the response (Result message)
  to utilize the same path and trust relationships for the return
  message, indicating any actions taken.  The request is recorded in
  the state tables of both the initiating and destination SP RID
  systems.  The destination SP is responsible for any actions taken as
  a result of the request in adherence to any service level agreements
  or policies.  The SP MUST confirm that the traffic actually
  originated from the suspected system before taking any action and
  confirm the reason for the request.  The request may be sent directly
  to a known RID system or routed by the source address of the attack
  using the MsgDestination of RIDPolicy set to 'SourceOfIncident'.
  Note: Any intermediate parties in a TraceRequest MUST be able to view
  RIDPolicy information of responding message types in order to
  properly direct RID messages.

  A DDoS attack can have many sources, resulting in multiple traces to
  locate the sources of the attack.  It may be valid to continue
  multiple traces for a single attack.  The path information enables
  the administrators to determine if the exact trace already passed
  through a single network.  The Incident Identifier must also be used
  to identify multiple Requests from a single incident.  If a single
  Request results in divergent paths of Requests, a separate instance
  number MUST be used under the same IncidentID.  The IncidentID
  instance number of IODEF can be used to correlate related incident
  data that is part of a larger incident.

6.2.  Acknowledgement

  Description: The Acknowledgement is also used to provide a status to
  any message type and to provide a Justification if the message could
  not be processed for any reason.  This message is sent to the
  initiating RID system from the next upstream provider's application
  or system designated for accepting RID communications to provide
  information on the request status in the current SP.

  The following information is REQUIRED for Acknowledgement messages
  and is provided through the following data structures:




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  RID Information:

     RIDPolicy

        RID message type, IncidentID, and destination policy
        information

     RequestStatus class:

        Status of Request

  Standards for encryption and digital signatures [RFC3275], [XMLsig],
  [XMLencrypt]:

     Digital signature of responding CSIRT or provider for authenticity
     of Trace Status Message, from the CSIRT or provider creating this
     message using an enveloped XML digital signature.

     XML encryption as required by policy, agreements, and data
     markers.

  A message is sent back to the initiating CSIRT or provider's system;
  it accepts RID communications of the trace as status notification.
  This message verifies that the next RID system in the path has
  received the message from the previous system in the path.  This
  message also verifies that the trace is now continuing, has stopped,
  or is pending in the next upstream CSIRT or provider's RID system.
  The Pending status is automatically generated after a 2-minute
  timeout without system-predefined or administrator action to approve
  or disapprove the trace continuance.  If a Request is denied, the
  originator and sending peer (if they are not the same) MUST both
  receive the message.  This provides the sending peer with the option
  to take action to stop or mitigate the traffic as close to the source
  as possible.

6.3.  Result

  Description: This message indicates that the trace or investigation
  has been completed and provides the result.  The Result message
  includes information on whether or not a source was found, and the
  source information is provided through the IncidentSource class.  The
  Result information MUST go back to the originating RID system that
  began the investigation or trace.  A provider may use any number of
  incident-handling data sources to ascertain the true source of an
  attack.  All of the possible information sources may or may not be
  readily tied into the RID communications system.





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  The following information is REQUIRED for Result messages and will be
  provided through the following data structures:

     RID Information:

        RIDPolicy

           RID message type, IncidentID, and destination policy
           information

        Incident Source

           The IncidentSource class of the RID schema is used to note
           if a source was identified and provide the source
           address(es) or other Node information.

     IODEF Information:

        Timestamps (DetectTime, StartTime, EndTime, ReportTime).

        Incident Identifier (Incident class, IncidentID).

           Trace number is used for multiple traces of a single
           incident; it MUST be included if the response is specific to
           an instance of an incident.

        Confidence rating of security incident (Impact and Confidence
        class).

        System class is used to list both the Source and Destination
        Information used in the attack and must note if the traffic is
        spoofed, thus requiring in RID an upstream Request set to
        'TraceRequest'.

        History class "atype" attribute is used to note any actions
        taken.

        History class also notes any other background information
        including notes about the Confidence level or rating of the
        result information.

        Path information of nested RID systems, beginning with the
        request originator used in the trace using IODEF EventData with
        category set to 'infrastructure'.  The last SP listed is the SP
        that located the source of the traffic (the provider sending
        the Result message).





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        Event, Record, and RecordItem classes to include example
        packets and other information related to the incident
        (optional).  Note: Event information included here requires a
        second instance of EventData in addition to that used to convey
        SP path contact information.

     Standards for encryption and digital signatures [RFC3275],
     [XMLsig], [XMLencrypt]:

        Digital signature of source CSIRT or provider for authenticity
        of Result message, from the CSIRT or provider creating this
        message using an enveloped XML digital signature.

        XML encryption as required by policy, agreements, and data
        markers.

  A message is sent back to the initiating CSIRT or provider's RID
  system to notify the CSIRT that the source has been located.  The
  actual source information may or may not be included, depending on
  the policy of the network in which the client or host is attached.
  Any action taken by the SP to act upon the discovery of the source of
  a trace should be included.  The SP may be able to automate the
  adjustment of filters at their border router to block outbound access
  for the machine(s) discovered as a part of the attack.  The filters
  may be comprehensive and block all Internet access until the host has
  taken the appropriate action to resolve any security issues.  The SP
  may be limited in their options for filtering due to agreements or
  other restrictions resulting in less comprehensive filters, such as
  rate-limiting the ingress traffic as close to the source as possible.

  Security and privacy requirements discussed in Section 9 MUST be
  taken into account.

  Note: The History class has been expanded in IODEF to accommodate all
  of the possible actions taken as a result of a RID Request using the
  "iodef:atype", or action type, attribute.  The History class should
  be used to note all actions taken close to the source of a trace or
  incident using the most appropriate option for the type of action
  along with a description.  The "atype" attribute in the Expectation
  class can also be used to request an appropriate action when a
  Request is made.

6.4.  Report

  Description: This message or document is sent to a RID system to
  provide a report of a security incident.  This message does not
  require any actions to be taken, except to file the report on the
  receiving RID system or associated database.



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  The following information is REQUIRED for Report messages and will be
  provided through the following data structures:

     RID Information:

        RIDPolicy RID message type, IncidentID, and destination policy
        information

     The following data is RECOMMENDED if available and can be provided
     through the following data structures:

     IODEF Information:

        Timestamps (DetectTime, StartTime, EndTime, ReportTime).

        Incident Identifier (Incident class, IncidentID).

           Trace number is used for multiple traces of a single
           incident; it MUST be included if the Report is specific to
           an instance of an incident.

        Confidence rating of security incident (Impact and Confidence
        class).

        System class is used to list both the Source and Destination
        Information used in the attack.

        Event, Record, and RecordItem classes are used to include
        example packets and other information related to the incident
        (optional).

     Standards for encryption and digital signatures [RFC3275],
     [XMLsig], [XMLencrypt]:

        Digital signature from initiating RID system, passed to all
        systems receiving the report using an enveloped XML digital
        signature, placed in an instance of the Signature element.

        XML encryption as required by policy, agreements, and data
        markers.

  Security requirements include the ability to encrypt [XMLencrypt] the
  contents of the Report message using the public key of the
  destination RID system.  Senders of a Report message should note that
  the information may be used to correlate security incident
  information for the purpose of trending, pattern detection, etc., and
  may be shared with other parties unless otherwise agreed upon with
  the receiving RID system.  Therefore, sending parties of a Report



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  message may obfuscate or remove destination addresses or other
  sensitive information before sending a Report message.  A Report
  message may be sent either to file an incident report or to respond
  to a Query, and data sensitivity must be considered in both cases.
  The SP path information is not necessary for this message, as it will
  be communicated directly between two trusted RID systems.

6.5.  Query

  Description: The Query message is used to request incident
  information from a trusted RID system.  The request can include the
  incident number, if known, or detailed information about the
  incident.  If the incident number is known, the Report message
  containing the incident information can easily be returned to the
  trusted requestor using automated methods.  If an example packet or
  other unique information is included in the Query, the return report
  may be automated; otherwise, analyst intervention may be required.

  The following information is REQUIRED for a Query message and is
  provided through the following data structures:

     RID Information:

        RIDPolicy

           RID message type, IncidentID, and destination policy
           information

     IODEF Information (optional):

        Timestamps (DetectTime, StartTime, EndTime, ReportTime).

        Incident Identifier (Incident class, IncidentID).

           Trace number is used for multiple traces of a single
           incident; it MUST be included if the Query is an instance of
           an incident.

        Confidence rating of security incident (Impact and Confidence
        class).

        System class is used to list both the Source and Destination
        Information used in the attack.

        Event, Record, and RecordItem classes are used to include
        example packets and other information related to the incident
        (optional).




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     Standards for encryption and digital signatures [RFC3275],
     [XMLsig], [XMLencrypt]:

        Digital signature from the CSIRT or SP initiating the RID
        message, passed to all systems receiving the Query using an
        enveloped XML digital signature, placed in an instance of the
        Signature element.

        XML encryption as required by policy, agreements, and data
        markers.

  The proper response to the Query message is a Report message.
  Multiple incidents may be returned for a single query if an incident
  type is requested.  In this case, the receiving system sends an IODEF
  document containing multiple incidents or all instances of an
  incident.  The system sending the reply may preset a limit to the
  number of documents returned in one report.  The recommended limit is
  5, to prevent the documents from becoming too large.  Other transfer
  methods may be better suited than RID for large transfers of data.
  The Confidence rating may be used in the Query message to select only
  incidents with an equal or higher Confidence rating than what is
  specified.  This may be used for cases when information is gathered
  on a type of incident but not on specifics about a single incident.
  Source and Destination Information may not be needed if the Query is
  intended to gather data about a specific type of incident.

7.  RID Communication Exchanges

  The following section outlines the communication flows for RID and
  also provides examples of messages.

  The possible set of message exchanges include:

  o  Request: Asynchronous Request for assistance and/or action to be
     taken, MAY involve multiple systems and iterative Requests

        MsgType set to 'InvestigationRequest' or 'TraceRequest'

        Possible responses:

        +  Acknowledgement (OPTIONAL for InvestigationRequest)

        +  Result (REQUIRED unless Acknowledgement was set to 'no')

        +  Report (OPTIONAL; zero or more; Report can be sent
           unsolicited)





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  o  Query: Synchronous request for information

        MsgType set to 'Query'

        Possible responses:

        +  Acknowledgement (OPTIONAL if yes; REQUIRED if no Report will
           be sent)

        +  Report (REQUIRED unless Acknowledgement was set to 'no')

  o  Report: Asynchronous information report; may be pushed to systems
     or may be a response to a Query

        MsgType set to 'Report'

        Possible responses:

        +  Acknowledgement (OPTIONAL)

  Processing considerations for the IODEF document and any IODEF
  included elements or attributes MUST follow the guidelines specified
  in [RFC5070], Section 4.  [RFC3023] and [RFC3470] specify
  requirements and best practices for the use of XML in IETF
  application protocols.  RID and IODEF documents MUST be well-formed
  (see [RFC3470], Section 4.1) and MUST be validated against the
  appropriate schema.  Internal or external DTD subsets are prohibited
  in RID; see [RFC3023], Section 3.

  Comments can be ignored by conform ant processors for RID or IODEF
  documents (see [RFC3470], Section 4.6) and are included below for
  informational purposes only.  The first example demonstrates the use
  of a detached digital signature.  Subsequent examples do not include
  the detached signature required for some message types.  The
  signature is applied after the message is created as demonstrated in
  the first example.

  Note: For each example listed below, [RFC5735] addresses were used.
  Assume that each IP address listed is actually a separate network
  range held by different SPs.  Addresses were used from /27 network
  ranges.

7.1.  Upstream Trace Communication Flow

  The diagram below outlines the RID Request communication flow for a
  TraceRequest between RID systems on different networks tracing an
  attack.  The Request message with MsgDestination set to




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  'TraceRequest' is represented in the diagram by "TraceRequest".
  SP-1, SP-2, and SP-3 represent service providers that are involved in
  the example trace communication flow.

   Attack Dest      SP-1            SP-2        SP-3        Attack Src

   1. Attack    |  Attack
      reported  |  detected

   2.              Initiate trace

   3.              Locate origin
                   through
                   upstream SP

   4.              o---TraceRequest----->

   5.                              Trace
                                   Initiated

   6.              <---Acknowledgement--o

   7.                              Locate origin
                                   through
                                   upstream SP

   8.                              o---TraceRequest--->

   9.                                             Trace Initiated

   10.             <----------Acknowledgement----o
                                    <-Acknowledgement-o

   11.                                            Locate attack
                                                  source on network   X

   12.             <------------Result----------------o

   13.             o- - - - -Acknowledgement- - - - - >


                Figure 8: TraceRequest Communication Flow

  Before a trace is initiated, the RID system should verify that an
  instance of the trace or a similar request is not active.  The traces
  may be resource intensive; therefore, providers need to be able to
  detect potential abuse of the system or unintentional resource




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  drains.  Information such as the Source and Destination Information,
  associated packets, and the incident may be desirable to maintain for
  a period of time determined by administrators.

  The communication flow demonstrates that an Acknowledgement message
  is sent to both the downstream peer and the original requestor.  If a
  Request in a traceback is denied, the downstream peer has the option
  to take an action and respond with a Result message.  The originator
  of the request may follow up with the downstream peer of the SP
  involved using a Request with the MsgType set to
  'InvestigationRequest' to ensure that an action is taken if no
  response is received.  Nothing precludes the originator of the
  request from initiating a new Request with the MsgType set to
  'TraceRequest' thereby bypassing the SP that denied the request, if a
  trace is needed beyond that point.  Another option may be for the
  initiator to send an 'InvestigationRequest' to an SP upstream of the
  SP that denied the request.  This action assumes enough information
  was gathered to discern the true source of the attack traffic from
  the incident-handling information.

  The proper response to a TraceRequest is an Acknowledgement message.
  The Acknowledgement message lets the requestor know if the trace will
  continue through the next upstream network.  If there is a problem
  with the request, such as a failure to validate the digital signature
  or decrypt the request, an Acknowledgement message MUST be sent to
  the requestor and the downstream peer (if they are not one and the
  same) providing the reason why the message could not be processed.
  Assuming that the trace continued, additional TraceRequests with the
  response of an Acknowledgement message would occur, thereby passing
  the request upstream in the path to the source of the traffic related
  to the incident.  Once a source is found, a Result message is sent to
  the originator of the trace, as determined by the SP path information
  provided through the document instance of EventData, where contact is
  set to 'infrastructure'.  The SP path information is also used when
  sending the Acknowledgement messages to the first entry (the trace
  originator) and the last nested entry (the downstream peer).  The
  Result message is encrypted [XMLencrypt] for the originator providing
  information about the incident source and any actions taken.  If the
  originator fails to decrypt or authenticate the Result message, an
  Acknowledgement message is sent in response; otherwise, no return
  message is sent.  The final Acknowledgement to the Result message is
  depicted as optional in the diagram above.  If an Acknowledgement
  message is sent with the RequestStatus set to Denied, a downstream
  peer receiving this message may choose to take action to stop or
  mitigate the traffic at that point in the network, as close to the
  source as possible.  If the downstream peer chooses this option, it
  would send a Result message to the trace originator.




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7.1.1.  RID TraceRequest Example

  The example listed is of a Request message with MsgDestination set to
  'TraceRequest' based on the incident report example from the IODEF
  document.  The RID classes were included as appropriate for a Request
  message of this type using the RIDPolicy class.  The example given is
  that of a CSIRT reporting a DoS attack in progress to the upstream
  SP.  The request asks the next SP to continue the trace and have the
  traffic mitigated closer to the source of the traffic.  The example
  Request message is the first step of a TraceRequest as depicted in
  the previous diagram, where 'Attack Dest' is represented by
  192.0.2.67 (and SP-1).  The 'Attack Src' is later identified in the
  Result message example as 192.0.2.37 and initially as tracing closer
  to 192.0.2.35.  SP-1 is identified in the Request as CSIRT-FOR-OUR-
  DOMAIN, and SP-2 is identified in the RID document for the Request as
  the 'RIDSystem' in 'MsgDestination' as 192.0.2.3 using the Node
  class.  SP-3 is later used in the Result message and the
  administrator is identified as '[email protected]' as they
  searched for 192.0.2.35; the administrator may be different than the
  constituency contact (an additional Request with MsgDestination set
  to 'TraceRequest' occurred between SP-2 to SP-3 that is not
  included).  SP-3 is the service provider for 192.0.2.32/27 and was
  able to take the action to rate-limit their traffic.  The SP-1, SP-2,
  and SP-3 information would be replaced with the appropriate (and
  valid) email and other contact information in real usages.  The Node
  class enables multiple methods to identify a system, such as a fully
  qualified domain name or the IP address to be provided for the SP.
  Any mapping of existing relationships from the SP Node information to
  the name, contact, digital signature verification information and
  other identifying or trust information is provided at the application
  layer to support end users of the incident management system.  A
  packet is provided in this example to enable any traces to be
  performed by SP-2 and SP-3 to perform traces to the attack source
  before taking the requested action to 'rate-limit' the traffic.  The
  subnet of 192.0.2.0 uses a 27-bit mask in the examples below.

  In the following example, use of [XMLsig] to generate digital
  signatures follows the guidance of [XMLsig] 1.0.  Version 1.1 of
  [XMLsig] supports additional digest algorithms.  Reference [RFC4051]
  for URIs intended for use with XML digital signatures, encryption,
  and canonicalization.  SHA-1 SHOULD NOT be used; see [RFC6194] for
  further details.

  Note: Due to the limit of 72 characters per line, some line breaks
  were added in the examples and schemas in this document.






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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<iodef-rid:RID lang="en-US"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:ietf:params:xml:ns:iodef-rid-2.0">
<iodef-rid:RIDPolicy MsgDestination="RIDSystem" MsgType="TraceRequest">
  <iodef-rid:PolicyRegion region="IntraConsortium"/>
    <iodef:Node>
     <iodef:Address category="ipv4-addr">192.0.2.3</iodef:Address>
    </iodef:Node>
    <iodef-rid:TrafficType type="Attack"/>
    <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
           CERT-FOR-OUR-DOMAIN#207-1
    </iodef:IncidentID>
    <!-- IODEF-Document included in RID -->
    <iodef-rid:ReportSchema Version="1.0">
     <iodef-rid:XMLDocument dtype="xml" meaning="xml">
      <IODEF-Document lang="en">
       <iodef:Incident purpose="traceback" restriction="need-to-know">
         <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
                          CERT-FOR-OUR-DOMAIN#207-1
         </iodef:IncidentID>
         <iodef:DetectTime>2004-02-02T22:49:24+00:00</iodef:DetectTime>
         <iodef:StartTime>2004-02-02T22:19:24+00:00</iodef:StartTime>
         <iodef:ReportTime>2004-02-02T23:20:24+00:00</iodef:ReportTime>
         <iodef:Description>
                          Host involved in DoS attack
         </iodef:Description>
         <iodef:Assessment>
           <iodef:Impact completion="failed" severity="low"
                         type="dos"/>
         </iodef:Assessment>
         <iodef:Contact role="creator" type="organization">
           <iodef:ContactName>Constituency-contact for 192.0.2.35
           </iodef:ContactName>
           <iodef:Email>[email protected]</iodef:Email>
         </iodef:Contact>
         <iodef:EventData>
           <iodef:Flow>
             <iodef:System category="source">
               <iodef:Node>
                 <iodef:Address category="ipv4-addr">192.0.2.35
                 </iodef:Address>
               </iodef:Node>
               <iodef:Service ip_protocol="6">
                 <iodef:Port>38765</iodef:Port>
               </iodef:Service>



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             </iodef:System>
             <iodef:System category="target">
               <iodef:Node>
                 <iodef:Address category="ipv4-addr">192.0.2.67
                 </iodef:Address>
               </iodef:Node>
               <iodef:Service ip_protocol="6">
                 <iodef:Port>80</iodef:Port>
               </iodef:Service>
             </iodef:System>
           </iodef:Flow>
           <iodef:Expectation action="rate-limit-host" severity="high">
             <iodef:Description>
                    Rate-limit traffic close to source
           </iodef:Description>
         </iodef:Expectation>
         <iodef:Record>
           <iodef:RecordData>
             <iodef:Description>
              The IPv4 packet included was used in the described attack
             </iodef:Description>
             <iodef:RecordItem dtype="ipv4-packet">450000522ad9
               0000ff06c41fc0a801020a010102976d0050103e020810d9
               4a1350021000ad6700005468616e6b20796f7520666f7220
               6361726566756c6c792072656164696e6720746869732052
               46432e0a
             </iodef:RecordItem>
            </iodef:RecordData>
           </iodef:Record>
          </iodef:EventData>
          <iodef:History>
            <iodef:HistoryItem action="rate-limit-host">
              <iodef:DateTime>
                     2001-09-14T08:19:01+00:00
              </iodef:DateTime>
              <iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
                     CSIRT-FOR-OUR-DOMAIN#207-1
              </iodef:IncidentID>
              <iodef:Description>
             Notification sent to next upstream SP closer to 192.0.2.35
              </iodef:Description>
             </iodef:HistoryItem>
            </iodef:History>
           </iodef:Incident>
          </IODEF-Document>
        </iodef-rid:XMLDocument>
      <!-- End of IODEF-Document included in RID -->
      <!-- Start of detached XML signature included in RID -->



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RFC 6545                           RID                        April 2012


      <iodef-rid:Signature dtype="xml" meaning="xml">
       <Signature xmlns="http://www.w3.org/2000/09/xmldsig#"
                  Id="dsig-123456">
       <SignedInfo>
<CanonicalizationMethod
 Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
<SignatureMethod
 Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
   <Reference URI="">
   <Transforms>
    <Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
    <Transform Algorithm="http://www.w3.org/2002/06/xmldsig-filter2">
    <XPath xmlns="http://www.w3.org/2002/06/xmldsig-filter2"
      xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"
      xmlns:dsig-trans="http://www.w3.org/2002/06/xmldsig-filter2"
      Filter="intersect">
      //dsig:Signature[@Id = 'dsig-123456']/
      ancestor::iodef-rid:ReportSchema/
      iodef-rid:XMLDocument/IODEF-Document[1]/iodef:Incident[1]/
      iodef:EventData[1]/iodef:Record[1]/iodef:RecordData[1]/
      iodef:RecordItem[1]</XPath></Transform></Transforms>
   <DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
   <DigestValue>
      NQuIhPjdZuZJnPi/hW62dwJT1dR+vqcZV8mpemCVN5g=
   </DigestValue>
  </Reference></SignedInfo>
  <SignatureValue>
lnq/ePQ4AVpxCR0ifCp9sMsW0r/AdT3C2GR/zaN1V+hZ/NApOygUjMzTCQnx+RvGPNkO/RVq
BEIDgZQUEnQZn/uSbmr0tQ6xpBfaxF1DCosLgiZy+2jFzpXrwoN/jHNgtxR/9QLW9mZ+I7V6
LEEJ73Kut+d0naTGHlyi64ab2PqsVuRXQ4pXUKbhMkhzeTIqvFLK93KGfsIMd6Cb+n2u/ABy
Lkc+gflJYUWVP4DxkQ4cyex6hM6RYTRUSr7jVD9K4d8KFP2g85i69YLtSu01W1Np0afpJ4a9
MK0E7ISMNRmC8wIklCAsSXiBRqyaEwaSy/clybI0vCTPqGOYh3/SZg==
  </SignatureValue>
  <KeyInfo>
   <KeyValue>
     <RSAKeyValue>
      <Modulus>
z8adrX9m0S8OxIxN+fui33wiz4ZYgb4xPbR9MS5pOp1A8kVpH5Ew3N6O3/dMs2a4diIxyGLV
h0r86QXWH/W6T2IC2ny+hi+jWRwXrvgTY3ZAFgePvz2OdRhVN/cUbOto4Pa4I2mVZWW+/Q0F
n7YpqPBDDxlGq/xyFPuYq/4y7Y+Ah+vHO2ZSaiQjbj8F38XrGhwlcbFVyK8AmxK3z0zWwX86
uMEqVCjW6s6j2KAWdbAjEpgZHlJY87i/DqnFgxfmdg3oru+YeiEPVRY8hyQpYbtgryveZOHT
gnCHmS/53U9jSS0cyb/ADuj1upfyNoOiMMgQr7Olhc5pTvuWAl4Fnw==</Modulus>
      <Exponent>AQAB</Exponent>
     </RSAKeyValue>
     </KeyValue>
   </KeyInfo>
  </Signature>
 </iodef-rid:Signature>



Moriarty                     Standards Track                   [Page 46]

RFC 6545                           RID                        April 2012


 <!-- End of detached XML signature included in RID -->
     </iodef-rid:ReportSchema>
  </iodef-rid:RIDPolicy>
</iodef-rid:RID>

7.1.2.  Acknowledgement Message Example

  The example Acknowledgement message is in response to the Request
  message listed above.  The SP that received the request is responding
  to approve the trace continuance in their network.

  <iodef-rid:RID lang="en"
                 xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
                 xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
    <iodef-rid:RIDPolicy MsgType="Acknowledgement"
                         MsgDestination="RIDSystem">
      <iodef-rid:PolicyRegion region="IntraConsortium"/>
      <iodef:Node>
        <iodef:Address category="ipv4-addr">192.0.2.67</iodef:Address>
      </iodef:Node>
      <iodef-rid:TrafficType type="Attack"/>
      <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
        CERT-FOR-OUR-DOMAIN#207-1
      </iodef:IncidentID>
    </iodef-rid:RIDPolicy>
    <iodef-rid:RequestStatus AuthorizationStatus="Approved"/>
  </iodef-rid:RID>

7.1.3.  Result Message Example

  The example Result message is in response to the Request listed
  above.  This message type only comes after an Acknowledgement within
  the Request flow of messages where a TraceRequest is in progress.  It
  may be a direct response to a Request with the MsgType set to
  'InvestigationRequest'.  This message provides information about the
  source of the attack and the actions taken to mitigate the traffic.
  The Result message is typically the last message in a Request flow;
  however, an Acknowledgement MAY follow if there are any issues
  receiving or processing the Result.

<iodef-rid:RID lang="en"
              xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
              xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
 <iodef-rid:RIDPolicy MsgType="Result"
                      MsgDestination="RIDSystem">
   <iodef-rid:PolicyRegion region="IntraConsortium"/>
   <iodef:Node>
     <iodef:Address category="ipv4-addr">192.0.2.67</iodef:Address>



Moriarty                     Standards Track                   [Page 47]

RFC 6545                           RID                        April 2012


   </iodef:Node>
   <iodef-rid:TrafficType type="Attack"/>
   <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
     CERT-FOR-OUR-DOMAIN#207-1
   </iodef:IncidentID>
<!-- IODEF-Document included in RID -->
   <iodef-rid:ReportSchema Version="1.0">
    <iodef-rid:XMLDocument dtype="xml" meaning="xml">
     <iodef:IODEF-Document lang="en">
     <iodef:Incident restriction="need-to-know" purpose="traceback">
       <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
         CERT-FOR-OUR-DOMAIN#207-1
       </iodef:IncidentID>
     <iodef:DetectTime>2004-02-02T22:49:24+00:00</iodef:DetectTime>
     <iodef:StartTime>2004-02-02T22:19:24+00:00</iodef:StartTime>
     <iodef:ReportTime>2004-02-02T23:20:24+00:00</iodef:ReportTime>
     <iodef:Description>Host involved in DoS attack</iodef:Description>
     <iodef:Assessment>
       <iodef:Impact severity="low" completion="failed"
                     type="dos"/>
     </iodef:Assessment>
     <iodef:Contact role="creator" type="organization">
       <iodef:ContactName>Constituency-contact for 192.0.2.35
       </iodef:ContactName>
       <iodef:Email>[email protected]</iodef:Email>
     </iodef:Contact>
     <iodef:EventData>
       <iodef:Contact role="admin" type="organization">
         <iodef:ContactName>Admin-contact for 192.0.2.35
         </iodef:ContactName>
         <iodef:Email>[email protected]</iodef:Email>
       </iodef:Contact>
       <iodef:Flow>
         <iodef:System category="intermediate">
           <iodef:Node>
             <iodef:Address category="ipv4-addr">192.0.2.35
             </iodef:Address>
           </iodef:Node>
         </iodef:System>
       </iodef:Flow>
       <iodef:EventData>
         <iodef:Contact role="admin" type="organization">
           <iodef:ContactName>Admin-contact for 192.0.2.3
           </iodef:ContactName>
           <iodef:Email>[email protected]</iodef:Email>
         </iodef:Contact>
         <iodef:Flow>
           <iodef:System category="intermediate">



Moriarty                     Standards Track                   [Page 48]

RFC 6545                           RID                        April 2012


             <iodef:Node>
               <iodef:Address category="ipv4-addr">192.0.2.3
               </iodef:Address>
             </iodef:Node>
           </iodef:System>
         </iodef:Flow>
       </iodef:EventData>
     </iodef:EventData>
     <iodef:EventData>
       <iodef:Flow>
         <iodef:System category="source">
           <iodef:Node>
             <iodef:Address category="ipv4-addr">192.0.2.35
             </iodef:Address>
           </iodef:Node>
           <iodef:Service ip_protocol="6">
             <iodef:Port>38765</iodef:Port>
           </iodef:Service>
         </iodef:System>
         <iodef:System category="target">
           <iodef:Node>
             <iodef:Address category="ipv4-addr">192.0.2.67
             </iodef:Address>
           </iodef:Node>
           <iodef:Service ip_protocol="6">
             <iodef:Port>80</iodef:Port>
           </iodef:Service>
         </iodef:System>
       </iodef:Flow>
       <iodef:Expectation severity="high" action="rate-limit-host">
         <iodef:Description>
           Rate-limit traffic close to source
         </iodef:Description>
       </iodef:Expectation>
       <iodef:Record>
         <iodef:RecordData>
           <iodef:Description>
             The IPv4 packet included was used in the described attack
           </iodef:Description>
           <iodef:RecordItem dtype="ipv4-packet">450000522ad9
           0000ff06c41fc0a801020a010102976d0050103e020810d9
           4a1350021000ad6700005468616e6b20796f7520666f7220
           6361726566756c6c792072656164696e6720746869732052
           46432e0a
           </iodef:RecordItem>
         </iodef:RecordData>
       </iodef:Record>
     </iodef:EventData>



Moriarty                     Standards Track                   [Page 49]

RFC 6545                           RID                        April 2012


     <iodef:History>
       <iodef:HistoryItem action="rate-limit-host">
         <iodef:DateTime>2004-02-02T22:53:01+00:00</iodef:DateTime>
         <iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
           CSIRT-FOR-OUR-DOMAIN#207-1
         </iodef:IncidentID>
         <iodef:Description>
           Notification sent to next upstream SP closer to 192.0.2.35
         </iodef:Description>
       </iodef:HistoryItem>
       <iodef:HistoryItem action="rate-limit-host">
         <iodef:DateTime>2004-02-02T23:07:21+00:00</iodef:DateTime>
         <iodef:IncidentID name="CSIRT-FOR-SP3">
           CSIRT-FOR-SP3#3291-1
         </iodef:IncidentID>
         <iodef:Description>
           Host rate-limited for 24 hours
           </iodef:Description>
         </iodef:HistoryItem>
       </iodef:History>
     </iodef:Incident>
     </iodef:IODEF-Document>
    </iodef-rid:XMLDocument>
<!-- End of IODEF-Document included in RID -->
  </iodef-rid:ReportSchema>
 </iodef-rid:RIDPolicy>
 <iodef-rid:IncidentSource>
   <iodef-rid:SourceFound>true</iodef-rid:SourceFound>
   <iodef:Node>
     <iodef:Address category="ipv4-addr">192.0.2.37</iodef:Address>
   </iodef:Node>
 </iodef-rid:IncidentSource>
</iodef-rid:RID>

7.2.  Investigation Request Communication Flow

  The diagram below outlines a RID Request communication flow between
  RID systems on different networks for a security incident with a
  known source address.  Therefore, MsgDestination is set to
  'InvestigationRequest' for the Request message and is included in the
  diagram below as "Investigation".  The proper response to a Request
  with the MsgDestination set to 'InvestigationRequest' is a Result
  message.  If there is a problem with the Request, such as a failure
  to validate the digital signature or decrypt the Request, an
  Acknowledgement message is sent to the requestor.  The
  Acknowledgement message should provide the reason why the message
  could not be processed.




Moriarty                     Standards Track                   [Page 50]

RFC 6545                           RID                        April 2012


      Attack Dest      SP-1              SP-2        Attack Src

      1. Attack    |  Attack
         reported  |  detected

      2.              Determine source
                      of security incident

      3.              o---Investigation---->

      4.                              Research
                                      incident and
                                      determine appropriate
                                      actions to take

      5.              <-------Result-------o

           Figure 9: Investigation Request Communication Flow

7.2.1.  Investigation Request Example

  The following example only includes the RID-specific details.  The
  IODEF and security measures are similar to the TraceRequest, with the
  exception that the source is known, the receiving RID system is known
  to be close to the source, and the MsgDestination is set to
  'InvestigationRequest'.  The source known is indicated in the IODEF
  document, which allows for incident sources to be listed as spoofed,
  if appropriate.

  This flow does not include a Result message because the request is
  denied as shown in the Acknowledgement response.

  SP-1 is represented by CERT-FOR-OUR-DOMAIN and 192.0.2.67.  SP-2 is
  identified by 192,0.2.98.  In this example, SP-2 is the service
  provider for systems on the 192.0.2.32/27 subnet.  The contact for
  the host 192.0.2.35 is known at the start of the request as
  '[email protected]'.

 <iodef-rid:RID lang="en"
                xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
                xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
   <iodef-rid:RIDPolicy MsgType="InvestigationRequest"
                        MsgDestination="SourceOfIncident">
     <iodef-rid:PolicyRegion region="PeerToPeer"/>
     <iodef:Node>
       <iodef:Address category="ipv4-addr">192.0.2.98</iodef:Address>
     </iodef:Node>
     <iodef-rid:TrafficType type="Attack"/>



Moriarty                     Standards Track                   [Page 51]

RFC 6545                           RID                        April 2012


     <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
       CERT-FOR-OUR-DOMAIN#208-1
     </iodef:IncidentID>
 <!-- IODEF-Document included in RID -->
     <iodef-rid:ReportSchema Version="1.0">
      <iodef-rid:XMLDocument dtype="xml" meaning="xml">
   <iodef:IODEF-Document lang="en">
   <iodef:Incident restriction="need-to-know" purpose="other">
     <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
       CERT-FOR-OUR-DOMAIN#208-1
     </iodef:IncidentID>
     <iodef:DetectTime>2004-02-05T08:13:33+00:00</iodef:DetectTime>
     <iodef:StartTime>2004-02-05T08:13:31+00:00</iodef:StartTime>
     <iodef:EndTime>2004-02-05T08:13:33+00:00</iodef:EndTime>
     <iodef:ReportTime>2004-02-05T08:13:35+00:00</iodef:ReportTime>
     <iodef:Description>Host involved in DoS attack</iodef:Description>
     <iodef:Assessment>
       <iodef:Impact severity="low" completion="failed" type="recon"/>
     </iodef:Assessment>
     <iodef:Contact role="creator" type="organization">
       <iodef:ContactName>Constituency-contact for 192.0.2.35
       </iodef:ContactName>
       <iodef:Email>[email protected]</iodef:Email>
     </iodef:Contact>
     <iodef:EventData>
       <iodef:Flow>
         <iodef:System category="source">
           <iodef:Node>
             <iodef:Address category="ipv4-addr">192.0.2.35
             </iodef:Address>
           </iodef:Node>
           <iodef:Service ip_protocol="6">
             <iodef:Port>41421</iodef:Port>
           </iodef:Service>
         </iodef:System>
         <iodef:System category="target">
           <iodef:Node>
             <iodef:Address category="ipv4-addr">192.0.2.67
             </iodef:Address>
           </iodef:Node>
           <iodef:Service ip_protocol="6">
             <iodef:Port>80</iodef:Port>
           </iodef:Service>
         </iodef:System>
       </iodef:Flow>
       <iodef:Expectation severity="high" action="investigate">
         <iodef:Description>
           Investigate whether source has been compromised



Moriarty                     Standards Track                   [Page 52]

RFC 6545                           RID                        April 2012


         </iodef:Description>
       </iodef:Expectation>
     </iodef:EventData>
     <iodef:History>
       <iodef:HistoryItem action="block-host">
         <iodef:DateTime>2004-02-05T08:19:01+00:00</iodef:DateTime>
         <iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
           CSIRT-FOR-OUR-DOMAIN#208-1
         </iodef:IncidentID>
         <iodef:Description>
           Investigation request sent to SP for 192.0.2.35
         </iodef:Description>
       </iodef:HistoryItem>
     </iodef:History>
   </iodef:Incident>
   </iodef:IODEF-Document>
      </iodef-rid:XMLDocument>
 <!-- End of IODEF-Document included in RID -->
     </iodef-rid:ReportSchema>
   </iodef-rid:RIDPolicy>
 </iodef-rid:RID>

7.2.2.  Acknowledgement Message Example

  The example Acknowledgement message is in response to the Request
  listed above.  The SP that received the request was unable to
  validate the digital signature used to authenticate the sending RID
  system.

  <iodef-rid:RID lang="en"
                 xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
                 xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
    <iodef-rid:RIDPolicy MsgType="Acknowledgement"
                         MsgDestination="RIDSystem">
      <iodef-rid:PolicyRegion region="IntraConsortium"/>
      <iodef:Node>
        <iodef:Address category="ipv4-addr">192.0.2.67</iodef:Address>
      </iodef:Node>
      <iodef-rid:TrafficType type="Attack"/>
      <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
        CERT-FOR-OUR-DOMAIN#208-1
      </iodef:IncidentID>
    </iodef-rid:RIDPolicy>
    <iodef-rid:RequestStatus AuthorizationStatus="Denied"
                             Justification="Authentication"/>
  </iodef-rid:RID>





Moriarty                     Standards Track                   [Page 53]

RFC 6545                           RID                        April 2012


7.3.  Report Communication Flow

  The diagram below outlines the RID Report communication flow between
  RID systems on different SPs.

          SP-1                           SP-2

       1. Generate incident information
          and prepare Report message

       2.              o-------Report------->

       3.                          File report in database

                  Figure 10: Report Communication Flow

  The Report communication flow is used to provide information on
  incidents.  Incident information may be shared between CSIRTs or
  other entities using this format.  When a report is received, the RID
  system must verify that the report has not already been filed.  The
  incident number and incident data, such as the hexadecimal packet and
  incident class information, can be used to compare with existing
  database entries.  The Report message typically does not have a
  response.  If there is a problem with the Report message, such as a
  failure to validate the digital signature [RFC3275] or decrypt the
  request, an Acknowledgement message is sent to the requestor.  The
  Acknowledgement message should provide the reason why the message
  could not be processed.

7.3.1.  Report Example

  The following example only includes the RID-specific details.  This
  report is an unsolicited Report message that includes an IPv4 packet.
  The IODEF document and digital signature is similar to the Request
  example with MsgDestination set to 'TraceRequest'.

  This example is a message sent from SP-1, CERT-FOR-OUR-DOMAIN at
  192.0.2.67, to SP-2 at 192.0.2.130 for informational purposes on an
  attack that took place.

  <iodef-rid:RID lang="en"
                 xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
                 xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
    <iodef-rid:RIDPolicy MsgType="Report" MsgDestination="RIDSystem">
      <iodef-rid:PolicyRegion region="PeerToPeer"/>
      <iodef:Node>
        <iodef:Address category="ipv4-addr">192.0.2.130</iodef:Address>
      </iodef:Node>



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      <iodef-rid:TrafficType type="Attack"/>
      <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
        CERT-FOR-OUR-DOMAIN#209-1
      </iodef:IncidentID>
  <!-- IODEF-Document included in RID -->
      <iodef-rid:ReportSchema>
       <iodef-rid:XMLDocument dtype="xml" meaning="xml">
    <iodef:IODEF-Document lang="en">
    <iodef:Incident restriction="need-to-know" purpose="reporting">
      <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
        CERT-FOR-OUR-DOMAIN#209-1
      </iodef:IncidentID>
      <iodef:DetectTime>2004-02-05T10:21:08+00:00</iodef:DetectTime>
      <iodef:StartTime>2004-02-05T10:21:05+00:00</iodef:StartTime>
      <iodef:EndTime>2004-02-05T10:35:00+00:00</iodef:EndTime>
      <iodef:ReportTime>2004-02-05T10:27:38+00:00</iodef:ReportTime>
      <iodef:Description>Host illicitly accessed admin account
      </iodef:Description>
      <iodef:Assessment>
        <iodef:Impact severity="high" completion="succeeded"
                      type="admin"/>
        <iodef:Confidence rating="high"/>
      </iodef:Assessment>
      <iodef:Contact role="creator" type="organization">
        <iodef:ContactName>Constituency-contact for 192.0.2.35
        </iodef:ContactName>
        <iodef:Email>[email protected]</iodef:Email>
      </iodef:Contact>
      <iodef:EventData>
        <iodef:Flow>
          <iodef:System category="source">
            <iodef:Node>
              <iodef:Address category="ipv4-addr">192.0.2.35
              </iodef:Address>
            </iodef:Node>
            <iodef:Service ip_protocol="6">
              <iodef:Port>32821</iodef:Port>
            </iodef:Service>
          </iodef:System>
          <iodef:System category="target">
            <iodef:Node>
              <iodef:Address category="ipv4-addr">192.0.2.67
              </iodef:Address>
            </iodef:Node>
            <iodef:Service ip_protocol="6">
              <iodef:Port>22</iodef:Port>
            </iodef:Service>
          </iodef:System>



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        </iodef:Flow>
      </iodef:EventData>
      <iodef:History>
        <iodef:HistoryItem action="rate-limit-host">
          <iodef:DateTime>2004-02-05T10:28:00+00:00</iodef:DateTime>
          <iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
            CSIRT-FOR-OUR-DOMAIN#209-1
          </iodef:IncidentID>
          <iodef:Description>
            Incident report sent to SP for 192.0.2.35
          </iodef:Description>
        </iodef:HistoryItem>
      </iodef:History>
    </iodef:Incident>
    </iodef:IODEF-Document>
       </iodef-rid:XMLDocument>
  <!-- End of IODEF-Document included in RID -->
    </iodef-rid:ReportSchema>
    </iodef-rid:RIDPolicy>
  </iodef-rid:RID>

7.4.  Query Communication Flow

  The diagram below outlines the RID Query communication flow between
  RID systems on different networks.

          SP-1                           SP-2

       1. Generate a request for
          information on a specific
          incident number or incident type

       2.              o-------Query------->

       3.                              Verify policy information
                                       and determine if matches exist
                                       for requested information

       4.              <-------Report------o

       5.  Associate report to request
           by incident number or type
           and file report(s).

                   Figure 11: Query Communication Flow

  The Query message communication receives a response of a Report
  message.  If the Report message is empty, the responding host did not



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  have information available to share with the requestor.  The incident
  number and responding RID system, as well as the transport, assist in
  the association of the request and response since a report can be
  filed and is not always solicited.  If there is a problem with the
  Query message, such as a failure to validate the digital signature or
  decrypt the request, an Acknowledgement message is sent to the
  requestor.  The Acknowledgement message should provide the reason why
  the message could not be processed.

7.4.1.  Query Example

  The Query request may be received in several formats as a result of
  the type of query being performed.  If the incident number is the
  only information provided, the IODEF document and IP packet data may
  not be needed to complete the request.  However, if a type of
  incident is requested, the incident number remains NULL, and the IP
  packet data will not be included in the IODEF RecordItem class; the
  other incident information is the main source for comparison.  In the
  case in which an incident number may not be the same between CSIRTs,
  the incident number and/or IP packet information can be provided and
  used for comparison on the receiving RID system to generate (a)
  Report message(s).

  This query is sent to 192.0.2.3, inquiring about the incident with
  the identifier CERT-FOR-OUR-DOMAIN#210-1.  The Report will be
  provided to the requestor identified and verified through the
  authentication and digital signature information provided in the RID
  message.  An example Report is provided above.

  <iodef-rid:RID lang="en"
                 xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
                 xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
    <iodef-rid:RIDPolicy MsgType="Query"
                         MsgDestination="RIDSystem">
      <iodef-rid:PolicyRegion region="PeerToPeer"/>
      <iodef:Node>
        <iodef:Address category="ipv4-addr">192.0.2.3</iodef:Address>
      </iodef:Node>
      <iodef-rid:TrafficType type="Attack"/>
      <iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
        CERT-FOR-OUR-DOMAIN#210-1
      </iodef:IncidentID>
    </iodef-rid:RIDPolicy>
  </iodef-rid:RID>







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8.  RID Schema Definition

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
 xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0"
 xmlns:xs="http://www.w3.org/2001/XMLSchema"
 xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
 targetNamespace="urn:ietf:params:xml:ns:iodef-rid-2.0"
 elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:import namespace="urn:ietf:params:xml:ns:iodef-1.0"
schemaLocation="http://www.iana.org/assignments/xml-registry/schema/
iodef-1.0.xsd"/>
<xs:import namespace="http://www.w3.org/2000/09/xmldsig#"
schemaLocation="http://www.w3.org/TR/xmldsig-core/
xmldsig-core-schema.xsd"/>

<!-- ****************************************************************
*********************************************************************
***  Real-time Inter-network Defense - RID XML Schema             ***
***    Namespace - iodef-rid, April 2012                        ***
***    The namespace is defined to support transport of IODEF     ***
***     documents for exchanging incident information.            ***
*********************************************************************
-->
<!--RID messages act as an envelope for IODEF and RID documents
    to support the exchange of incident information-->
<!--
====== Real-Time Inter-network Defense - RID ======
====  Suggested definition for RID messaging ======

 -->

<xs:annotation>
  <xs:documentation>XML Schema wrapper for IODEF</xs:documentation>
</xs:annotation>
<xs:element name="RID" type="iodef-rid:RIDType"/>
  <xs:complexType name="RIDType">
    <xs:sequence>
      <xs:element ref="iodef-rid:RIDPolicy" minOccurs="0"/>
      <xs:element ref="iodef-rid:RequestStatus" minOccurs="0"/>
      <xs:element ref="iodef-rid:IncidentSource" minOccurs="0"/>
    </xs:sequence>
    <xs:attribute name="lang"
                   type="xs:language" use="required"/>
  </xs:complexType>

<!--Used in Acknowledgement Message for RID-->




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<xs:element name="RequestStatus" type="iodef-rid:RequestStatusType"/>
  <xs:complexType name="RequestStatusType">
     <xs:attribute name="AuthorizationStatus" use="required">
        <xs:simpleType>
          <xs:restriction base="xs:NMTOKEN">
          <xs:whiteSpace value="collapse"/>
            <xs:enumeration value="Approved"/>
            <xs:enumeration value="Denied"/>
            <xs:enumeration value="Pending"/>
            <xs:enumeration value="ext-value"/>
          </xs:restriction>
        </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="ext-AuthorizationStatus"
                   type="xs:string" use="optional"/>
     <xs:attribute name="Justification">
        <xs:simpleType>
          <xs:restriction base="xs:NMTOKEN">
          <xs:whiteSpace value="collapse"/>
            <xs:enumeration value="SystemResource"/>
            <xs:enumeration value="Authentication"/>
            <xs:enumeration value="AuthenticationOrigin"/>
            <xs:enumeration value="Encryption"/>
            <xs:enumeration value="UnrecognizedFormat"/>
            <xs:enumeration value="CannotProcess"/>
            <xs:enumeration value="Other"/>
            <xs:enumeration value="ext-value"/>
          </xs:restriction>
        </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="ext-Justification"
                   type="xs:string" use="optional"/>
    <xs:attribute name="restriction" type="iodef:restriction-type"/>
  </xs:complexType>

<!--Incident Source Information for Result Message-->

<xs:element name="IncidentSource" type="iodef-rid:IncidentSourceType"/>
  <xs:complexType name="IncidentSourceType">
    <xs:sequence>
      <xs:element ref="iodef-rid:SourceFound"/>
      <xs:element ref="iodef:Node" minOccurs="0"
          maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="restriction" type="iodef:restriction-type"/>
  </xs:complexType>
  <xs:element name="SourceFound" type="xs:boolean"/>




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<!--
====== Real-Time Inter-network Defense Policy - RIDPolicy ======
======  Definition for RIDPolicy for messaging
 -->

<xs:annotation>
 <xs:documentation>RID Policy used for transport of
     messages</xs:documentation>
</xs:annotation>

<!-- RIDPolicy information with setting information listed in RID
     documentation -->

<xs:element name="RIDPolicy" type="iodef-rid:RIDPolicyType"/>
  <xs:complexType name="RIDPolicyType">
    <xs:sequence>
      <xs:element ref="iodef-rid:PolicyRegion" maxOccurs="unbounded"/>
      <xs:element ref="iodef:Node"/>
      <xs:element ref="iodef-rid:TrafficType" maxOccurs="unbounded"/>
      <xs:element ref="iodef:IncidentID" minOccurs="0"/>
      <xs:element ref="iodef-rid:ReportSchema" minOccurs="0"/>
    </xs:sequence>
   <xs:attribute name="MsgType" use="required">
    <xs:simpleType>
      <xs:restriction base="xs:NMTOKEN">
      <xs:whiteSpace value="collapse"/>
        <xs:enumeration value="TraceRequest"/>
        <xs:enumeration value="Acknowledgement"/>
        <xs:enumeration value="Result"/>
        <xs:enumeration value="InvestigationRequest"/>
        <xs:enumeration value="Report"/>
        <xs:enumeration value="Query"/>
        <xs:enumeration value="ext-value"/>
      </xs:restriction>
    </xs:simpleType>
   </xs:attribute>
  <xs:attribute name="ext-MsgType" type="xs:string" use="optional"/>
  <xs:attribute name="MsgDestination" use="required">
    <xs:simpleType>
      <xs:restriction base="xs:NMTOKEN">
      <xs:whiteSpace value="collapse"/>
        <xs:enumeration value="RIDSystem"/>
        <xs:enumeration value="SourceOfIncident"/>
        <xs:enumeration value="ext-value"/>
      </xs:restriction>
    </xs:simpleType>
   </xs:attribute>
  <xs:attribute name="ext-MsgDestination" type="xs:string"



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                use="optional"/>
  <xs:attribute name="restriction" type="iodef:restriction-type"/>
   </xs:complexType>
  <xs:element name="PolicyRegion">
    <xs:complexType>
     <xs:attribute name="region" use="required">
      <xs:simpleType>
       <xs:restriction base="xs:NMTOKEN">
       <xs:whiteSpace value="collapse"/>
         <xs:enumeration value="ClientToSP"/>
         <xs:enumeration value="SPToClient"/>
         <xs:enumeration value="IntraConsortium"/>
         <xs:enumeration value="PeerToPeer"/>
         <xs:enumeration value="BetweenConsortiums"/>
         <xs:enumeration value="ext-value"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="ext-region"
                   type="xs:string" use="optional"/>
    </xs:complexType>
  </xs:element>
  <xs:element name="TrafficType">
    <xs:complexType>
     <xs:attribute name="type" use="required">
      <xs:simpleType>
       <xs:restriction base="xs:NMTOKEN">
       <xs:whiteSpace value="collapse"/>
         <xs:enumeration value="Attack"/>
         <xs:enumeration value="Network"/>
         <xs:enumeration value="Content"/>
         <xs:enumeration value="DataWithHandlingRequirements"/>
         <xs:enumeration value="AudienceRestriction"/>
         <xs:enumeration value="Other"/>
         <xs:enumeration value="ext-value"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="ext-type"
                   type="xs:string" use="optional"/>
    </xs:complexType>
  </xs:element>
<!--Used to include an enveloped XML document in RID-->
<xs:element name="ReportSchema" type="iodef-rid:ReportSchemaType"/>
  <xs:complexType name="ReportSchemaType">
    <xs:sequence>
      <xs:element ref="iodef-rid:XMLDocument" minOccurs="1"
                  maxOccurs="1"/>



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      <xs:element ref="iodef-rid:URL" minOccurs="0"
                  maxOccurs="1"/>
      <xs:element ref="iodef-rid:Signature" minOccurs="0"
                  maxOccurs="unbounded"/>
    </xs:sequence>
     <xs:attribute name="Version" use="optional">
      <xs:simpleType>
       <xs:restriction base="xs:NMTOKEN">
       <xs:whiteSpace value="collapse"/>
         <xs:enumeration value="1.0"/>
              <xs:enumeration value="ext-value"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="ext-Version"
                   type="xs:string" use="optional"/>
     <xs:attribute name="XMLSchemaID" use="optional">
      <xs:simpleType>
       <xs:restriction base="xs:anyURI">
       <xs:whiteSpace value="collapse"/>
         <xs:enumeration value="urn:ietf:params:xml:ns:iodef-1.0"/>
              <xs:enumeration value="ext-value"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="ext-XMLSchemaID"
                   type="xs:string" use="optional"/>
    </xs:complexType>
  <xs:element name="XMLDocument"
              type="iodef:ExtensionType"/>
  <xs:element name="URL"
              type="xs:anyURI"/>
  <xs:element name="Signature"
              type="iodef:ExtensionType"/>
</xs:schema>

9.  Security Requirements

9.1.  XML Digital Signatures and Encryption

  RID leverages existing security standards and data markings in
  RIDPolicy to achieve the required levels of security for the exchange
  of incident information.  The use of standards includes TLS and the
  XML security features of encryption [XMLencrypt] and digital
  signatures [RFC3275] [XMLsig].  The standards provide clear methods
  to ensure that messages are secure, authenticated, and authorized;
  meet policy and privacy guidelines; and maintain integrity.  XML




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  Signature Best Practices [XMLSigBP] should be referenced by
  implementers for information on improving security to mitigate
  attacks.

  As specified in the relevant sections of this document, the XML
  digital signature [RFC3275] and XML encryption [XMLencrypt] are used
  in the following cases:

  XML Digital Signature

  o  The originator of a Request MUST use a detached signature to sign
     at least one of the original elements contained in the RecordItem
     class to provide authentication to all upstream participants in
     the trace or those involved in the investigation.  All instances
     of RecordItem provided by the originator may be individually
     signed, and additional RecordItem entries by upstream peers in the
     trace or investigation may be signed by the peer adding the data,
     while maintaining the original RecordItem entry(s) and detached
     signature(s) from the original requestor.  It is important to note
     that the data is signed at the RecordItem level.  Since multiple
     RecordItems may exist within an IODEF document and may originate
     from different sources, the signature is applied at the RecordItem
     level to enable the use of an XML detached signature.  Exclusive
     canonicalization [XMLCanon] is REQUIRED for the detached signature
     and not the references, as the XML document generated is then
     included in the RID message within the Signature element of the
     ReportSchema class.  This signature MUST be passed to all
     recipients of the Request message.

  o  If a Request does not include a RecordItem entry, a timestamp MUST
     be used to ensure there is data to be signed for the multi-hop
     authentication use case.  The DateTime element of the iodef:
     RecordData class ([RFC5070], Section 3.19.1) is used for this
     purpose.

  o  For all message types, the full IODEF-RID document MUST be signed
     using an enveloped signature by the sending peer to provide
     authentication and integrity to the receiving RID system.  The
     signature is placed in an instance of the Signature element.

  o  XML Signature Best Practices [XMLSigBP] guidance SHOULD be
     followed to prevent or mitigate security risks.  Examples include
     the recommendation to authenticate a signature prior to processing
     (executing potentially dangerous operations) and the
     recommendation to limit the use of URIs since they may enable
     cross-site scripting attacks or access to local information.





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  o  XML Path Language (XPath) 2.0 [XMLPath] MUST be followed to
     specify the portion of the XML document to be signed.  XPath is
     used to specify a location within an XML document.  Best practice
     recommendations for using XPath [XMLSigBP] SHOULD be referenced to
     reduce the risk of denial-of-service attacks.  The use of XSLT
     transforms MUST be restricted according to security guidance in
     [XMLSigBP].

  XML Encryption

  o  The IODEF-RID document MAY be encrypted to provide an extra layer
     of security between peers so that not only the message is
     encrypted for transport.  This behavior would be agreed upon
     between peers or a consortium, or determined on a per-message
     basis, depending on security requirements.  It should be noted
     that there are cases for transport where the RIDPolicy class needs
     to be presented in clear text, as detailed in the transport
     document [RFC6546].

  o  A Request, or any other message type that may be relayed through
     RID systems before reaching the intended destination as a result
     of trust relationships, MAY be encrypted specifically for the
     intended recipient.  This may be necessary if the RID network is
     being used for message transfer, the intermediate parties do not
     need to have knowledge of the request contents, and a direct
     communication path does not exist.  In that case, the RIDPolicy
     class is used by intermediate parties and as such, RIDPolicy is
     maintained in clear text.

  o  The action taken in the Result message may be encrypted using the
     key of the request originator.  In that case, the intermediate
     parties can view the RIDPolicy information and know the trace has
     been completed and do not need to see the action.  If the use of
     encryption were limited to sections of the message, the History
     class information would be encrypted.  Otherwise, it is
     RECOMMENDED to encrypt the entire IODEF-RID document and use an
     enveloped signature for the originator of the request.  The
     existence of the Result message for an incident would tell any
     intermediate parties used in the path of the incident
     investigation that the incident handling has been completed.

  o  The iodef:restriction attribute sets expectations for the privacy
     of an incident and is defined in Section 3.2 of RFC 5070.
     Following the guidance for XML encryption in the Security
     Requirements section, the iodef:restriction attribute can be set
     in any of the RID classes to define restrictions and encryption
     requirements for the exchange of incident information.  The
     restriction options enable encryption capabilities for the



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     complete exchange of an IODEF document (including any extensions),
     within specific classes of IODEF, or IODEF extensions, where more
     limited restrictions are desired.  The restriction attribute is
     contained in each of the RID classes and MUST be used in
     accordance with confidentiality expectations for either sections
     of the IODEF document or the complete IODEF document.  Consortiums
     and organizations should consider this guidance when creating
     exchange policies.

  o  Expectations based on how restriction is set:

     *  If restriction is set to 'private', the class or document MUST
        be encrypted for the recipient using XML encryption and the
        public key of the recipient.  See Section 9.3 for a discussion
        on public key infrastructure (PKI) and other security
        requirements.

     *  If restriction is set to 'need-to-know', the class or document
        MUST be encrypted to ensure only those with need-to-know access
        can decrypt the data.  The document can either be encrypted for
        each individual for which access is intended or be encrypted
        with a single group key.  The method used SHOULD adhere to any
        certificate policy and practices agreements between entities
        for the use of RID.  A group key in this instance refers to a
        single key (symmetric) that is used to encrypt the block of
        data.  The users with need-to-know access privileges may be
        given access to the shared key via a secure distribution
        method, for example, providing access to the symmetric key
        encrypted with each of the user's public keys.

     *  If restriction is set to 'public', the class or document MUST
        be sent in clear text.  This setting can be critical if certain
        sections of a document or an entire document are to be shared
        without restrictions.  This provides flexibility within an
        incident to share certain information freely where appropriate.

     *  If restriction is set to 'default', the information can be
        shared according to an information disclosure policy pre-
        arranged by the communicating parties.

  o  Expectations based on placement of the restriction setting:

     *  If restriction is set within one of the RID classes, the
        restriction applies to the entire IODEF document.

     *  If restriction is set within individual IODEF classes, the
        restriction applies to the specific IODEF class and the
        children of that class.



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  The formation of policies is a very important aspect of using a
  messaging system like RID to exchange potentially sensitive
  information.  Many considerations should be involved for peering
  parties, and some guidelines to protect the data, systems, and
  transport are covered in this section.  Policies established should
  provide guidelines for communication methods, security, and fall-back
  procedures.  See Sections 9.4 and 9.5 for additional information on
  consortiums and PKI considerations.

  The security considerations for the storage and exchange of
  information in RID messaging may include adherence to local,
  regional, or national regulations in addition to the obligations to
  protect client information during an investigation.  RIDPolicy is a
  necessary tool for listing the requirements of messages to provide a
  method to categorize data elements for proper handling.  Controls are
  also provided for the sending entity to protect messages from third
  parties through XML encryption.

  RID provides a method to exchange incident-handling requests and
  Report messages between entities.  Administrators have the ability to
  base decisions on the available resources and other factors of their
  network and maintain control of incident investigations within their
  own network.  Thus, RID provides the ability for participating
  networks to manage their own security controls, leveraging the
  information listed in RIDPolicy.

  RID is used to transfer or exchange XML documents in an IODEF format
  or using another IANA-registered format.  Implementations SHOULD NOT
  download schemas at runtime due to the security implications, and
  included documents MUST NOT be required to provide a resolvable
  location of their schema.

9.2.  Message Transport

  A transport specification is defined in a separate document
  [RFC6546].  The specified transport protocols MUST use encryption to
  provide an additional level of security and integrity, while
  supporting mutual authentication through bidirectional certificate
  usage.  Any subsequent transport method defined should take advantage
  of existing standards for ease of implementation and integration of
  RID systems.  Session encryption for the transport of RID messages is
  enforced in the transport specification.  The privacy and security
  considerations are addressed fully in RID to protect sensitive
  portions of documents and to provide a method to authenticate the
  messages.  Therefore, RID messages do not rely on the security
  provided by the transport layer alone.  The encryption requirements
  and considerations for RID messages are discussed in Section 9.1 of
  this document.



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  Consortiums may vary their selected transport mechanisms and thus
  decide upon a mutual protocol to use for transport when communicating
  with peers in a neighboring consortium using RID.  RID systems MUST
  implement and deploy HTTPS as defined in the transport document
  [RFC6546] and optionally MAY support other protocols such as the
  Blocks Extensible Exchange Protocol (BEEP) [RFC3080].  Bindings would
  need to be defined to enable support for other transport protocols.

  Systems used to send authenticated RID messages between networks MUST
  use a secured system and interface to connect to a border network's
  RID systems.  Each connection to a RID system MUST meet the security
  requirements agreed upon through the consortium regulations, peering,
  or SLAs.  The RID system MUST listen for and send RID messages on
  only the designated port, which also MUST be over an encrypted tunnel
  meeting the minimum requirement of algorithms and key lengths
  established by the consortium, peering, or SLA.  The selected
  cryptographic algorithms for symmetric encryption, digital
  signatures, and hash functions MUST meet minimum security levels of
  the times.  The encryption strength MUST adhere to import and export
  regulations of the involved countries for data exchange.

  Out-of-band communications dedicated to SP interaction for RID
  messaging would provide additional security as well as guaranteed
  bandwidth during a denial-of-service attack.  For example, an out-of-
  band channel may consist of logical paths defined over the existing
  network.  Out-of-band communications may not be practical or possible
  between service providers, but provisions should be considered to
  protect the incident management systems used for RID messaging.
  Methods to protect the data transport may also be provided through
  session encryption.

9.3.  Public Key Infrastructure

  It is RECOMMENDED that RID, the XML security functions, and transport
  protocols properly integrate with a PKI managed by the consortium,
  federate PKIs within a consortium, or use a PKI managed by a trusted
  third party.  Entities MAY use shared keys as an alternate solution,
  although this may limit the ability to validate certificates and
  could introduce risk.  For the Internet, a few examples of existing
  efforts that could be leveraged to provide the supporting PKI include
  the Regional Internet Registry's (RIR's) PKI hierarchy, vendor issued
  certificates, or approved issuers of Extended Validation (EV)
  Certificates.  Security and privacy considerations related to
  consortiums are discussed in Sections 9.4 and 9.5.

  The use of PKI between entities or by a consortium SHOULD adhere to
  any applicable certificate policy and practices agreements for the
  use of RID.  [RFC3647] specifies a commonly used format for



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  certificate policy (CP) and certification practices statements (CPS).
  Systems with predefined relationships for RID include those who peer
  directly or through a consortium with agreed-upon appropriate use
  agreements.  The agreements to trust other entities may be based on
  assurance levels that could be determined by a comparison of the CP,
  CPS, and/or RID operating procedures.  The initial comparison of
  policies and the ability to audit controls provide a baseline
  assurance level for entities to form and maintain trust
  relationships.  Trust relationships may also be defined through a
  bridged or hierarchical PKI in which both peers belong.  If shared
  keys or keys issued from a common CA are used, the verification of
  controls to determine the assurance level to trust other entities may
  be limited to the RID policies and operating procedures.

  XML security functions utilized in RID require a trust center such as
  a PKI for the distribution of credentials to provide the necessary
  level of security for this protocol.  Layered transport protocols
  also utilize encryption and rely on a trust center.  Public key
  certificate pairs issued by a trusted Certification Authority (CA)
  MAY be used to provide the necessary level of authentication and
  encryption for the RID protocol.  The CA used for RID messaging must
  be trusted by all involved parties and may take advantage of similar
  efforts, such as the Internet2 federated PKI or the ARIN/RIR effort
  to provide a PKI to service providers.  The PKI used for
  authentication also provides the necessary certificates needed for
  encryption used for the RID transport protocol [RFC6546].

9.3.1.  Authentication

  Hosts receiving a RID message MUST be able to verify that the sender
  of the request is valid and trusted.  Using digital signatures on a
  hash of the RID message with an X.509 version 3 certificate issued by
  a trusted party MUST be used to authenticate the request.  The X.509
  version 3 specifications as well as the digital signature
  specifications and path validation standards set forth in [RFC5280]
  MUST be followed in order to interoperate with a PKI designed for
  similar purposes.  Full path validation verifies the chaining
  relationship to a trusted root and also performs a certificate
  revocation check.  The use of digital signatures in RID XML messages
  MUST follow the World Wide Web Consortium (W3C) recommendations for
  signature syntax and processing when either the XML encryption
  [XMLencrypt] or digital signature [XMLsig] [RFC3275] is used within a
  document.








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  It might be helpful to define an extension to the authentication
  scheme that uses attribute certificates [RFC5755] in such a way that
  an application could automatically determine whether human
  intervention is needed to authorize a request; however, the
  specification of such an extension is out of scope for this document.

  The use of pre-shared keys may be considered for authentication at
  the transport layer.  If this option is selected, the specifications
  set forth in "Pre-Shared Key Ciphersuites for Transport Layer
  Security (TLS)" [RFC4279] MUST be followed.  Transport specifications
  are detailed in a separate document [RFC6546].

9.3.2.  Multi-Hop Request Authentication

  The use of multi-hop authentication in a Request is used when a
  Request is sent to multiple entities or SPs in an iterative manner.
  Multi-hop authentication is REQUIRED in Requests that involve
  multiple SPs where Requests are forwarded iteratively through peers.
  Bilateral trust relationships MAY be used between peers; multi-hop
  authentication MUST be used for cases where the originator of a
  message is authenticated several hops into the message flow.

  For practical reasons, SPs may want to prioritize incident-handling
  events based upon the immediate peer for a Request, the originator of
  a request, and the listed Confidence rating for the incident.  In
  order to provide a higher assurance level of the authenticity of a
  Request, the originating RID system is included in the Request along
  with contact information and the information of all RID systems in
  the path the trace has taken.  This information is provided through
  the IODEF EventData class, which nests the list of systems and
  contacts involved in a trace, while setting the category attribute to
  "infrastructure".

  To provide multi-hop authentication, the originating RID system MUST
  include a digital signature in the Request sent to all systems in the
  upstream path.  The digital signature from the RID system is
  performed on the RecordItem class of the IODEF following the XML
  digital signature specifications from W3C [XMLsig] using a detached
  signature.  The signature MUST be passed to all parties that receive
  a Request, and each party MUST be able to perform full path
  validation on the digital signature [RFC5280].  In order to
  accommodate that requirement, the RecordItem data MUST remain
  unchanged as a request is passed along between providers and is the
  only element for which the signature is applied.  If additional
  RecordItems are included in the document at upstream peers, the
  initial RecordItem entry MUST still remain with the detached
  signature.  The subsequent RecordItem elements may be signed by the
  peer adding the incident information for the investigation.  A second



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  benefit to this requirement is that the integrity of the filter used
  is ensured as it is passed to subsequent SPs in the upstream trace of
  the incident.  The trusted PKI also provides the keys used to
  digitally sign the RecordItem class for a Request to meet the
  requirement of authenticating the original request.  Any host in the
  path of the trace should be able to verify the digital signature
  using the trusted PKI.

  In the case in which an enterprise using RID sends a Request to its
  provider, the signature from the enterprise MUST be included in the
  initial request.  The SP may generate a new request to send upstream
  to members of the SP consortium to continue the investigation.  If
  the original request is sent, the originating SP, acting on behalf of
  the enterprise network under attack, MUST also digitally sign, with
  an enveloped signature, the full IODEF document to assure the
  authenticity of the Request.  An SP that offers RID as a service may
  be using its own PKI to secure RID communications between its RID
  system and the attached enterprise networks.  SPs participating in
  the trace MUST be able to determine the authenticity of RID requests.

9.4.  Consortiums and Public Key Infrastructures

  Consortiums are an ideal way to establish a communication web of
  trust for RID messaging.  It should be noted that direct
  relationships may be ideal for some communications, such as those
  between a provider of incident information and a subscriber of the
  incident reports.  The consortium could provide centralized
  resources, such as a PKI, and established guidelines and control
  requirements for use of RID.  The consortium may assist in
  establishing trust relationships between the participating SPs to
  achieve the necessary level of cooperation and experience-sharing
  among the consortium entities.  This may be established through PKI
  certificate policy [RFC3647] reviews to determine the appropriate
  trust levels between organizations or entities.  The consortium may
  also be used for other purposes to better facilitate communication
  among SPs in a common area (Internet, region, government, education,
  private networks, etc.).

  Using a PKI to distribute certificates used by RID systems provides
  an already established method to link trust relationships between
  consortiums that peer with SPs belonging to a separate consortium.
  In other words, consortiums could peer with other consortiums to
  enable communication of RID messages between the participating SPs.
  The PKI along with Memorandums of Agreement could be used to link
  border directories to share public key information in a bridge, a
  hierarchy, or a single cross-certification relationship.





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  Consortiums also need to establish guidelines for each participating
  SP to adhere to.  The RECOMMENDED guidelines include:

  o  Physical and logical practices to protect RID systems;

  o  Network- and application-layer protection for RID systems and
     communications;

  o  Proper use guidelines for RID systems, messages, and requests; and

  o  A PKI, certificate policy, and certification practices statement
     to provide authentication, integrity, and privacy.

  The functions described for a consortium's role parallel those of a
  PKI federation.  The PKI federations that currently exist are
  responsible for establishing security guidelines and PKI trust
  models.  The trust models are used to support applications to share
  information using trusted methods and protocols.

  A PKI can also provide the same level of security for communication
  between an end entity (enterprise, educational, or government
  customer network) and the SP.

9.5.  Privacy Concerns and System Use Guidelines

  Privacy issues raise many concerns when information-sharing is
  required to achieve the goal of stopping or mitigating the effects of
  a security incident.  The RIDPolicy class is used to automate the
  enforcement of the privacy concerns listed within this document.  The
  privacy and system use concerns for the system communicating RID
  messages and other integrated components include the following:

  Service Provider Concerns:

  o  Privacy of data monitored and/or stored on Intrusion Detection
     Systems (IDSs) for attack detection.

  o  Privacy of data monitored and stored on systems used to trace
     traffic across a single network.

  o  Privacy of incident information stored on incident management
     systems participating in RID communications.

  Customer Attached Networks Participating in RID with SP:

  o  Customer networks may include enterprise, educational, government,
     or other networks attached to an SP participating in RID.
     Customers should review data handling policies to understand how



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     data will be protected by a service provider.  This information
     will enable customers to decide what types of data at what
     sensitivity level can be shared with service providers.  This
     information could be used at the application layer to establish
     sharing profiles for entities and groups; see Section 9.6.

  o  Customers should request information on the security and privacy
     considerations in place by their SP and the consortium of which
     the SP is a member.  Customers should understand if their data
     were to be forwarded, how it might be sanitized and how it will be
     protected.  In advance of sharing data with their SP, customers
     should also understand if limitations can be placed on how it will
     be used.

  o  Customers should be aware that their data can and will be sent to
     other SPs in order to complete a trace unless an agreement stating
     otherwise is made in the service level agreements between the
     customer and SP.  Customers considering privacy options may limit
     the use of this feature if they do not want the data forwarded.

  Parties Involved in the Attack:

  o  Privacy of the identity of a host involved in an attack or any
     indicators of compromise.

  o  Privacy of information such as the source and destination used for
     communication purposes over the monitored or RID-connected
     network(s).

  o  Protection of data from being viewed by intermediate parties in
     the path of an Request request should be considered.

  Consortium Considerations:

  o  System use restrictions for security incident handling within the
     local region's definitions of appropriate traffic.  When
     participating in a consortium, appropriate use guidelines should
     be agreed upon and entered into contracts.

  o  System use prohibiting the consortium's participating SPs from
     inappropriately tracing traffic to locate sources or mitigate
     traffic unlawfully within the jurisdiction or region.

  Inter-Consortium Considerations:

  o  System use between peering consortiums should consider any
     government communication regulations that apply between those two
     regions, such as encryption export and import restrictions.



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  o  System use between consortiums SHOULD NOT request traffic traces
     and actions beyond the scope intended and permitted by law or
     inter-consortium agreements.

  o  System use between consortiums should consider national boundary
     issues and request limits in their appropriate system use
     agreements.  Appropriate use should include restrictions to
     prevent the use of the protocol for limiting or restricting
     traffic that is otherwise permitted within the country in which
     the peering consortium resides.

  The security and privacy considerations listed above are for the
  consortiums, SPs, and enterprises to agree upon.  The agreed-upon
  policies may be facilitated through use of the RIDPolicy class and
  application-layer options.  Some privacy considerations are addressed
  through the RID guidelines for encryption and digital signatures as
  described in Section 9.1.

  RID is useful in determining the true source of an incident that
  traverses multiple networks or to communicate security incidents and
  automate the response.  The information obtained from the
  investigation may determine the identity of the source host or the SP
  used by the source of the traffic.  It should be noted that the trace
  mechanism used across a single SP may also raise privacy concerns for
  the clients of the network.  Methods that may raise concern include
  those that involve storing packets for some length of time in order
  to trace packets after the fact.  Monitoring networks for intrusions
  and for tracing capabilities also raises concerns for potentially
  sensitive valid traffic that may be traversing the monitored network.
  IDSs and single-network tracing are outside of the scope of this
  document, but the concern should be noted and addressed within the
  use guidelines of the network.  Some IDSs and single-network trace
  mechanisms attempt to properly address these issues.  RID is designed
  to provide the information needed by any single-network trace
  mechanism.  The provider's choice of a single trace mechanism depends
  on resources, existing solutions, and local legislation.  Privacy
  concerns in regard to the single-network trace must be dealt with at
  the client-to-SP level and are out of scope for RID messaging.

  The identity of the true source of an attack being traced through RID
  could be sensitive.  The true identity listed in a Result message can
  be protected through the use of encryption [XMLencrypt] enveloping
  the IODEF document and RID Result information, using the public
  encryption key of the originating SP.  Alternatively, the action
  taken may be listed without the identity being revealed to the
  originating SP.  The ultimate goal of the RID communication system is
  to stop or mitigate attack traffic, not to ensure that the identity
  of the attack traffic is known to involved parties.  The SP that



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  identifies the source should deal directly with the involved parties
  and proper authorities in order to determine the guidelines for the
  release of such information, if it is regarded as sensitive.  In some
  situations, systems used in attacks are compromised by an unknown
  source and, in turn, are used to attack other systems.  In that
  situation, the reputation of a business or organization may be at
  stake, and the action taken may be the only additional information
  reported in the Result message to the originating system.  If the
  security incident is a minor incident, such as a zombie system used
  in part of a large-scale DDoS attack, ensuring the system is taken
  off the network until it has been fixed may be sufficient.  The
  decision is left to the system users and consortiums to determine
  appropriate data to be shared given that the goal of the
  specification is to provide the appropriate technical options to
  remain compliant.  The textual descriptions should include details of
  the incident in order to protect the reputation of the unknowing
  attacker and prevent the need for additional investigation.  Local,
  state, or national laws may dictate the appropriate reporting action
  for specific security incidents.

  Privacy becomes an issue whenever sensitive data traverses a network.
  For example, if an attack occurred between a specific source and
  destination, then every SP in the path of the trace becomes aware
  that the cyber attack occurred.  In a targeted attack, it may not be
  desirable that information about two nation states that are battling
  a cyber war would become general knowledge to all intermediate
  parties.  However, it is important to allow the traces to take place
  in order to halt the activity since the health of the networks in the
  path could also be at stake during the attack.  This provides a
  second argument for allowing the Result message to only include an
  action taken and not the identity of the offending host.  In the case
  of a Request or Report, where the originating SP is aware of the SP
  that will receive the request for processing, the free-form text
  areas of the document could be encrypted [XMLencrypt] using the
  public key of the destination SP to ensure that no other SP in the
  path can read the contents.  The encryption is accomplished through
  the W3C [XMLencrypt] specification for encrypting an element.

  In some situations, all network traffic of a nation may be granted
  through a single SP.  In that situation, options must support sending
  Result messages from a downstream peer of that SP.  That option
  provides an additional level of abstraction to hide the identity and
  the SP of the identified source of the traffic.  Legal action may
  override this technical decision after the trace has taken place, but
  that is out of the technical scope of this document.






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  Privacy concerns when using an Request message to request action
  close to the source of valid attack traffic need to be considered.
  Although the intermediate SPs may relay the request if there is no
  direct trust relationship to the closest SP to the source, the
  intermediate SPs do not require the ability to see the contents of
  the packet or the text description field(s) in the request.  This
  message type does not require any action by the intermediate RID
  systems, except to relay the packet to the next SP in the path.
  Therefore, the contents of the request may be encrypted for the
  destination system.  The intermediate SPs only need to know how to
  direct the request to the manager of the ASN in which the source IP
  address belongs.

  Traces must be legitimate security-related incidents and not used for
  purposes such as sabotage or censorship.  An example of such abuse of
  the system includes a request to block or rate-limit legitimate
  traffic to prevent information from being shared between users on the
  Internet (restricting access to online versions of papers) or
  restricting access from a competitor's product in order to sabotage a
  business.

  Intra-consortium RID communications raise additional issues,
  especially when the peering consortiums reside in different regions
  or nations.  Request messages and requested actions to mitigate or
  stop traffic must adhere to the appropriate use guidelines and yet
  prevent abuse of the system.  First, the peering consortiums must
  identify the types of traffic that can be traced between the borders
  of the participating SPs of each consortium.  The traffic traced
  should be limited to security-incident-related traffic.  Second, the
  traces permitted within one consortium, if passed to a peering
  consortium, may infringe upon the peering consortium's freedom-of-
  information laws.  An example would be a consortium in one country
  permitting a trace of traffic containing objectionable material,
  outlawed within that country.  The RID trace may be a valid use of
  the system within the confines of that country's network border;
  however, it may not be permitted to continue across network
  boundaries where such content is permitted under law.  By continuing
  the trace in another country's network, the trace and response could
  have the effect of improperly restricting access to data.  A
  continued trace into a second country may break the laws and
  regulations of that nation.  Any such traces MUST cease at the
  country's border.

  The privacy concerns listed in this section address issues among the
  trusted parties involved in a trace within an SP, a RID consortium,
  and peering RID consortiums.  Data used for RID communications must
  also be protected from parties that are not trusted.  This protection
  is provided through the authentication and encryption of documents as



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  they traverse the path of trusted servers and through the local
  security controls in place for the incident management systems.  Each
  RID system MUST perform a bidirectional authentication when sending a
  RID message and use the public encryption key of the upstream or
  downstream peer to send a message or document over the network.  This
  means that the document is decrypted and re-encrypted at each RID
  system via TLS over a transport protocol such as [RFC6546].  The RID
  messages may be decrypted at each RID system in order to properly
  process the request or relay the information.  Today's processing
  power is more than sufficient to handle the minimal burden of
  encrypting and decrypting relatively small typical RID messages.

9.6.  Sharing Profiles and Policies

  The application layer can be used to establish workflows and rulesets
  specific to sharing profiles for entities or consortiums.  The
  profiles can leverage sharing agreements to restrict data types or
  classifications of data that are shared.  The level of information or
  classification of data shared with any entity may be based on
  protection levels offered by the receiving entity and periodic
  validation of those controls.  The profile may also indicate how far
  information can be shared according to the entity and data type.  The
  profile may also indicate whether requests to share data from an
  entity must go directly to that entity.

  In some cases, pre-defined sharing profiles will be possible.  These
  include any use case where an agreement is in place in advance of
  sharing.  Examples may be between clients and SPs, entities such as
  partners, or consortiums.  There may be other cases when sharing
  profiles may not be established in advance, such as an organization
  dealing with an incident who requires assistance from an entity that
  it has not worked with before.  An organization may want to establish
  sharing profiles specific to possible user groups to prepare for
  possible incident scenarios.  The user groups could include business
  partners, industry peers, service providers, experts not part of a
  service provider, law enforcement, or regulatory reporting bodies.

  Workflows to approve transactions may be specific to sharing profiles
  and data types.  Application developers should include capabilities
  to enable these decision points for users of the system.

  Any expectations between entities to preserve the weight and
  admissibility of evidence should be handled at the policy and
  agreement level.  A sharing profile may include notes or an indicator
  for approvers in workflows to reflect if such agreements exist.






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10.  Security Considerations

  RID has many security requirements and considerations built into the
  design of the protocol, several of which are described in the
  Security Requirements section.  For a complete view of security,
  considerations include the availability, confidentiality, and
  integrity concerns for the transport, storage, and exchange of
  information.

  Protected tunnels between systems accepting RID communications are
  used to provide confidentiality, integrity, authenticity, and privacy
  for the data at the transport layer.  Encryption and digital
  signatures are also used at the IODEF document level through RID
  options to provide confidentiality, integrity, authenticity, privacy
  and traceability of the document contents at the application layer.
  Trust relationships are based on PKI and the comparison/validation of
  security controls for the incident management systems communicating
  via RID.  Trust levels can be established in cross-certification
  processes where entities compare PKI policies that include the
  specific management and handling of an entity's PKI and certificates
  issued under that policy.  [RFC3647] defines an Internet X.509 Public
  Key Infrastructure Certificate Policy and Certification Practices
  Framework that may be used in the comparison of policies to establish
  trust levels and agreements between entities, an entity and a
  consortium, and consortiums.  The agreements SHOULD consider key
  management practices including the ability to perform path validation
  on certificates [RFC5280], key distribution techniques [RFC2585], and
  Certificate Authority and Registration Authority management
  practices.

  The agreements between entities SHOULD also include a common
  understanding of the usage of RID security, policy, and privacy
  options discussed in both the Security Requirements and Security
  Considerations sections.  The formality, requirements, and complexity
  of the agreements for the certificate policy, practices, supporting
  infrastructure, and the use of RID options SHOULD be decided by the
  entities or consortiums creating those agreements.

11.  Internationalization Issues

  The Node class identifies a host or network device.  This document
  reuses the definition of Node from the IODEF specification [RFC5070],
  Section 3.16.  However, that document did not clearly specify whether
  a NodeName could be an Internationalized Domain Name (IDN).  RID
  systems MUST treat the NodeName class as a domain name slot
  [RFC5890].  RID systems SHOULD support IDNs in the NodeName class.
  If they do so, the UTF-8 representation of the domain name MUST be
  used, i.e., all of the domain name's labels MUST be U-labels



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  expressed in UTF-8 or NR-LDH labels [RFC5890]; A-labels MUST NOT be
  used.  An application communicating via RID can convert between
  A-labels and U-labels by using the Punycode encoding [RFC3492] for
  A-labels as described in the protocol specification for
  Internationalized Domain Names in Applications [RFC5891].

12.  IANA Considerations

  This document uses URNs to describe XML namespaces and XML schemas
  [XMLschema] conforming to a registry mechanism described in
  [RFC3688].

  Registration request for the iodef-rid namespace:

     URI: urn:ietf:params:xml:ns:iodef-rid-2.0

     Registrant Contact: IESG.

     XML: None.  Namespace URIs do not represent an XML specification.

  Registration request for the iodef-rid XML schema:

     URI: urn:ietf:params:xml:schema:iodef-rid-2.0

     Registrant Contact: IESG.

     XML: See Section 8, "RID Schema Definition", of this document.

  The following registry has been created and is now managed by IANA:

     Name of the registry: "XML Schemas Exchanged via RID"

     Namespace details: A registry entry for an XML Schema Transferred
     via RID consists of:

        Schema Name: A short string that represents the schema
        referenced.  This value is for reference only in the table.
        The version of the schema MUST be included in this string to
        allow for multiple versions of the same specification to be in
        the registry.

        Version: The version of the registered XML schema.  The version
        is a string that SHOULD be formatted as numbers separated by a
        '.' (period) character.







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        Namespace: The namespace of the referenced XML schema.  This is
        represented in the RID ReportSchema class in the XMLSchemaID
        attribute as an enumerated value is represented by a URN or
        URI.

        Specification URI: A URI [RFC3986] from which the registered
        specification can be obtained.  The specification MUST be
        publicly available from this URI.

        Reference: The reference to the document that describes the
        schema.

     Information that must be provided to assign a new value: The above
     list of information.

     Fields to record in the registry: Schema Name, Version, Namespace,
     Specification URI, Reference

     Initial registry contents: See Section 5.6.1.

     Allocation Policy: Expert Review [RFC5226] and Specification
     Required [RFC5226].

  The Designated Expert is expected to consult with the MILE (Managed
  Incident Lightweight Exchange) working group or its successor if any
  such WG exists (e.g., via email to the working group's mailing list).
  The Designated Expert is expected to retrieve the XML schema
  specification from the provided URI in order to check the public
  availability of the specification and verify the correctness of the
  URI.  An important responsibility of the Designated Expert is to
  ensure that the XML schema is appropriate for use in RID.

  The following registry has been created and is now managed by IANA:

     Name of the registry: "RID Enumeration List"

     The registry is intended to enable enumeration value additions to
     attributes in the iodef-rid XML schema.

     Fields to record in the registry: Attribute Name, Attribute Value,
     Description, Reference

     Initial registry content: none.

     Allocation Policy: Expert Review [RFC5226]






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  The Designated Expert is expected to consult with the MILE (Managed
  Incident Lightweight Exchange) working group or its successor if any
  such WG exists (e.g., via email to the working group's mailing list).
  The Designated Expert is expected to review the request and validate
  the appropriateness of the enumeration for the attribute.  If a
  specification is associated with the request, it MUST be reviewed by
  the Designated Expert.

13.  Summary

  Security incidents have always been difficult to trace as a result of
  spoofed sources, resource limitations, and bandwidth utilization
  problems.  Incident response is often slow even when the IP address
  is known to be valid because of the resources required to notify the
  responsible party of the attack and then to stop or mitigate the
  attack traffic.  Methods to identify and trace attacks near real time
  are essential to thwarting attack attempts.  SPs need policies and
  automated methods to combat the hacker's efforts.  SPs need automated
  monitoring and response capabilities to identify and trace attacks
  quickly without resource-intensive side effects.  Integration with a
  centralized communication system to coordinate the detection,
  tracing, and identification of attack sources on a single network is
  essential.  RID provides a way to integrate SP resources for each
  aspect of attack detection, tracing, and source identification and
  extends the communication capabilities among SPs.  The communication
  is accomplished through the use of flexible IODEF XML-based documents
  passed between incident-handling systems or RID systems.  A Request
  is communicated to an upstream SP and may result in an upstream trace
  or in an action to stop or mitigate the attack traffic.  The messages
  are communicated among peers with security inherent to the RID
  messaging scheme provided through existing standards such as XML
  encryption and digital signatures.  Policy information is carried in
  the RID message itself through the use of the RIDPolicy.  RID
  provides the timely communication among SPs, which is essential for
  incident handling.

14.  References

14.1.  Normative References

  [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
                Requirement Levels", BCP 14, RFC 2119, March 1997.

  [RFC2585]     Housley, R. and P. Hoffman, "Internet X.509 Public Key
                Infrastructure Operational Protocols: FTP and HTTP",
                RFC 2585, May 1999.





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  [RFC3023]     Murata, M., St. Laurent, S., and D. Kohn, "XML Media
                Types", RFC 3023, January 2001.

  [RFC3275]     Eastlake, D., Reagle, J., and D. Solo, "(Extensible
                Markup Language) XML-Signature Syntax and Processing",
                RFC 3275, March 2002.

  [RFC3470]     Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines
                for the Use of Extensible Markup Language (XML)
                within IETF Protocols", BCP 70, RFC 3470, January 2003.

  [RFC3492]     Costello, A., "Punycode: A Bootstring encoding of
                Unicode for Internationalized Domain Names in
                Applications (IDNA)", RFC 3492, March 2003.

  [RFC3688]     Mealling, M., "The IETF XML Registry", BCP 81,
                RFC 3688, January 2004.

  [RFC4051]     Eastlake, D., "Additional XML Security Uniform Resource
                Identifiers (URIs)", RFC 4051, April 2005.

  [RFC4279]     Eronen, P. and H. Tschofenig, "Pre-Shared Key
                Ciphersuites for Transport Layer Security (TLS)",
                RFC 4279, December 2005.

  [RFC5070]     Danyliw, R., Meijer, J., and Y. Demchenko, "The
                Incident Object Description Exchange Format", RFC 5070,
                December 2007.

  [RFC5226]     Narten, T. and H. Alvestrand, "Guidelines for Writing
                an IANA Considerations Section in RFCs", BCP 26,
                RFC 5226, May 2008.

  [RFC5280]     Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
                Housley, R., and W. Polk, "Internet X.509 Public Key
                Infrastructure Certificate and Certificate Revocation
                List (CRL) Profile", RFC 5280, May 2008.

  [RFC5646]     Phillips, A. and M. Davis, "Tags for Identifying
                Languages", BCP 47, RFC 5646, September 2009.

  [RFC5755]     Farrell, S., Housley, R., and S. Turner, "An Internet
                Attribute Certificate Profile for Authorization",
                RFC 5755, January 2010.

  [RFC5890]     Klensin, J., "Internationalized Domain Names for
                Applications (IDNA): Definitions and Document
                Framework", RFC 5890, August 2010.



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  [RFC5891]     Klensin, J., "Internationalized Domain Names in
                Applications (IDNA): Protocol", RFC 5891, August 2010.

  [RFC6546]     Trammell, B., "Transport of Real-time Inter-network
                Defense (RID) Messages over HTTP/TLS", RFC 6546,
                April 2012.

  [XML1.0]      Bray, T., Maler, E., Paoli, J., Sperberg-McQueen, C.,
                and F. Yergeau, "Extensible Markup Language (XML) 1.0",
                W3C Recommendation XML 1.0, November 2008,
                <http://www.w3.org/TR/xml/>.

  [XMLCanon]    Boyer, J., "Canonical XML 1.0", W3C Recommendation 1.0,
                December 2001, <http://www.w3.org/TR/xml-c14n>.

  [XMLPath]     Berglund, A., Boag, S., Chamberlin, D., Fernandez, M.,
                Kay, M., Robie, J., and J. Simeon, "XML Schema Part 1:
                Structures", W3C Recommendation Second Edition,
                December 2010, <http://www.w3.org/TR/xpath20/>.

  [XMLSigBP]    Hirsch, F. and P. Datta, "XML-Signature Best
                Practices", W3C Recommendation, August 2011,
                <http://www.w3.org/TR/xmldsig-bestpractices/>.

  [XMLencrypt]  Imaura, T., Dillaway, B., and E. Simon, "XML Encryption
                Syntax and Processing", W3C Recommendation,
                December 2002, <http://www.w3.org/TR/xmlenc-core/>.

  [XMLschema]   Thompson, H., Beech, D., Maloney, M., and N.
                Mendelsohn, "XML Schema Part 1: Structures", W3C
                Recommendation Second Edition, October 2004,
                <http://www.w3.org/TR/xmlschema-1/>.

  [XMLsig]      Bartel, M., Boyer, J., Fox, B., LaMaccia, B., and E.
                Simon, "XML-Signature Syntax and Processing", W3C
                Recommendation Second Edition, June 2008,
                <http://www.w3.org/TR/xmldsig-core/>.

14.2.  Informative References

  [RFC1930]     Hawkinson, J. and T. Bates, "Guidelines for creation,
                selection, and registration of an Autonomous System
                (AS)", BCP 6, RFC 1930, March 1996.

  [RFC3080]     Rose, M., "The Blocks Extensible Exchange Protocol
                Core", RFC 3080, March 2001.





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  [RFC3647]     Chokhani, S., Ford, W., Sabett, R., Merrill, C., and S.
                Wu, "Internet X.509 Public Key Infrastructure
                Certificate Policy and Certification Practices
                Framework", RFC 3647, November 2003.

  [RFC3986]     Berners-Lee, T., Fielding, R., and L. Masinter,
                "Uniform Resource Identifier (URI): Generic Syntax",
                STD 66, RFC 3986, January 2005.

  [RFC5735]     Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses",
                BCP 153, RFC 5735, January 2010.

  [RFC6045]     Moriarty, K., "Real-time Inter-network Defense (RID)",
                RFC 6045, November 2010.

  [RFC6194]     Polk, T., Chen, L., Turner, S., and P. Hoffman,
                "Security Considerations for the SHA-0 and SHA-1
                Message-Digest Algorithms", RFC 6194, March 2011.

  [XMLNames]    Bray, T., Hollander, D., Layman, A., Tobin, R., and H.
                Thomson, "Namespaces in XML 1.0 (Third Edition)", W3C
                Recommendation , December 2009,
                <http://www.w3.org/TR/xml-names/>.




























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Appendix A.  Acknowledgements

  Many thanks to colleagues and the Internet community for reviewing
  and commenting on the document as well as providing recommendations
  to improve, simplify, and secure the protocol: Steve Bellovin, David
  Black, Harold Booth, Paul Cichonski, Robert K. Cunningham, Roman
  Danyliw, Yuri Demchenko, Sandra G. Dykes, Stephen Farrell, Katherine
  Goodier, Cynthia D. McLain, Thomas Millar, Jean-Francois Morfin,
  Stephen Northcutt, Damir Rajnovic, Tony Rutkowski, Peter Saint-Andre,
  Jeffrey Schiller, Robert Sparks, William Streilein, Richard Struse,
  Tony Tauber, Brian Trammell, Sean Turner, Iljitsch van Beijnum, and
  David Waltermire.

Author's Address

  Kathleen M. Moriarty
  EMC Corporation
  176 South Street
  Hopkinton, MA
  United States

  EMail: [email protected]





























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