Internet Engineering Task Force (IETF)                             J. Yi
Request for Comments: 7985                                    T. Clausen
Updates: 7186                                        Ecole Polytechnique
Category: Informational                                       U. Herberg
ISSN: 2070-1721                                            November 2016


      Security Threats to Simplified Multicast Forwarding (SMF)

Abstract

  This document analyzes security threats to Simplified Multicast
  Forwarding (SMF), including vulnerabilities of duplicate packet
  detection and relay set selection mechanisms.  This document is not
  intended to propose solutions to the threats described.

  In addition, this document updates RFC 7186 regarding threats to the
  relay set selection mechanisms using the Mobile Ad Hoc Network
  (MANET) Neighborhood Discovery Protocol (NHDP) (RFC 6130).

Status of This Memo

  This document is not an Internet Standards Track specification; it is
  published for informational purposes.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It has been approved for publication by the Internet
  Engineering Steering Group (IESG).  Not all documents approved by the
  IESG are a candidate for any level of Internet Standard; see
  Section 2 of RFC 7841.

  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/rfc7985.

















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Copyright Notice

  Copyright (c) 2016 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
  2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
  3.  SMF Threat Overview . . . . . . . . . . . . . . . . . . . . .   4
  4.  Threats to Duplicate Packet Detection . . . . . . . . . . . .   5
    4.1.  Attack on the Hop Limit Field . . . . . . . . . . . . . .   6
    4.2.  Threats to Identification-Based Duplicate Packet
          Detection . . . . . . . . . . . . . . . . . . . . . . . .   7
      4.2.1.  Pre-Activation Attacks (Pre-Play) . . . . . . . . . .   7
      4.2.2.  De-activation Attacks (Sequence Number Wrangling) . .   8
    4.3.  Threats to Hash-Based Duplicate Packet Detection  . . . .   9
      4.3.1.  Attack on the Hash-Assistant Value  . . . . . . . . .   9
  5.  Threats to Relay Set Selection  . . . . . . . . . . . . . . .  10
    5.1.  Common Threats to Relay Set Selection . . . . . . . . . .  10
    5.2.  Threats to the E-CDS Algorithm  . . . . . . . . . . . . .  10
      5.2.1.  Link Spoofing . . . . . . . . . . . . . . . . . . . .  11
      5.2.2.  Identity Spoofing . . . . . . . . . . . . . . . . . .  11
    5.3.  Threats to S-MPR Algorithm  . . . . . . . . . . . . . . .  11
    5.4.  Threats to the MPR-CDS Algorithm  . . . . . . . . . . . .  12
  6.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
  7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
    7.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
    7.2.  Informative References  . . . . . . . . . . . . . . . . .  13
  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  15
  Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15










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1.  Introduction

  This document analyzes security threats to Simplified Multicast
  Forwarding (SMF) [RFC6621].  SMF aims at providing basic Internet
  Protocol (IP) multicast forwarding in a way that is suitable for
  wireless mesh and Mobile Ad Hoc Networks (MANET).  SMF consists of
  two major functional components: duplicate packet detection (DPD) and
  relay set selection (RSS).

  SMF is typically used in decentralized wireless environments and is
  potentially exposed to various attacks and misconfigurations.  In a
  wireless environment, some of these attacks and misconfigurations
  represent threats of particular significance as compared to what they
  would do in wired networks.  [RFC6621] briefly discusses several of
  these, but does not define any explicit security measures for
  protecting the integrity of the protocol.

  This document is based on the assumption that no additional security
  mechanism, such as IPsec, is used in the IP layer, as not all MANET
  deployments may be able to support deployment of such common IP
  protection mechanisms (e.g., because MANET routers may have limited
  resources for supporting the IPsec stack).  It also assumes that
  there is no lower-layer protection.  The document analyzes possible
  attacks on, and misconfigurations of, SMF and outlines the
  consequences of such attacks/misconfigurations to the state
  maintained by SMF in each router.

  In the Security Considerations section of [RFC6621], denial-of-
  service-attack scenarios are briefly discussed.  This document
  further analyzes and describes the potential vulnerabilities of, and
  attack vectors for, SMF.  While completeness in such analysis is
  always a goal, no claims of being complete are made.  The goal of
  this document is to be helpful when deploying SMF in a network and
  for understanding the risks incurred, as well as for providing a
  reference to and documented experience with SMF as input for possible
  future developments of SMF.

  This document is not intended to propose solutions to the threats
  described.  [RFC7182] provides a framework that can be used with SMF,
  and depending on how it is used, may offer some degree of protection
  against the threats related to identity spoofing described in this
  document.

  This document also updates [RFC7186], specifically with respect to
  threats to relay set selection (RSS) mechanisms that are using MANET
  NHDP [RFC6130].





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2.  Terminology

  This document uses the terminology and notation defined in [RFC5444],
  [RFC6130], [RFC6621], and [RFC4949].

  Additionally, this document introduces the following terminology:

  SMF router:  A MANET router, running SMF as specified in [RFC6621].

  Attacker:  A device that is present in the network and intentionally
     seeks to compromise the information bases in SMF routers.  It may
     generate syntactically correct SMF control messages.

  Legitimate SMF router:  An SMF router that is correctly configured
     and not compromised by an attacker.

3.  SMF Threat Overview

  An SMF router requires an external dynamic neighborhood discovery
  mechanism in order to maintain suitable topological information
  describing its immediate neighborhood, and thereby allowing it to
  select reduced relay sets for forwarding multicast data traffic.
  Such an external dynamic neighborhood discovery mechanism may be
  provided by lower-layer interface information, by a concurrently
  operating MANET routing protocol that already maintains such
  information (e.g., [RFC7181]) or by explicitly using the MANET
  Neighborhood Discovery Protocol (NHDP) [RFC6130].  If NHDP is used
  for both 1-hop and 2-hop neighborhood discovery by SMF, SMF
  implicitly inherits the vulnerabilities of NHDP discussed in
  [RFC7186].  As SMF relies on NHDP to assist in network-layer 2-hop
  neighborhood discovery (no matter if other lower-layer mechanisms are
  used for 1-hop neighborhood discovery), this document assumes that
  NHDP is used in SMF.  The threats that are NHDP specific are
  indicated explicitly.

  Based on neighborhood discovery mechanisms, [RFC6621] specifies two
  principal functional components: duplicate packet detection (DPD) and
  relay set selection (RSS).

  DPD is required by SMF in order to be able to detect duplicate
  packets and eliminate their redundant forwarding.  An attacker has
  two ways in which to harm the DPD mechanisms.  Specifically, it can:

  o  "deactivate" DPD, making it such that duplicate packets are not
     correctly detected.  As a consequence, they are (redundantly)
     transmitted, which increases the load on the network, drains the
     batteries of the routers involved, etc.




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  o  "pre-activate" DPD, making DPD detect a later arriving (valid)
     packet as being a duplicate and will, therefore, not be forwarded.

  Attacks on DPD can be achieved by replaying existing packets,
  wrangling sequence numbers, manipulating hash values, etc.; these are
  detailed in Section 4.

  RSS produces a reduced relay set for forwarding multicast data
  packets across a MANET.  For use in SMF, [RFC6621] specifies several
  relay set algorithms including E-CDS (Essential Connected Dominating
  Set) [RFC5614], S-MPR (Source-Based Multipoint Relay, as known from
  [RFC3626] and [RFC7181]), and MPR-CDS (Multipoint Relay Connected
  Dominating Set) [MPR-CDS].  An attacker can disrupt the RSS
  algorithm, and thereby the SMF operation, by degrading it to
  classical flooding or by "masking" certain parts of the network from
  the multicasting domain.  Attacks on RSS algorithms are detailed in
  Section 5.

  Other than the attacks on DPD and RSS, a common vulnerability of
  MANETs is "jamming", i.e., a device generates massive amounts of
  interfering radio transmissions, which will prevent legitimate
  traffic (e.g., control traffic as well as data traffic) on part of a
  network.  The attacks on DPD and RSS can be further enhanced by
  jamming.

4.  Threats to Duplicate Packet Detection

  Duplicate packet detection (DPD) is required for packet dissemination
  in MANETs because: (1) packets may be retransmitted via the same
  physical interface as the one over which they were received, and (2)
  a router may receive multiple copies of the same packet (on the same
  or on different interfaces) from different neighbors.  DPD is thus
  used to check whether or not an incoming packet has been previously
  received.

  DPD is achieved by maintaining a record of recently processed
  multicast packets, and comparing later received multicast packets
  herewith.  A duplicate packet detected is silently dropped and is not
  inserted into the forwarding path of that router, nor is it delivered
  to an application.  DPD, as proposed by SMF, supports both IPv4 and
  IPv6 and suggests two duplicate packet detection mechanisms for each:
  1) IP packet header content identification-based DPD (I-DPD), in
  combination with flow state, to estimate temporal uniqueness of a
  packet, and 2) hash-based DPD (H-DPD), employing hashing of selected
  IP packet header fields and payload for the same effect.






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  In the Security Considerations section of [RFC6621], a selection of
  threats to DPD are briefly introduced.  This section expands on that
  discussion and describes how to effectively launch the attacks on DPD
  -- for example, by way of manipulating jitter and/or the Hash-
  Assistant Value.  In the remainder of this section, common threats to
  packet detection mechanisms are discussed first; then, the threats to
  I-DPD and H-DPD are introduced separately.  The threats described in
  this section are applicable to general SMF implementations,
  regardless of whether NHDP is used.

4.1.  Attack on the Hop Limit Field

  One immediate Denial-of-Service (DoS) attack is based on manipulating
  the Time-to-Live (TTL, for IPv4) or Hop Limit (for IPv6) field.  As
  routers only forward packets with TTL > 1, an attacker can forward an
  otherwise valid packet while drastically reducing the TTL hereof.
  This will inhibit recipient routers from later forwarding the same
  multicast packet, even if received with a different TTL --
  essentially, an attacker can thus instruct its neighbors to block the
  forwarding of valid multicast packets.

  For example, in Figure 1, router A forwards a multicast packet with a
  TTL of 64 to the network.  A, B, and C are legitimate SMF routers,
  and X is an attacker.  In a wireless environment, jitter is commonly
  used to avoid systematic collisions in Media Access Control (MAC)
  protocols [RFC5148].  An attacker can thus increase the probability
  that its invalid packets arrive first by retransmitting them without
  applying jitter.  In this example, router X forwards the packet
  without applying jitter and reduces the TTL to 1.  Router C thus
  records the duplicate detection value (hash value for H-DPD or the
  header content of the packets for I-DPD) but does not forward the
  packet (due to TTL == 1).  When a second copy of the same packet,
  with a non-maliciously manipulated TTL value (63 in this case),
  arrives from router B, it will be discarded as a duplicate packet.

                                .---.
                                | X |
                              --'---' __
       packet with TTL=64    /          \  packet with TTL=1
                            /            \
                        .---.              .---.
                        | A |              | C |
                        '---'              '---'
       packet with TTL=64   \    .---.   /
                             \-- | B |__/  packet with TTL=63
                                 '---'

                                Figure 1



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  As the TTL of a packet is intended to be manipulated by
  intermediaries forwarding it, classic methods such as integrity check
  values (e.g., digital signatures) are typically calculated by setting
  TTL fields to some predetermined value (e.g., 0) -- for example, the
  case for IPsec Authentication Headers -- rendering such an attack
  more difficult to both detect and counter.

  If the attacker has access to a "wormhole" through the network (a
  directional antenna, a tunnel to a collaborator, or a wired
  connection, allowing it to bridge parts of a network otherwise
  distant), it can make sure that the packets with such an artificially
  reduced TTL arrive before their unmodified counterparts.

4.2.  Threats to Identification-Based Duplicate Packet Detection

  I-DPD uses a specific DPD identifier in the packet header to identify
  a packet.  By default, such packet identification is not provided by
  the IP packet header (for both IPv4 and IPv6).  Therefore, additional
  identification headers, such as the fragment header, a hop-by-hop
  header option, or IPsec sequencing, must be employed in order to
  support I-DPD.  The uniqueness of a packet can then be identified by
  the source IP address of the packet originator and the sequence
  number (from the fragment header, hop-by-hop header option, or
  IPsec).  By doing so, each intermediate router can keep a record of
  recently received packets and determine whether or not the incoming
  packet has been received.

4.2.1.  Pre-Activation Attacks (Pre-Play)

  In a wireless environment, or across any other shared channel, an
  attacker can perceive the identification tuple (source IP address,
  sequence number) of a packet.  It is possible to generate a packet
  with the same (source IP address, sequence number) pair with invalid
  content.  If the sequence number progression is predictable, then it
  is trivial to generate and inject invalid packets with "future"
  identification information into the network.  If these invalid
  packets arrive before the legitimate packets that they are spoofing,
  the latter will be treated as a duplicate and will be discarded.
  This can prevent multicast packets from reaching parts of the
  network.

  Figure 2 gives an example of a pre-activation attack.  A, B, and C
  are legitimate SMF routers, and X is the attacker.  The line between
  the routers presents the packet forwarding.  Router A is the source
  and originates a multicast packet with sequence number n.  When
  router X receives the packet, it generates an invalid packet with the
  source address of A and sequence number n.  If the invalid packet
  arrives at router C before the forwarding of router B, the valid



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  packet will be dropped by C as a duplicate packet.  An attacker can
  manipulate jitter to make sure that the invalid packets arrive first.
  Router X can even generate packets with future sequence numbers (if
  they are predictable), so that the future legitimate packets with the
  same sequence numbers will be dropped as duplicate ones.

                                .---.
                                | X |
                              --'---' __
       packet with seq=n     /          \  invalid packet with seq=n
                            /            \
                        .---.              .---.
                        | A |              | C |
                        '---'              '---'
       packet with seq=n    \    .---.   /
                             \-- | B |__/  valid packet with seq=n
                                 '---'

                                Figure 2

  As SMF does not currently have any timestamp mechanisms to protect
  data packets, there is no viable way to detect such pre-play attacks
  by way of timestamps.  Especially, if the attack is based on
  manipulation of jitter, the validation of the timestamp would not be
  helpful because the timing is still valid (but, much less valuable).

4.2.2.  De-activation Attacks (Sequence Number Wrangling)

  An attacker can also seek to de-activate DPD by modifying the
  sequence number in packets that it forwards.  Thus, routers will not
  be able to detect an actual duplicate packet as a duplicate --
  rather, they will treat them as new packets, i.e., process and
  forward them.  This is similar to DoS attacks, as each packet that is
  considered unique will be multicasted: for a network with n routers,
  there will be n-1 retransmissions.  This can easily cause the
  "broadcast storm" problem discussed in [MOBICOM99].  The consequence
  of this attack is an increased channel load, the origin of which
  appears to be a router other than the attacker.

  Given the topology shown in Figure 2, on receiving a packet with
  seq=n, the attacker X can forward the packet with a modified sequence
  number n+i.  This has two consequences: firstly, router C will not be
  able to detect that the packet forwarded by X is a duplicate packet;
  secondly, the consequent packet with seq=n+i generated by router A
  will probably be treated as a duplicate packet and will be dropped by
  router C.





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4.3.  Threats to Hash-Based Duplicate Packet Detection

  When explicit sequence numbers in packet headers is undesired, hash-
  based DPD can be used.  A hash of the non-mutable fields in the
  header of the data payload can be generated and recorded at the
  intermediate routers.  A packet can thus be uniquely identified by
  the source IP address of the packet and its hash-value.

  The hash algorithm used by SMF is being applied only to provide a
  reduced probability of collision and is not being used for
  cryptographic or authentication purposes.  Consequently, a digest
  collision is still possible.  In case the source router or gateway
  identifies that it has recently generated or injected a packet with
  the same hash-value, it inserts a "Hash-Assist Value (HAV)" IPv6
  header option into the packet, such that also calculating the hash
  over this HAV will render the resulting value unique.

4.3.1.  Attack on the Hash-Assistant Value

  The HAV header is helpful when a digest collision happens.  However,
  it also introduces a potential vulnerability.  As the HAV option is
  only added when the source or the ingress SMF router detects that the
  incoming packet has digest collision with previously generated
  packets, it can actually be regarded as a "flag" of potential digest
  collision.  An attacker can discover the HAV header and be able to
  conclude that a hash collision is possible if the HAV header is
  removed.  By doing so, the modified packet received by other SMF
  routers will be treated as duplicate packets and will be dropped
  because they have the same hash value as previously received packets.

  In the example shown in Figure 3, routers A and B are legitimate SMF
  routers; X is an attacker.  Router A generates two packets, P1 and
  P2, with the same hash value h(P1)=h(P2)=x.  Based on the SMF
  specification, a HAV is added to the latter packet P2, so that
  h(P2+HAV)=x' avoids digest collision.  When the attacker X detects
  the HAV of P2, it is able to conclude that a collision is possible by
  removing the HAV header.  By doing so, packet P2 will be treated as a
  duplicate packet by router B and will be dropped.

             P2            P1                P2         P1
  .---.  h(P2+HAV)=x'    h(P1)=x    .---.  h(P2)=x     h(P1)=x    .---.
  | A |---------------------------> | X | ----------------------> | B |
  `---'                             `---'                         `---'

                                Figure 3






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5.  Threats to Relay Set Selection

  A framework for an RSS mechanism, rather than a specific RSS
  algorithm, is provided by SMF.  Relay Set Selection is normally
  achieved by distributed algorithms that can dynamically generate a
  topological Connected Dominating Set based on 1-hop and 2-hop
  neighborhood information.  In this section, common threats to the RSS
  framework are first discussed.  Then specific threats to the three
  algorithms (Essential Connection Dominating Set (E-CDS), Source-Based
  Multipoint Relay (S-MPR), and Multipoint Relay Connected Dominating
  Set (MPR-CDS)) explicitly enumerated by [RFC6621] are analyzed.  As
  the relay set selection is based on 1-hop and 2-hop neighborhood
  information, which rely on NHDP, the threats described in this
  section are NHDP specific.

5.1.  Common Threats to Relay Set Selection

  Non-algorithm-specific threats to RSS algorithms, including DoS
  attacks, eavesdropping, message timing attacks, and broadcast storm,
  are discussed in [RFC7186].

5.2.  Threats to the E-CDS Algorithm

  The "Essential Connected Dominating Set" (E-CDS) algorithm [RFC5614]
  forms a single CDS mesh for an SMF operating region.  This algorithm
  requires 2-hop neighborhood information (the identity of the
  neighbors, the link to the neighbors, and the neighbors' priority
  information), as collected through NHDP or another process.

  An SMF router will select itself as a relay, if:

  o  The SMF router has a higher priority than all of its symmetric
     neighbors, or

  o  A path from the neighbor with the largest priority to any other
     neighbor via neighbors with greater priority than the current
     router does not exist.

  An attacker can disrupt the E-CDS algorithm by link spoofing or
  identity spoofing.











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5.2.1.  Link Spoofing

  Link spoofing implies that an attacker advertises non-existing links
  to another router (which may or may not be present in the network).

  An attacker can declare itself to have high route priority and spoof
  the links to as many legitimate SMF routers as possible to declare
  high connectivity.  By doing so, it can prevent legitimate SMF
  routers from selecting themselves as relays.  As the "super" relay in
  the network, the attacker can manipulate the traffic it relays.

5.2.2.  Identity Spoofing

  Identity spoofing implies that an attacker determines and makes use
  of the identity of other legitimate routers, without being authorized
  to do so.  The identity of other routers can be obtained by
  eavesdropping the control messages or the source/destination address
  from datagrams.  The attacker can then generate control or datagram
  traffic by pretending to be a legitimate router.

  Because E-CDS self-selection is based on the router priority value,
  an attacker can spoof the identity of other legitimate routers and
  declare a different router priority value.  If it declares that a
  spoofed router has a higher priority, it can prevent other routers
  from selecting themselves as relays.  On the other hand, if the
  attacker declares that a spoofed router has a lower priority, it can
  force other routers to select themselves as relays to degrade the
  multicast forwarding to classical flooding.

5.3.  Threats to S-MPR Algorithm

  The S-MPR set selection algorithm enables individual routers, using
  2-hop topology information, to select relays from among their set of
  neighboring routers.  MPRs are selected by each router such that a
  message generated by it, and relayed only by its MPRs, will reach all
  of its 2-hop neighbors.

  An SMF router forwards a multicast packet if and only if:

  o  the packet has not been received before, and

  o  the neighbor from which the packet was received has selected the
     router as MPR.

  Because MPR calculation is based on the willingness declared by the
  SMF routers and the connectivity of the routers, it can be disrupted
  by both link spoofing and identity spoofing.  These threats and their
  impacts have been illustrated in Section 5.1 of [RFC7186].



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5.4.  Threats to the MPR-CDS Algorithm

  MPR-CDS is a derivative from S-MPR.  The main difference between
  S-MPR and MPR-CDS is that while S-MPR forms a different broadcast
  tree for each source in the network, MPR-CDS forms a unique broadcast
  tree for all sources in the network.

  As MPR-CDS combines E-CDS and S-MPR and the simple combination of the
  two algorithms does not address the weaknesses; the vulnerabilities
  of E-CDS and S-MPR that are discussed in Sections 5.2 and 5.3 apply
  to MPR-CDS also.

6.  Security Considerations

  This document does not specify a protocol or a procedure.  The whole
  document, however, reflects on security considerations for SMF
  regarding packet dissemination in MANETs.  Possible attacks to the
  two main functional components of SMF, duplicate packet detection,
  and relay set selection are analyzed and documented.

  Although neither [RFC6621] nor this document propose mechanisms to
  secure the SMF protocol, there are several possibilities to secure
  the protocol in the future and drive new work by suggesting which
  threats discussed in the previous sections could be addressed.

  For the I-DPD mechanism, employing randomized packet sequence numbers
  can avoid some pre-activation attacks based on sequence number
  prediction.  If predicable sequence numbers have to be used, applying
  timestamps can mitigate pre-activation attacks.

  For the H-DPD mechanism, applying cryptographically strong hashes can
  make the digest collisions effectively impossible, and it can avoid
  the use of a HAV.

  [RFC7182] specifies a framework for representing cryptographic
  Integrity Check Values (ICVs) and timestamps in MANETs.  Based on
  [RFC7182], [RFC7183] specifies integrity and replay protection for
  NHDP using shared keys as a mandatory-to-implement security
  mechanism.  If SMF is using NHDP as the neighborhood discovery
  protocol, implementing [RFC7183] remains advisable so as to enable
  integrity protection for NHDP control messages.  This can help
  mitigate threats related to identity spoofing through the exchange of
  HELLO messages and provide some general protection against identity
  spoofing by admitting only trusted routers to the network using ICVs
  in HELLO messages.






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  Using ICVs does not, of course, address the problem of attackers able
  to also generate valid ICVs.  Detection and exclusion of such
  attackers is, in general, a challenge that is not unrelated to how
  [RFC7182] is used.  If, for example, it is used with a shared key (as
  per [RFC7183]), excluding single attackers generally is not aided by
  the use of ICVs.  However, if routers have sufficient capabilities to
  support the use of asymmetric keys (as per [RFC7859]), part of
  addressing this challenge becomes one of providing key revocation in
  a way that does not in itself introduce additional vulnerabilities.

  As [RFC7183] does not protect the integrity of the multicast user
  datagram, and as no mechanism is specified by SMF for doing so,
  duplicate packet detection remains vulnerable to the threats
  introduced in Section 4.

  If pre-activation/de-activation attacks and attacks on the HAV of the
  multicast datagrams are to be mitigated, a datagram-level integrity
  protection mechanism is desired, by taking consideration of the
  identity field or HAV.  However, this would not be helpful for the
  attacks on the TTL (or Hop Limit for IPv6) field, because the mutable
  fields are generally not considered when ICV is calculated.

7.  References

7.1.  Normative References

  [RFC6130]  Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
             Network (MANET) Neighborhood Discovery Protocol (NHDP)",
             RFC 6130, DOI 10.17487/RFC6130, April 2011,
             <http://www.rfc-editor.org/info/rfc6130>.

  [RFC6621]  Macker, J., Ed., "Simplified Multicast Forwarding",
             RFC 6621, DOI 10.17487/RFC6621, May 2012,
             <http://www.rfc-editor.org/info/rfc6621>.

  [RFC7186]  Yi, J., Herberg, U., and T. Clausen, "Security Threats for
             the Neighborhood Discovery Protocol (NHDP)", RFC 7186,
             DOI 10.17487/RFC7186, April 2014,
             <http://www.rfc-editor.org/info/rfc7186>.

7.2.  Informative References

  [MOBICOM99]
             Ni, S., Tseng, Y., Chen, Y., and J. Sheu, "The broadcast
             storm problem in a mobile ad hoc network", MobiCom
             '99 Proceedings of the 5th annual ACM/IEEE international
             conference on Mobile computing and networking,
             DOI 10.1145/313451.313525, 1999.



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  [MPR-CDS]  Adjih, C., Jacquet, P., and L. Viennot, "Computing
             Connected Dominating Sets with Multipoint Relays", Journal
             of Ad Hoc and Sensor Wireless Networks 2002, January 2002.

  [RFC3626]  Clausen, T., Ed. and P. Jacquet, Ed., "Optimized Link
             State Routing Protocol (OLSR)", RFC 3626,
             DOI 10.17487/RFC3626, October 2003,
             <http://www.rfc-editor.org/info/rfc3626>.

  [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2",
             FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
             <http://www.rfc-editor.org/info/rfc4949>.

  [RFC5148]  Clausen, T., Dearlove, C., and B. Adamson, "Jitter
             Considerations in Mobile Ad Hoc Networks (MANETs)",
             RFC 5148, DOI 10.17487/RFC5148, February 2008,
             <http://www.rfc-editor.org/info/rfc5148>.

  [RFC5444]  Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
             "Generalized Mobile Ad Hoc Network (MANET) Packet/Message
             Format", RFC 5444, DOI 10.17487/RFC5444, February 2009,
             <http://www.rfc-editor.org/info/rfc5444>.

  [RFC5614]  Ogier, R. and P. Spagnolo, "Mobile Ad Hoc Network (MANET)
             Extension of OSPF Using Connected Dominating Set (CDS)
             Flooding", RFC 5614, DOI 10.17487/RFC5614, August 2009,
             <http://www.rfc-editor.org/info/rfc5614>.

  [RFC7181]  Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
             "The Optimized Link State Routing Protocol Version 2",
             RFC 7181, DOI 10.17487/RFC7181, April 2014,
             <http://www.rfc-editor.org/info/rfc7181>.

  [RFC7182]  Herberg, U., Clausen, T., and C. Dearlove, "Integrity
             Check Value and Timestamp TLV Definitions for Mobile Ad
             Hoc Networks (MANETs)", RFC 7182, DOI 10.17487/RFC7182,
             April 2014, <http://www.rfc-editor.org/info/rfc7182>.

  [RFC7183]  Herberg, U., Dearlove, C., and T. Clausen, "Integrity
             Protection for the Neighborhood Discovery Protocol (NHDP)
             and Optimized Link State Routing Protocol Version 2
             (OLSRv2)", RFC 7183, DOI 10.17487/RFC7183, April 2014,
             <http://www.rfc-editor.org/info/rfc7183>.

  [RFC7859]  Dearlove, C., "Identity-Based Signatures for Mobile Ad Hoc
             Network (MANET) Routing Protocols", RFC 7859,
             DOI 10.17487/RFC7859, May 2016,
             <http://www.rfc-editor.org/info/rfc7859>.



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Acknowledgments

  The authors would like to thank Christopher Dearlove (BAE Systems
  ATC) who provided detailed review and valuable comments.

Authors' Addresses

  Jiazi Yi
  Ecole Polytechnique
  91128 Palaiseau Cedex
  France

  Phone: +33 1 77 57 80 85
  Email: [email protected]
  URI:   http://www.jiaziyi.com/


  Thomas Heide Clausen
  Ecole Polytechnique
  91128 Palaiseau Cedex
  France

  Phone: +33 6 6058 9349
  Email: [email protected]
  URI:   http://www.thomasclausen.org/


  Ulrich Herberg

  Email: [email protected]
  URI:   http://www.herberg.name/




















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