Security Bulletin 9122 DISA Defense Communications System

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Security Bulletin 9122 DISA Defense Communications System
23 October 1991 Published by: DDN Security Coordination Center
([email protected]) 1-(800) 365-3642

DEFENSE DATA NETWORK
SECURITY BULLETIN

The DDN SECURITY BULLETIN is distributed by the DDN SCC (Security
Coordination Center) under DISA contract as a means of communicating
information on network and host security exposures, fixes, & concerns
to security & management personnel at DDN facilities. Back issues may
be obtained via FTP (or Kermit) from NIC.DDN.MIL [192.112.36.5]
using login="anonymous" and password="guest". The bulletin pathname is
SCC:DDN-SECURITY-yynn (where "yy" is the year the bulletin is issued
and "nn" is a bulletin number, e.g. SCC:DDN-SECURITY-9122).
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! !
! The following important advisory was issued by the Computer !
! Emergency Response Team (CERT) and is being relayed unedited !
! via the Defense Information Systems Agency's Security !
! Coordination Center distribution system as a means of !
! providing DDN subscribers with useful security information. !
! !
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CA-91:20 CERT Advisory
October 22, 1991
/usr/ucb/rdist Vulnerability

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The Computer Emergency Response Team/Coordination Center (CERT/CC) has
received information concerning a vulnerability in /usr/ucb/rdist (the
location of rdist may vary depending on the operating system). This
vulnerability is present in possibly all versions of rdist. Vendors
responding with patches are listed below. Additionally, some vendors
who do not include rdist in their operating systems are identified.
Operating systems from vendors not listed in either of the two categories
below will probably be affected and the CERT/CC has proposed a workaround
for those systems.

VENDORS THAT DO NOT SHIP rdist
(Note: Even though these vendors do not ship rdist, it may have been
added later (for example, by the system administrator). It is
also possible that vendors porting one of these operating systems
may have added rdist. In both cases corrective action must be taken.)

Amdahl
AT&T System V
Data General DG/UX for AViiON Systems

VENDORS PROVIDING PATCHES

Cray Research, Inc. UNICOS 6.0/6.E/6.1 Field Alert #132 SPR 47600

For further information contact the Support Center at 1-800-950-CRAY or
612-683-5600 or e-mail [email protected].

NeXT Computer, Inc. NeXTstep Release 2.x

A new version of rdist may be obtained from your
authorized NeXT Support Center. If you are an authorized
support center, please contact NeXT through your normal
channels. NeXT also plans to make this new version of
rdist available on the public NeXT FTP archives.

Silicon Graphics IRIX 3.3.x/4.0 (fixed in 4.0.1)

Patches may be obtained via anonymous ftp from sgi.com in the
sgi/rdist directory.

Sun Microsystems, Inc. SunOS 4.0.3/4.1/4.1.1 Patch ID 100383-02

Patches may be obtained via anonymous ftp from ftp.uu.net or from local
Sun Answer Centers worldwide.

The CERT/CC is hopeful that other patches will be forthcoming. We will
be maintaining a status file, rdist-patch-status, on the cert.sei.cmu.edu
system. We will add patch availability information to this file as
it becomes known. The file is available via anonymous ftp to
cert.sei.cmu.edu and is found in pub/cert_advisories/rdist-patch-status.

All trademarks are the property of their respective holders.
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I. Description

A security vulnerability exists in /usr/ucb/rdist that
can be used to gain unauthorized privileges. Under some
circumstances /usr/ucb/rdist can be used to create setuid
root programs.

II. Impact

Any user logged into the system can gain root access.

III. Solution

A. If available, install the appropriate patch provided by
your operating system vendor.

B. If no patch is available, restrict the use of /usr/ucb/rdist
by changing the permissions on the file.

# chmod 711 /usr/ucb/rdist

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The CERT/CC wishes to thank Casper Dik of the University of Amsterdam,
The Netherlands, for bringing this vulnerability to our attention.
We would also like to thank the vendors who have responded to this problem.
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If you believe that your system has been compromised, contact CERT/CC via
telephone or e-mail.

Computer Emergency Response Team/Coordination Center (CERT/CC)
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, PA 15213-3890

Internet E-mail: [email protected]
Telephone: 412-268-7090 24-hour hotline:
CERT/CC personnel answer 7:30a.m.-6:00p.m. EST(GMT-5)/EDT(GMT-4),
on call for emergencies during other hours.

Past advisories and other computer security related information are available
for anonymous ftp from the cert.sei.cmu.edu (192.88.209.5) system.

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