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             AUSCERT External Security Bulletin Redistribution

               ESB-2005.0356 -- Sun Alert Notification 57746
        Sun TCP Connections May Experience Performance Degradation
                If Certain ICMP Error Messages Are Received
                                3 May 2005

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Solaris
Publisher:         Sun Microsystems
Operating System:  Solaris 10
                   Solaris 9
                   Solaris 8
                   Solaris 7
Impact:            Denial of Service
Access:            Remote/Unauthenticated
CVE Names:         CAN-2004-0791 CAN-2004-0790

Original Bulletin:
  http://sunsolve.sun.com/search/printfriendly.do?assetkey=1-26-57746-1

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   Sun(sm) Alert Notification 
     * Sun Alert ID: 57746
     * Synopsis: Sun TCP Connections May Experience Performance
       Degradation If Certain ICMP Error Messages Are Received
     * Category: Security
     * Product: Solaris
     * BugIDs: 5084452
     * Avoidance: None
     * State: Committed
     * Date Released: 12-Apr-2005
     * Date Closed:
     * Date Modified:

   1. Impact

   This Sun Alert describes the Sun specific impact of the issues described
   in the Internet-Draft (I-D) titled "ICMP attacks against TCP" written by
   Fernando Gont. The I-D describes how TCP(7P) connections could be reset
   and disconnected as a result of ICMP(7P) error messages. Solaris will not
   drop established TCP connections based on ICMP errors. There is a
   theoretical possibility that a TCP connection which is in the process of
   being set up could be terminated before being established. However, there
   is no risk of data corruption or compromise in this scenario.

   The draft also describes ICMP messages which could impact the performance
   of existing TCP connections. This issue affects all current versions of
   Solaris and thus Sun plans on improving how ICMP errors are handled to
   further mitigate the impact of such ICMP messages.

   This issue is also described in the following documents:

   IETF Internet Draft at
   [1]http://www.ietf.org/internet-drafts/draft-gont-tcpm-icmp-attacks-03.txt

   CERT Vulnerability Note VU#222750 at
   [2]http://www.kb.cert.org/vuls/222750

   CVEs CAN-2004-0790 at
   [3]http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0790

   CVEs CAN-2004-0791 at
   [4]http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0791

   2. Contributing Factors

   This issue can occur in the following releases:

   SPARC Platform

     * Solaris 7
     * Solaris 8
     * Solaris 9
     * Solaris 10

   x86 Platform

     * Solaris 7
     * Solaris 8
     * Solaris 9
     * Solaris 10

   3. Symptoms

   In order to verify if ICMP error messages are being sent to a specific
   system on the network, a network monitoring tool such as snoop(1M) can be
   used from either the specific system or another system on the same network.

   The following command can be run (as "root"):

    # snoop -o <output-file>


   Afterwards, the snoop(1M) utility can display the packets captured in
   the "output-file" using the "-v" and "-i" options, as in:

    # snoop -v -i output-file icmp icmp6


   and inspect the output for ICMP packets which will look similar to the
   following:

    ICMP:  ----- ICMP Header -----
    ICMP:
    ICMP:  Type = 0 (Echo reply)
    ICMP:  Code = 0 (ID: 5417 Sequence number: 0)
    ICMP:  Checksum = be96
    ICMP:

   If the "Type" value and the "Code" value (for multiple packets) are
   equal to any of the following combinations:

    Type    Code    Name
    ----    ----    -----------------
     4       0      Source Quench
     3       *      Net/Host/Protocol/Port Unreachable, etc.
     5       *      Redirect
     6       0      Alternate Host Address
     11      *      Time Exceeded
     12      *      Parameter Problem


   then the system may be the target of the described ICMP issue.

   Solution Summary

   4. Relief/Workaround

   There is no workaround for this issue at this time.

   5. Resolution

   A final resolution is pending completion.


   This Sun Alert notification is being provided to you on an "AS IS"
   basis. This Sun Alert notification may contain information provided by
   third parties. The issues described in this Sun Alert notification may
   or may not impact your system(s). Sun makes no representations,
   warranties, or guarantees as to the information contained herein. ANY
   AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
   WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
   NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT
   YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT,
   INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE
   OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN.
   This Sun Alert notification contains Sun proprietary and confidential
   information. It is being provided to you pursuant to the provisions of
   your agreement to purchase services from Sun, or, if you do not have
   such an agreement, the Sun.com Terms of Use. This Sun Alert
   notification may only be used for the purposes contemplated by these
   agreements.

   Copyright 2000-2005 Sun Microsystems, Inc., 4150 Network Circle, Santa
   Clara, CA 95054 U.S.A. All rights reserved.


References

   1. http://www.ietf.org/internet-drafts/draft-gont-tcpm-icmp-attacks-03.txt
   2. http://www.kb.cert.org/vuls/222750
   3. http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0790
   4. http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0791

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