[cisco-ttl] FW: Cisco Security Advisory: Cisco IOS Malformed BGP packet causes reload

From: Levent Ogut (levent_at_networkakademi.com)
Date: Wed Jun 16 2004 - 12:42:55 GMT

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    -----Original Message-----
    From: owner-nanog_at_merit.edu [mailto:owner-nanog_at_merit.edu] On Behalf Of
    Cisco Systems Product Security Incident Response Team
    Sent: Wednesday, June 16, 2004 6:00 PM
    To: nanog_at_merit.edu
    Cc: psirt_at_cisco.com
    Subject: Cisco Security Advisory: Cisco IOS Malformed BGP packet causes
    reload

    -----BEGIN PGP SIGNED MESSAGE-----
    Hash: SHA1

    Cisco Security Advisory: Cisco IOS Malformed BGP Packet Causes Reload

    Revision 1.0
    ============

    Last Updated June 16 15:00 UTC (GMT)

    For Public Release 2004 June 16 15:00 UTC (GMT)

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    ---
    Please provide your feedback on this document.
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    Contents
        Summary
        Affected Products
        Details
        Impact
        Software Versions and Fixes
        Obtaining Fixed Software
        Workarounds
        Exploitation and Public Announcements
        Status of This Notice: FINAL
        Distribution
        Revision History
        Cisco Security Procedures
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    ---
    Summary
    =======
    A Cisco device running IOS and enabled for the Border Gateway Protocol (BGP)
    is vulnerable to a Denial of Service (DOS) attack from a malformed BGP
    packet. The BGP protocol is not enabled by default, and must be configured
    in order to accept traffic from an explicitly defined peer. Unless the
    malicious traffic appears to be sourced from a configured, trusted peer, it
    would be difficult to inject a malformed packet.
    Cisco has made free software available to address this problem.
    This advisory is available at
    http://www.cisco.com/warp/public/707/cisco-sa-20040616-bgp.shtml.
    Affected Products
    =================
    Vulnerable Products
    This issue affects all Cisco devices running any unfixed version of Cisco
    IOS code and configured for BGP routing.
    A router which is running the BGP process will have a line in the config
    defining the AS number, which can be seen by issuing the command show
    running-config:
        router bgp <AS number>
    This vulnerability is present in any unfixed version of IOS, from the
    beginning of support for the BGP protocol, including versions 9.x, 10.x,
    11.x and 12.x.
    To determine the software running on a Cisco product, log in to the device
    and issue the show version command to display the system banner. Cisco IOS
    software will identify itself as "Internetwork Operating System Software" or
    simply "IOS R." On the next line of output, the image name will be displayed
    between parentheses, followed by "Version" and the IOS release name. Other
    Cisco devices will not have the show version command or will give different
    output.
    The following example identifies a Cisco product running IOS release 12.0(3)
    with an installed image name of C2500-IS-L:
        Cisco Internetwork Operating System Software IOS (TM)
        
        2500 Software (C2500-IS-L), Version 12.0(3), RELEASE SOFTWARE
    The release train label is "12.0."
    The next example shows a product running IOS release 12.0(2a)T1 with an
    image name of C2600-JS-MZ:
        Cisco Internetwork Operating System Software IOS (tm)
        C2600 Software (C2600-JS-MZ), Version 12.0(2a)T1, RELEASE SOFTWARE (fc1)
    Additional information about Cisco IOS release naming can be found at
    http://www.cisco.com/warp/public/620/1.html.
    Products Confirmed Not Vulnerable
    Products confirmed not to be vulnerable include devices which cannot
    participate in BGP or cannot be configured for BGP.
    Details
    =======
    The Border Gateway Protocol (BGP) is a routing protocol defined by RFC 1771,
    and designed to manage IP routing in large networks. An affected Cisco
    device running a vulnerable version of Cisco IOS software and enabling the
    BGP protocol will reload when a malformed BGP packet is received. BGP runs
    over TCP, a reliable transport protocol which requires a valid three way
    handshake before any further messages will be accepted. The Cisco IOS
    implementation of BGP requires the explicit definition of a neighbor before
    a connection can be established, and traffic must appear to come from that
    neighbor. These implementation details make it very difficult to send a BGP
    packet to a Cisco IOS device from an unauthorized source.
    A Cisco device receiving an invalid BGP packet will reset and may take
    several minutes to become fully functional. This vulnerability may be
    exploited repeatedly resulting in an extended DOS attack. This issue is
    documented in bug IDs CSCdu53656 and CSCea28131.
    Impact
    ======
    Successful exploitation of this vulnerability results in a reload of the
    device. Repeated exploitation could result in a sustained DoS attack.
    Software Versions and Fixes
    ===========================
    Note: Many of the releases in this table were fixed prior to the release of
    other IOS advisories. Read the table carefully to determine if your IOS
    release contains these fixes. Most fixed releases for the TCP and SNMP
    advisories such as
    http://www.cisco.com/warp/public/707/cisco-sa-20040420-snmp.shtml and
    http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml
    contained the fixes for this BGP advisory.
    Each row of the Cisco IOS software table (below) describes a release train
    and the platforms or products for which it is intended. If a given release
    train is vulnerable, then the earliest possible releases that contain the
    fix (the "First Fixed Release") and the anticipated date of availability for
    each are listed in the "Rebuild," "Interim," and "Maintenance" columns. A
    device running a release in the given train that is earlier than the release
    in a specific column (less than the First Fixed Release) is known to be
    vulnerable. The release should be upgraded at least to the indicated release
    or a later version (greater than or equal to the First Fixed Release label).
    When selecting a release, keep in mind the following definitions:
    Maintenance
    Most heavily tested, stable, and highly recommended release of a release
    train in any given row of the table.
    Rebuild
    Constructed from the previous maintenance or major release in the same
    train, it contains the fix for a specific defect. Although it receives less
    testing, it contains only the minimal changes necessary to repair the
    vulnerability.
    Interim
    Built at regular intervals between maintenance releases and receives less
    testing. Interims should be selected only if there is no other suitable
    release that addresses the vulnerability. Interim images should be upgraded
    to the next available maintenance release as soon as possible. Interim
    releases are not available through manufacturing, and usually they are not
    available for customer download from Cisco.com without prior arrangement
    with the Cisco TAC.
    In all cases, customers should exercise caution to confirm that the devices
    to be upgraded contain sufficient memory and that current hardware and
    software configurations will continue to be supported properly by the new
    software release. If the information is not clear, contact the Cisco TAC for
    assistance as shown in the Obtaining Fixed Software section below.
    More information on Cisco IOS software release names and abbreviations is
    available at http://www.cisco.com/warp/public/620/1.html.
    The fixes will be available at the Software Center located at
    http://www.cisco.com/tacpage/sw-center/.
    For software installation and upgrade procedures, see
    http://www.cisco.com/warp/public/130/upgrade_index.shtml.
    For a current view of all posted and repaired images for Cisco IOS, please
    check the listing available to registered Cisco.com users at: 
    http://www.cisco.com/tacpage/sw-center/sw-ios.shtml.
    +------------------------------------------------+
    |   Major    | Availability of Repaired Releases |
    |  Release   |                 *                 |
    |------------+-----------------------------------|
    | Affected   |           | Interim |             |
    | 11.1-Based | Rebuild   | **      | Maintenance |
    | Release    |           |         |             |
    |------------+-----------------------------------|
    | 11.1       | Migrate to 11.2 or later          |
    |------------+-----------------------------------|
    | 11.1AA     | Migrate to 11.2P or later         |
    |------------+-----------------------------------|
    | 11.1CA     | Migrate to 12.0 or later          |
    |------------+-----------------------------------|
    | 11.1CC     | Migrate to 12.0 or later          |
    |------------+-----------------------------------|
    | Affected   |           | Interim |             |
    | 11.2-Based | Rebuild   | **      | Maintenance |
    | Release    |           |         |             |
    |------------+-----------+---------+-------------|
    | 11.2       | 11.2(26g) |         |             |
    |------------+-----------+---------+-------------|
    | 11.2P      | 11.2(26)  |         |             |
    |            | P7        |         |             |
    |------------+-----------------------------------|
    | 11.2SA     | Not Vulnerable                    |
    |------------+-----------------------------------|
    | Affected   |           | Interim |             |
    | 11.3-Based | Rebuild   | **      | Maintenance |
    | Release    |           |         |             |
    |------------+-----------+---------+-------------|
    | 11.3       | 11.3(11f) |         |             |
    |------------+-----------+---------+-------------|
    | 11.3T      | 11.3(11b) |         |             |
    |            | T5        |         |             |
    |------------+-----------+---------+-------------|
    | Affected   |           | Interim |             |
    | 12.0-Based | Rebuild   | **      | Maintenance |
    | Release    |           |         |             |
    |------------+-----------+---------+-------------|
    | 12.0       |           |         | 12.0(27)    |
    |------------+-----------------------------------|
    | 12.0DA     | Migrate to 12.2DA or later        |
    |------------+-----------------------------------|
    |            | 12.0(21)  |         |             |
    |            | S7        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(22)  |         |             |
    |            | S2e       |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(22)  |         |             |
    |            | S3c       |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(22)  |         |             |
    |            | S4a       |         |             |
    |            |-----------+---------+-------------|
    | 12.0S      | 12.0(22)  |         |             |
    |            | S5        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(23)  |         |             |
    |            | S3        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(24)  |         |             |
    |            | S2        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(25)  |         |             |
    |            | S1        |         |             |
    |            |-----------+---------+-------------|
    |            |           |         | 12.0(26)S   |
    |------------+-----------------------------------|
    | 12.0SL     | Migrate to 12.0(23)S3 or later    |
    |------------+-----------------------------------|
    |            | 12.0(17)  |         |             |
    |            | ST10      |         |             |
    |            | Available |         |             |
    |            | upon      |         |             |
    | 12.0ST     | request   |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(21)  |         |             |
    |            | ST7       |         |             |
    |            |-----------------------------------|
    |            | Migrate to 12.0(26)S2 or later    |
    |------------+-----------------------------------|
    | 12.0SV     |           |         | 12.0(27)SV  |
    |------------+-----------+---------+-------------|
    | 12.0SX     | 12.0(25)  |         |             |
    |            | SX        |         |             |
    |------------+-----------+---------+-------------|
    |            | 12.0(23)  |         |             |
    |            | SZ3       |         |             |
    |12.0SZ      |-----------+---------+-------------|
    |            |           |         | 12.0(26)SZ  |
    |            |-----------------------------------|
    |            | Migrate to 12.0(26)S2 or later    |
    |------------+-----------------------------------|
    | 12.0T      | Migrate to 12.1 or later          |
    |------------+-----------------------------------|
    |            | 12.0(16)  |         |             |
    |            | W5(21c)   |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(25)  |         |             |
    |            | W5(27b)   |         |             |
    |12.0W5      |-----------+---------+-------------|
    |            | 12.0(26)  |         |             |
    |            | W5(28a)   |         |             |
    |            |-----------+---------+-------------|
    |            | 12.0(27)  |         |             |
    |            | W5(29)    |         |             |
    |------------+-----------------------------------|
    | 12.0WC     | Not Vulnerable                    |
    |------------+-----------------------------------|
    | 12.0WX     | Migrate to 12.0W5 or later        |
    |------------+-----------------------------------|
    | 12.0XA     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XC     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XD     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XE     | Migrate to 12.1E latest or later  |
    |------------+-----------------------------------|
    | 12.0XG     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XH     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XI     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XJ     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XK     | Migrate to 12.1T latest or later  |
    |------------+-----------------------------------|
    | 12.0XL     | Migrate to 12.2 latest or later   |
    |------------+-----------------------------------|
    | 12.0XN     | Migrate to 12.1 latest or later   |
    |------------+-----------------------------------|
    | 12.0XP     | Not Vulnerable                    |
    |------------+-----------------------------------|
    | 12.0XR     | Migrate to 12.2 latest or later   |
    |------------+-----------------------------------|
    | 12.0XS     | Migrate to 12.1E latest or later  |
    |------------+-----------------------------------|
    | 12.0XU     | Not Vulnerable                    |
    |------------+-----------------------------------|
    | Affected   |           | Interim |             |
    | 12.1-Based | Rebuild   | **      | Maintenance |
    | Release    |           |         |             |
    |------------+-----------+---------+-------------|
    | 12.1       |           |         | 12.1(20)    |
    |------------+-----------------------------------|
    | 12.1AA     | Migrate to 12.2 latest or later   |
    |------------+-----------------------------------|
    |            | Not Vulnerable                    |
    |12.1AX      |-----------------------------------|
    |            | 12.1AY    | Not Vulnerable        |
    |------------+-----------+-----------------------|
    | 12.1AZ     |           |         | 12.1(14)AZ  |
    |------------+-----------------------------------|
    | 12.1DA     | Migrate to 12.2DA or later        |
    |------------+-----------------------------------|
    | 12.1DB     | Migrate to 12.2B or later         |
    |------------+-----------------------------------|
    |            | 12.1(6)   |         |             |
    |            | E12.0     |         |             |
    |            |-----------+---------+-------------|
    |            | 12.1(8b)  |         |             |
    |            | E14       |         |             |
    |            |-----------+---------+-------------|
    |            | 12.1(11b) |         |             |
    |            | E12.0     |         |             |
    |            |-----------+---------+-------------|
    |            | 12.1(12c) |         |             |
    | 12.1E      | E7        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.1(13)  |         |             |
    |            | E6        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.1(14)  |         |             |
    |            | E4        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.1(19)E |         |             |
    |            |-----------+---------+-------------|
    |            |           |         | 12.1(20)E   |
    |------------+-----------+---------+-------------|
    | 12.1EA     | 12.1(14)  |         |             |
    |            | EA1       |         |             |
    |------------+-----------+---------+-------------|
    | 12.1EB     | 12.1(14)  |         |             |
    |            | EB1       |         |             |
    |------------+-----------+---------+-------------|
    | 12.1EC     |           |         | 12.1(19)EC  |
    |------------+-----------+---------+-------------|
    | 12.1EO     |           |         | 12.1(19)EO  |
    |------------+-----------+---------+-------------|
    | 12.1EV     | 12.1(12c) |         |             |
    |            | EV2       |         |             |
    |------------+-----------+---------+-------------|
    | 12.1EW     |           |         | 12.1(19)EW  |
    |------------+-----------------------------------|
    | 12.1EX     | Migrate to 12.1(14)E4 or later    |
    |------------+-----------------------------------|
    | 12.1EY     | Migrate to 12.1(14)E4 or later    |
    |------------+-----------------------------------|
    | 12.1T      | 12.1(5)   |         |             |
    |            | T19       |         |             |
    |------------+-----------------------------------|
    | 12.1XA     | Migrate to 12.1(5)T19 or later    |
    |------------+-----------------------------------|
    | 12.1XB     | Migrate to 12.1(5)T19 or later    |
    |------------+-----------------------------------|
    | 12.1XC     | Migrate to 12.1(5)T19 or later    |
    |------------+-----------------------------------|
    | 12.1XD     | Migrate to 12.2 or later          |
    |------------+-----------------------------------|
    | 12.1XE     | Migrate to 12.1E latest or later  |
    |------------+-----------------------------------|
    | 12.1XF     | Migrate to 12.2(4)T6 or later     |
    |------------+-----------------------------------|
    | 12.1XG     | Migrate to 12.2(4)T6 or later     |
    |------------+-----------------------------------|
    | 12.1XH     | Migrate to 12.2 or later          |
    |------------+-----------------------------------|
    | 12.1XI     | Migrate to 12.2 latest or later   |
    |------------+-----------------------------------|
    | 12.1XJ     | Migrate to 12.2(4)T6 or later     |
    |------------+-----------------------------------|
    | 12.1XL     | Migrate to 12.2T latest or later  |
    |------------+-----------------------------------|
    | 12.1XM     | Migrate to 12.2T latest or later  |
    |------------+-----------------------------------|
    | 12.1XP     | Migrate to 12.2(4)T6 or later     |
    |------------+-----------------------------------|
    | 12.1XQ     | Migrate to 12.2T latest or later  |
    |------------+-----------------------------------|
    | 12.1XR     | Migrate to 12.2T latest or later  |
    |------------+-----------------------------------|
    | 12.1XT     | Migrate to 12.2(4)T6 or later     |
    |------------+-----------------------------------|
    | 12.1XU     | Migrate to 12.2T latest or later  |
    |------------+-----------------------------------|
    | 12.1XV     | Migrate to 12.2XB or later        |
    |------------+-----------------------------------|
    | 12.1XY     | Migrate to 12.2XB or later        |
    |------------+-----------------------------------|
    | 12.1YA     | Migrate to 12.2(8)T10 or later    |
    |------------+-----------------------------------|
    | 12.1YB     | Migrate to 12.2(4)T6 or later     |
    |------------+-----------------------------------|
    | 12.1YC     | Migrate to 12.2(8)T10 or later    |
    |------------+-----------------------------------|
    | 12.1YD     | Migrate to 12.2(8)T10 or later    |
    |------------+-----------------------------------|
    | 12.1YH     | Migrate to 12.2(13)T5 or later    |
    |------------+-----------------------------------|
    | 12.1YJ     | Not Vulnerable                    |
    |------------+-----------------------------------|
    | Affected   |           | Interim |             |
    | 12.2-Based | Rebuild   | **      | Maintenance |
    | Release    |           |         |             |
    |------------+-----------+---------+-------------|
    |            | 12.2(10d) |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(12e) |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(12h) |         |             |
    | 12.2       | M1        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(13c) |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(16a) |         |             |
    |            |-----------+---------+-------------|
    |            |           |         | 12.2(17)    |
    |------------+-----------+---------+-------------|
    | 12.2B      | 12.2(15)  |         |             |
    |            | B1        |         |             |
    |------------+-----------+---------+-------------|
    | 12.2BC     | 12.2(15)  |         |             |
    |            | BC1       |         |             |
    |------------+-----------------------------------|
    | 12.2BW     | Migrate to 12.2(15)T12 or later   |
    |------------+-----------------------------------|
    | 12.2BX     |           |         | 12.2(16)BX  |
    |------------+-----------------------------------|
    | 12.2BY     | Migrate to 12.2(15)B1 or later    |
    |------------+-----------------------------------|
    | 12.2BZ     | Migrate to 12.2(16)BX or later    |
    |------------+-----------------------------------|
    | 12.2CX     |           |         | 12.2(15)CX  |
    |------------+-----------+---------+-------------|
    | 12.2DA     | 12.2(12)  |         |             |
    |            | DA6       |         |             |
    |------------+-----------------------------------|
    | 12.2DD     | Migrate to 12.2(15)B1 or later    |
    |------------+-----------------------------------|
    | 12.2DX     | Migrate to 12.2(15)B1 or later    |
    |------------+-----------------------------------|
    | 12.2EW     |           |         | 12.2(18)EW  |
    |------------+-----------+---------+-------------|
    | 12.2JA     |           |         | 12.2(13)JA  |
    |------------+-----------+---------+-------------|
    |            | 12.2(14)  |         |             |
    | 12.2S      | S2        |         |             |
    |            |-----------+---------+-------------|
    |            |           |         | 12.2(18)S   |
    |------------+-----------+---------+-------------|
    | 12.2SE     |           |         | 12.2(18)SE  |
    |------------+-----------+---------+-------------|
    | 12.2SU     |           |         | 12.2(14)SU  |
    |------------+-----------+---------+-------------|
    | 12.2SV     |           |         | 12.2(18)SV  |
    |------------+-----------+---------+-------------|
    | 12.2SW     |           |         | 12.2(18)SW  |
    |------------+-----------+---------+-------------|
    | 12.2SX     | 12.2(14)  |         |             |
    |            | SX2       |         |             |
    |------------+-----------+---------+-------------|
    | 12.2SXA    | 12.2(17b) |         |             |
    |            | SXA       |         |             |
    |------------+-----------+---------+-------------|
    | 12.2SXB    | 12.2(17d) |         |             |
    |            | SXB       |         |             |
    |------------+-----------+---------+-------------|
    | 12.2SY     |           |         | 12.2(14)SY  |
    |------------+-----------+---------+-------------|
    | 12.2SZ     | 12.2(14)  |         |             |
    |            | SZ2       |         |             |
    |------------+-----------+---------+-------------|
    |            | 12.2(4)T6 |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(8)   |         |             |
    |            | T10       |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(11)  |         |             |
    | 12.2T      | T9        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(13)  |         |             |
    |            | T5        |         |             |
    |            |-----------+---------+-------------|
    |            | 12.2(15)  |         |             |
    |            | T4        |         |             |
    |------------+-----------------------------------|
    | 12.2XA     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XB     | 12.2(2)   |         |             |
    |            | XB16      |         |             |
    |------------+-----------------------------------|
    | 12.2XD     | Migrate to 12.2(8)T10 or later    |
    |------------+-----------------------------------|
    | 12.2XE     | Migrate to 12.2(8)T10 or later    |
    |------------+-----------------------------------|
    | 12.2XG     | Migrate to 12.2(8)T10 or later    |
    |------------+-----------------------------------|
    | 12.2XH     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XI     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XJ     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XK     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XL     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2XM     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2XN     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XQ     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XS     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XT     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2XU     | Migrate to 12.2(15)T12 or later   |
    |------------+-----------------------------------|
    | 12.2XW     | Migrate to 12.2(11)T9 or later    |
    |------------+-----------------------------------|
    | 12.2YA     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2YB     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2YC     | Migrate to 12.2(11)T11 or later   |
    |------------+-----------------------------------|
    | 12.2YD     | Migrate to 12.2(8)YY or later     |
    |------------+-----------------------------------|
    | 12.2YE     | Migrate to 12.2S or later         |
    |------------+-----------------------------------|
    | 12.2YF     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2YG     | Migrate to 12.2(13)T5 or later    |
    |------------+-----------------------------------|
    | 12.2YH     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2YJ     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2YL     | Migrate to 12.3(2)T or later      |
    |------------+-----------------------------------|
    | 12.2YM     | Migrate to 12.3(2)T or later      |
    |------------+-----------------------------------|
    | 12.2YN     | Migrate to 12.3(2)T or later      |
    |------------+-----------------------------------|
    | 12.2YO     | Migrate to 12.2(14)SY or later    |
    |------------+-----------------------------------|
    | 12.2YP     | 12.2(11)  |         |             |
    |            | YP1       |         |             |
    |------------+-----------------------------------|
    | 12.2YQ     | Migrate to 12.3(4)T or later      |
    |------------+-----------------------------------|
    | 12.2YR     | Migrate to 12.3(4)T or later      |
    |------------+-----------------------------------|
    | 12.2YS     | Migrate to 12.3T or later         |
    |------------+-----------------------------------|
    | 12.2YT     | Migrate to 12.2(15)T4 or later    |
    |------------+-----------------------------------|
    | 12.2YU     | Migrate to 12.3(4)T or later      |
    |------------+-----------------------------------|
    | 12.2YV     | Migrate to 12.3(4)T or later      |
    |------------+-----------------------------------|
    | 12.2YW     | Migrate to 12.3(2)T or later      |
    |------------+-----------------------------------|
    | 12.2YX     | Migrate to 12.2(14)SU or later    |
    |------------+-----------------------------------|
    | 12.2YY     | 12.2(8)   |         |             |
    |            | YY3       |         |             |
    |------------+-----------------------------------|
    | 12.2YZ     | Migrate to 12.2(14)SZ or later    |
    |------------+-----------------------------------|
    | 12.2ZA     | 12.2(14)  |         |             |
    |            | ZA2       |         |             |
    |------------+-----------------------------------|
    | 12.2ZB     | Migrate to 12.3T or later         |
    |------------+-----------------------------------|
    | 12.2ZC     | Migrate to 12.3T or later         |
    |------------+-----------------------------------|
    | 12.2ZE     | Migrate to 12.3 or later          |
    |------------+-----------------------------------|
    | 12.2ZF     | Migrate to 12.3(4)T or later      |
    |------------+-----------------------------------|
    | 12.2ZG     | Migrate to 12.3(4)T or later      |
    |------------+-----------------------------------|
    | 12.2ZH     | Migrate to 12.3(4)T or later      |
    |------------+-----------------------------------|
    | 12.2ZI     | Migrate to 12.2(18)S or later     |
    |------------+-----------------------------------|
    | 12.2ZK     |           |         | 12.2(15)ZK  |
    |------------+-----------+---------+-------------|
    | 12.2ZL     |           |         | 12.2(15)ZL  |
    |------------+-----------------------------------|
    | 12.2ZN     | Migrate to 12.3(2)T or later      |
    |------------+-----------------------------------|
    | 12.2ZO     |           |         | 12.2(15)ZO  |
    |------------+-----------+---------+-------------|
    | 12.2ZP     |           |         | 12.2(13)ZP  |
    |------------+-----------+---------+-------------|
    | Affected   |           | Interim |             |
    | 12.3-Based | Rebuild   | **      | Maintenance |
    | Release    |           |         |             |
    |------------+-----------------------------------|
    | 12.3       | Not Vulnerable                    |
    |------------+-----------------------------------|
    | 12.3T      | Not Vulnerable                    |
    +------------------------------------------------+
    Obtaining Fixed Software
    ========================
    Customers with Service Contracts
    Customers with contracts should obtain upgraded software through their
    regular update channels. For most customers, this means that upgrades should
    be obtained through the Software Center on Cisco's worldwide website at
    http://www.cisco.com/tacpage/sw-center.
    Customers using Third-party Support Organizations
    Customers whose Cisco products are provided or maintained through prior or
    existing agreement with third-party support organizations such as Cisco
    Partners, authorized resellers, or service providers should contact that
    support organization for assistance with the upgrade, which should be free
    of charge.
    Customers without Service Contracts
    Customers who purchase direct from Cisco but who do not hold a Cisco service
    contract and customers who purchase through third-party vendors but are
    unsuccessful at obtaining fixed software through their point of sale should
    get their upgrades by contacting the Cisco Technical Assistance Center
    (TAC). TAC contacts are as follows.
      * +1 800 553 2447 (toll free from within North America)
      * +1 408 526 7209 (toll call from anywhere in the world)
      * e-mail: tac_at_cisco.com
    Please have your product serial number available and give the URL of this
    notice as evidence of your entitlement to a free upgrade. Free upgrades for
    non-contract customers must be requested through the TAC.
    Please do not contact either "psirt_at_cisco.com" or "security-alert_at_cisco.com"
    for software upgrades.
    See http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for
    additional TAC contact information, including special localized telephone
    numbers and instructions and e-mail addresses for use in various languages.
    Customers may only install and expect support for the feature sets they have
    purchased. By installing, downloading, accessing or otherwise using such
    software upgrades, customers agree to be bound by the terms of Cisco's
    software license terms found at
    http://www.cisco.com/public/sw-license-agreement.html,
    or as otherwise set forth at Cisco.com Downloads at
    http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
    Workarounds
    ===========
    The effectiveness of any workaround is dependent on specific customer
    situations such as product mix, network topology, traffic behavior, and
    organizational mission. Due to the variety of affected products and
    releases, customers should consult with their service provider or support
    organization to ensure any applied workaround is the most appropriate for
    use in the intended network before it is deployed.
    For additional information regarding BGP security risk assessment,
    mitigation techniques, and deployment best practices, please consult ftp://
    ftp-eng.cisco.com/cons/isp/security/BGP-Risk-Assesment-v.pdf.
    BGP MD5
    Under normal circumstances, due to inherent security factors in the TCP
    protocol such as sequence number checks, it is difficult but possible to
    forge an appropriate packet to exploit this problem. Configuring your Cisco
    IOS device for BGP MD5 authentication is a valid workaround to protect the
    vulnerable device.
    This can be configured as shown in the following example:
        router(config)# router bgp 
         router(config-router)# neighbor <IP_address> password
    <enter_your_secret_here>
    It is necessary to configure the same shared MD5 secret on both peers and at
    the same time. Failure to do so will break the existing BGP session and the
    new session will not get established until the exact same secret is
    configured on both devices. For a detailed discussion on how to configure
    BGP, refer to the following document:
    http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_configuratio
    n_guide_chapter09186a00800ca571.html
    Once the secret is configured, it is prudent to change it periodically. The
    exact period must fit within your company security policy but it should not
    be longer than a few months. When changing the secret, again it must be done
    at the same time on both devices. Failure to do so will break your existing
    BGP session. The exception is if your Cisco IOS software release contains
    the integrated CSCdx23494 fix on both sides of the connection. With this
    fix, the BGP session will not be terminated when the MD5 secret is changed
    only on one side. The BGP updates, however, will not be processed until
    either the same secret is configured on both devices or the secret is
    removed from both devices.
    Infrastructure Access Control Lists
    Although it is often difficult to block traffic transiting your network, it
    is possible to identify traffic which should never be allowed to target your
    infrastructure devices and block that traffic at the border of your network.
    Infrastructure ACLs are considered a network security best practice and
    should be considered as a long-term addition to good network security as
    well as a workaround for this specific vulnerability. The white paper
    entitled "Protecting Your Core: Infrastructure Protection Access Control
    Lists" presents guidelines and recommended deployment techniques for
    infrastructure protection
    ACLs:
    http://www.cisco.com/warp/public/707/iacl.html
    Exploitation and Public Announcements
    =====================================
    The research which led to this vulnerability being discovered was announced
    in a public announcement at NANOG in June 2003. The Cisco PSIRT team is not
    aware of any malicious use of the vulnerabilities described in this
    advisory. We were made aware of this issue through internal testing as well
    as notification from a research team at the University of California at
    Santa Barbara.
    The Cisco PSIRT is not aware of any malicious use of the vulnerability
    described in this advisory.
    Status of This Notice: FINAL
    =====================
    This Advisory is provided on an "as is" basis and does not imply any kind of
    guarantee or warranty of any kind. Your use of the information on the
    Advisory or materials linked from the Advisory is at your own risk. Cisco
    reserves the right to change or update this notice at anytime.
    Distribution
    ============
    This advisory will be posted on Cisco's worldwide website at
    http://www.cisco.com/warp/public/707/cisco-sa-20040616-bgp.shtml.
    In addition to worldwide web posting, a text version of this notice is
    clear-signed with the Cisco PSIRT PGP key and is posted to the following
    e-mail and Usenet news recipients.
      * cust-security-announce_at_cisco.com
      * first-teams_at_first.org (includes CERT/CC)
      * bugtraq_at_securityfocus.com
      * vulnwatch_at_wulnwatch.org
      * cisco_at_spot.colorado.edu
      * cisco-nsp_at_puck.nether.net
      * full-disclosure_at_lists.netsys.com
      * comp.dcom.sys.cisco_at_newsgate.cisco.com
    Future updates of this advisory, if any, will be placed on Cisco's worldwide
    website, but may or may not be actively announced on mailing lists or
    newsgroups. Users concerned about this problem are encouraged to check the
    above URL for any updates.
    Revision History
    ================
    +---------------------------------------------+
    | Revision  | 16-June-2004 | Initial Public   |
    | 1.0       |              | Release          |
    +---------------------------------------------+
    Cisco Security Procedures
    =========================
    Complete information on reporting security vulnerabilities in Cisco
    products, obtaining assistance with security incidents, and registering to
    receive security information from Cisco, is available on Cisco's worldwide
    website at http://www.cisco.com/warp/public/707/sec_incident_response.shtml.
    This includes instructions for press inquiries regarding Cisco security
    notices. All Cisco security advisories are available at
    http://www.cisco.com/go/psirt.
    -
    ----------------------------------------------------------------------------
    ---
    All contents are Copyright C 1992-2004 Cisco Systems, Inc. All rights
    reserved.
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    This archive was generated by hypermail 2.1.5 : Wed Jun 16 2004 - 16:49:42 GMT