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Cisco Security Advisory: Cisco IOS Software Processing of SAA Packets


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Date: Thu, 15 May 2003 19:04:43 +0100 (BST)
From: Cisco Systems Product Security Incident Response Team <psirt@cisco.com.>
To: [email protected]
Subject: Cisco Security Advisory: Cisco IOS Software Processing of SAA Packets


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Cisco Security Advisory: Cisco IOS Software Processing of SAA Packets

Revision 1.0

For Public Release 2003 May 15 15:00 UTC (GMT)

- --------------------------------------------------------------------------


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


- --------------------------------------------------------------------------


Summary
=======
The Service Assurance Agent (SAA) is the new name for the Response Time
Reporter (RTR) feature.

The router is vulnerable only if the RTR responder is enabled. When the
router receives a malformed RTR packet, it will crash. RTR is disabled by
default. Although RTR was introduced in Cisco IOS╝ Software Release 11.2,
only the following main releases are vulnerable:

  * 12.0S, SC, ST, SL, SP, SX
   
   
  * 12.1, E, EA, EC, EX, EY
   
   
  * 12.2, DA, S
   
   
For the complete list please see the Software Versions and Fixes section.

No other Cisco product is vulnerable.

There is no workaround short of disabling the RTR responder. It is
possible to mitigate the vulnerability by applying the access control
list (ACL) on the router.

This advisory is available at http://www.cisco.com/warp/public/707/
cisco-sa-20030515-saa.shtml.

Affected Products
=================
This vulnerability affects the following main Cisco IOS Software releases
(some X releases are also affected, and those details are in the Software
Version and Fixes section).

+-----------------------------------------+
|  Major  |      Vulnerable Releases      |
| Release |                               |
|---------+-------------------------------|
| 12.0S   | 15, 16, 17, 18, 19, 21        |
|---------+-------------------------------|
| 12.0SC  | 15, 16                        |
|---------+-------------------------------|
| 12.0SL  | 15, 17, 19                    |
|---------+-------------------------------|
| 12.0ST  | 16, 17, 18, 19, 20, 21        |
|---------+-------------------------------|
| 12.0SP  | 19, 20                        |
|---------+-------------------------------|
| 12.0SX  | 21                            |
|---------+-------------------------------|
| 12.1    | 10, 10a, 11, 11a, 11b, 12,    |
|         | 12a, 12b, 12c, 13, 14, 14.5   |
|---------+-------------------------------|
| 12.1E   | 10, 11b, 11.5                 |
|---------+-------------------------------|
| 12.1EA  | 8, 9                          |
|---------+-------------------------------|
| 12.1EC  | 10, 10.5                      |
|---------+-------------------------------|
| 12.1EX  | 10                            |
|---------+-------------------------------|
| 12.1EY  | 10                            |
|---------+-------------------------------|
| 12.2    | 6.8a, 7, 7a, 7b, 7c           |
|---------+-------------------------------|
| 12.2DA  | 7, 9.4                        |
|---------+-------------------------------|
| 12.2S   | 9, 10.5                       |
+-----------------------------------------+

No other Cisco products are affected.

Details
=======
The RTR feature allows you to monitor network performance, network
resources, and applications by measuring response times and availability.
With this feature you can perform troubleshooting, problem notifications,
and problem analysis based on response time reporter statistics.

A router is vulnerable only if the RTR responder is enabled. In order to
verify this, check the router's configuration. Execute the following
command while logged on a router:

    Router>show rtr responder
         RTR Responder is: Enabled
         Number of control messages received: 0 Number of errors: 0 
         Recent sources:
         Recent error sources:


If you notice the line "RTR Responder is: Enabled," then you are
vulnerable.

Alternatively, you can use this procedure:

    Router>show ip socket
         show ip socket
         Proto    Remote      Port      Local       Port  In Out Stat TTY
OutputIF
         ....
          17 0.0.0.0             0 10.0.0.1         1967   0   0   89   0


If you notice a line as in the example above where the router is
listening to the port 1967, then you are vulnerable.

For Cisco IOS Software, this vulnerability is documented as two Cisco Bug
IDs: CSCdx17916 and CSCdx61997.

Impact
======
By sending malformed RTR packets, it is possible to crash the router.

Software Versions and Fixes

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 - The 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 http://www.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/. +-------------------------------------------------------------------------+ | Major | Description | Availability of Repaired Releases* | | Release | or Platform | | |------------------------+------------------------------------------------| | Affected Earlier | Rebuild | Interim** | Maintenance | | Releases | | | | |------------------------+------------------------------------------------| | 11.1 and | | | | earlier, | Numerous | Not vulnerable | | all | | | | variants | | | |------------------------+------------------------------------------------| | Affected 11.2-Based | Rebuild | Interim** | Maintenance | | Releases | | | | |------------------------+------------------------------------------------| | 11.2 | Numerous | Not vulnerable | | variants | | | |------------------------+------------------------------------------------| | Affected 11.3-Based | Rebuild | Interim** | Maintenance | | Releases | | | | |------------------------+------------------------------------------------| | 11.3 | Numerous | Not vulnerable | | variants | | | |------------------------+------------------------------------------------| | Affected 12.0-Based | Rebuild | Interim** | Maintenance | | Releases | | | | |------------------------+------------+-----------------+-----------------| | | Core/ISP | | | | | | Support: | | | | | 12.0S | GSR, RSP, | 12.0(21)S3 | 12.0(21.03)S | | | | c7200, | | | | | | Cat6000 | | | | |----------+-------------+------------------------------------------------| | | Cable/ | Not planned | | 12.0SC | Broadband | | | | ISP: | Migrate to 12.1EC release | | | ubr7200 | | |----------+-------------+------------------------------------------------| | | 10000 ESR: | If using Pre1 card, then migrate to 12.0ST or | | 12.0SL | c10k | 12.0S | | | | For Pre card the date is not yet determined. | |----------+-------------+------------------------------------------------| | 12.0SP | c10720 | 12.0(20)SP3| 12.0(20.04)SP2 | | |----------+-------------+------------+-----------------+-----------------| | | MPLS/Tag | 12.0(19)ST5| | | | 12.0ST | Switching, | | | | | | GSR 12000, | 12.0(21)ST2| | | | | 7200, 7500 | | | | |----------+-------------+------------------------------------------------| | | Short-lived | | | | early | | | 12.0SX | deployment | To be determined | | | release | | | | 10000 ESR: | | | | c10k | | |----------+-------------+------------------------------------------------| | 12.0SY | | | 12.0(21.03)SY | 12.0(22)SY | |----------+-------------+------------+-----------------+-----------------| | | Short-lived | | | | | | early | | | | | 12.0WC | deployment | 12.0(5)WCa | | | | | release for | | | | | | 2900XL and | | | | | | 3500XL | | | | |----------+-------------+------------------------------------------------| | | Short-lived | Not planned | | 12.0XE | early | | | | deployment | Migrate to 12.2 release or later | | | release | | |------------------------+------------------------------------------------| | Affected 12.1-Based | Rebuild | Interim** | Maintenance | | Releases | | | | |------------------------+------------+-----------------+-----------------| | | General | | | | | | Deployment | | | | | 12.1 | (GD) | | 12.1(18.1) | 12.1(18) | | | candidate: | | | | | | all | | | | | | platforms | | | | |----------+-------------+------------+-----------------+-----------------| | | Core/ISP | | | | | 12.1E | Support: | | 12.1(12.5)E | 12.1(13)E | | | GSR, RSP, | | | | | | c7200 | | | | |----------+-------------+------------+-----------------+-----------------| | 12.1EA | Catalyst | 12.1(8)EA1c| | | | | 2950 | | | | |----------+-------------+------------+-----------------+-----------------| | | Early | | | | | | Deployment | | | | | 12.1EC | (ED): | | 12.1(12c)EC | | | | ubr7200, | | | | | | UBR Headend | | | | | | platforms | | | | |----------+-------------+------------+-----------------+-----------------| | | Early | | | | | | Deployment | | | | | 12.1EW | release, | | | 12.1(11b)EW | | | limited | | | | | | platforms | | | | |----------+-------------+------------+-----------------+-----------------| | | Early | | | | | | Deployment | | | | | 12.1EW | release, | | |12.1(11b)EW(0.46)| | | limited | | | | | | platforms | | | | |----------+-------------+------------+-----------------+-----------------| | 12.1EX | Catalyst | | | 12.1(11b)EX | | | 6000 | | | | |----------+-------------+------------------------------------------------| | | Short-lived | | | 12.1XF | early | Not planned Migrate to 12.1(5)T or later | | | deployment | | | | release | | |----------+-------------+------------------------------------------------| | | Short-lived | | | 12.1XG | early | Not planned Migrate to 12.1(1)T or later | | | deployment | | | | release | | |----------+-------------+------------------------------------------------| | | Short-lived | | | 12.1YB | early | Not planned Migrate to 12.1(2)T or later | | | deployment | | | | release | | |----------+-------------+------------------------------------------------| | | Short-lived | | | 12.1YC | early | Not planned Migrate to 12.1(4)T or later | | | deployment | | | | release | | |------------------------+------------------------------------------------| | Affected 12.2-Based | Rebuild | Interim** | Maintenance | | Releases | | | | |------------------------+------------+-----------------+-----------------| | | General | | | | | | Deployment | | | | | 12.2 | (GD) | | 12.2(10.4) | 12.2(10) | | | candidate: | | | | | | all | | | | | | platforms | | | | |----------+-------------+------------+-----------------+-----------------| | | Early | | | | | | Deployment | | | | | 12.2(4)B | for 6400, | | 12.2(13.3)B | | | | 7200 and | | | | | | 7400 | | | | |----------+-------------+------------------------------------------------| | | Early | | | | Deployment | | | 12.2BC | for uBR7000 | To be determined | | | and | | | | uBR10000 | | |----------+-------------+------------------------------------------------| | | Early | Not planned | | 12.2BY | Deployment | | | | release | Migrate to 12.2B releases | |----------+-------------+------------------------------------------------| | | Early | | | | | 12.2BZ | Deployment | | | 12.2(15)BZ | | | release | | | | |----------+-------------+------------+-----------------+-----------------| | | Early | | | | | | deployment | | | | | 12.2DA | release | | 12.2(11.4)DA | 12.2(12)DA | | | xDSL | | | | | | support: | | | | | | 6100, 6200 | | | | |----------+-------------+------------+-----------------+-----------------| | | Early | | | | | | deployment | | | | | 12.2MB | release for | 12.2(4)MB5 | | | | | 2600 and | | | | | | 7500 | | | | |----------+-------------+------------+-----------------+-----------------| | 12.2S | Core ISP | | 12.2(11.1)S | | | | support | | | | |----------+-------------+------------+-----------------+-----------------| | | Early | | | | | 12.2XC | deployment | 12.2(1a)XC5| | | | | release | | | | |----------+-------------+------------------------------------------------| | | ICS7750/820 | Not planned | | 12.2XD | /soho70 | | | | | Migrate to 12.2(8)YN or later | |----------+-------------+------------------------------------------------| | | 806, 828, | Not planned | | 12.2XE | soho78 | | | | | Migrate to 12.2(8)T or later | |----------+-------------+------------------------------------------------| | | 1700 820/ | Not planned | | 12.2XH | 800/soho70 | | | | | Migrate to 12.2(8)T or later | |----------+-------------+------------------------------------------------| | | | Not planned | | 12.2XI | 820/soho | | | | | Migrate to 12.2(12)T or later | |----------+-------------+------------------------------------------------| | | | Not planned | | 12.2XJ | 1700 | | | | | Migrate to 12.2(4)YB or later | |----------+-------------+------------------------------------------------| | 12.2XK | 820/soho | | | 12.2(2)XK3 | |----------+-------------+------------+-----------------+-----------------| | 12.2XL | 1700 820/ | | | 12.2(4)XL5 | | | 800/soho70 | | | | |----------+-------------+------------------------------------------------| | | Short-lived | Not planned | | 12.2XM | early | | | | deployment | Migrate to 12.2(8)YB or later | | | release | | |----------+-------------+------------------------------------------------| | | Short-lived | | | | | 12.2YA | early | 12.2(4)YA3 | | | | | deployment | | | | | | release | | | | |----------+-------------+------------------------------------------------| | | Short-lived | Not planned | | 12.2YB | early | | | | deployment | Migrate to 12.2(8)YB or later | | | release | | |----------+-------------+------------------------------------------------| | | Short-lived | | | | | 12.2YC | early | 12.2(4)YC4 | | | | | deployment | | | | | | release | | | | |----------+-------------+------------------------------------------------| | | Cisco | | | | Packet Data | | | 12.2YF | Serving | Release date to be decided | | | Node | | | | ics7700 | | |----------+-------------+------------------------------------------------| | | Short-lived | | | | | 12.2YG | early | | | 12.2(4)YG | | | deployment | | | | | | release | | | | |----------+-------------+------------+-----------------+-----------------| | | Short-lived | | | | | 12.2YH | early | | | 12.2(4)YH | | | deployment | | | | | | release | | | | |-------------------------------------------------------------------------| | Notes | |-------------------------------------------------------------------------| | * All dates are estimated and subject to change. | | | | ** Interim releases are subjected to less rigorous testing than regular | | maintenance releases, and may have serious bugs. | +-------------------------------------------------------------------------+ Obtaining Fixed Software
Cisco is offering free software upgrades to remedy this vulnerability for all affected customers. 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 the Cisco Connection Online Software Center at http://www.cisco.com/public/sw-center/sw-usingswc.shtm. 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. 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 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). In those cases, customers may only upgrade to a later version of the same release as indicated by the applicable row in the Software Versions and Fixes table. Cisco 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: [email protected] 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. 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 "[email protected]" or "[email protected]" for software upgrades. Workarounds =========== There is no workaround short of disabling the RTR responder. It is possible to mitigate the vulnerability by applying the ACL on the router. If you want to disable the RTR, you need to execute the following commands: Router#conf t Enter configuration commands, one per line. End with CNTL/Z. Router(config)#no rtr responder Router(config)#exit Router#copy running-config startup-config If you want to block all offending packets on your network edge, then you should create an ACL, or modify an existing one, to contain an entry resembling: Router#conf t Enter configuration commands, one per line. End with CNTL/Z. Router(config)#access-list 101 deny udp any any eq 1967 Router(config)#interface eth0 Router(config)#ip access-group 101 in In this example the interface eth0 is assumed to be facing toward the network edge. You will have to substitute it for the correct interface on your router. This will prevent any packet that is destined to the port 1967/UDP from entering your network. If you need to enable these packets to traverse your network, then the ACL must exclude only your internal routers. In addition to filtering packets at the network edge, you may apply filtering on the device itself and permit packets only from known good sources. This will contribute to the overall mitigation of this issue. Router#conf t Enter configuration commands, one per line. End with CNTL/Z. Router(config)#access-list 101 permit udp 10.0.0.1 10.0.0.10 eq 1967 Router(config)#access-list 101 deny udp any 10.0.0.10 eq 1967 Router(config)#interface eth0 Router(config)#ip access-group 101 in In this example, 10.0.0.1 is the legitimate source and 10.0.0.10 is the address of the router itself. Exploitation and Public Announcements
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory. Status of This Notice: FINAL
This is a final notice. Although Cisco cannot guarantee the accuracy of all statements in this advisory, all of the facts have been checked to the best of our ability. Cisco does not anticipate issuing updated versions of this advisory unless there is some material change in the facts. Should there be a significant change in the facts, Cisco may update this advisory. A stand-alone copy or paraphrase of the text of this security advisory that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors. Distribution ============ This advisory will be posted on Cisco's worldwide website at http:// www.cisco.com/warp/public/707/cisco-sa-20030515-saa.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. * [email protected] * [email protected] * [email protected] * [email protected] * [email protected] (includes CERT/CC) * [email protected] * [email protected] * comp.dcom.sys.cisco * Various internal Cisco mailing lists 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 | 2003- May-15, | Initial | | 1.0 | 15:00 UTC | public | | | (GMT) | 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. - -------------------------------------------------------------------------- This notice is Copyright 2003 by Cisco Systems, Inc. This notice may be redistributed freely after the release date given at the top of the text, provided that redistributed copies are complete and unmodified, and include all date and version information. - -------------------------------------------------------------------------- -----BEGIN PGP SIGNATURE----- Version: PGP 6.5.3 iQA/AwUBPsPU5HsxqM8ytrWQEQJV1wCaA1kCQri8r3mVgsEgOyPJDU7rACoAoNyb yPncmidbOU1jBDn9SkN9lAo6 =fa6X -----END PGP SIGNATURE-----

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