The Cisco IOS Stack Group Bidding Protocol (SGBP) feature in certain versions of Cisco IOS software is vulnerable to a remotely-exploitable denial of service condition. Devices that do not support or have not enabled the SGBP protocol are not affected by this vulnerability. Cisco has made free software available to address this vulnerability for affected customers. There are workarounds available to mitigate the effects of the vulnerability. This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20060118-sgbp .
The Cisco IOS Stack Group Bidding Protocol (SGBP) feature in certain versions of Cisco IOS software is vulnerable to a remotely-exploitable denial of service condition. Devices that do not support or have not enabled the SGBP protocol are not affected by this vulnerability.
Cisco has made free software available to address this vulnerability for affected customers. There are workarounds available to mitigate the effects of the vulnerability.
This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20060118-sgbp .
This section provides details on affected products.
This vulnerability affects any device that runs Cisco IOS and has
enabled the SGBP protocol. SGBP is enabled by defining a stack group, which is
done using the global IOS command sgbp group
The following examples demonstrate device configurations for which SGBP is enabled:
Router#show sgbp Group Name: test Ref: 0xA3728C00 Seed bid: default, 50, default seed bid setting
Or:
Router#show running-config | include sgbp sgbp group test_group
If your device displays output similar to either of the above examples, please consult the IOS software table below to determine whether your version of IOS is affected.
Cisco products that do not run IOS, do not contain support for SGBP, or do not have SGBP enabled are not affected by this vulnerability.
Systems on which SGBP is not supported or enabled will return either blank output or an error message. The following examples demonstrate device configurations that are not affected by this vulnerability:
Router#show sgbp Router#
Router#show sgbp Router#show sgbp ^ % Invalid input detected at '^' marker.
Multilink PPP (MLP) allows users to combine multiple PPP links into a single logical network connection, thus enabling on demand bandwidth allocation. When implemented across multiple device chassis, this is known as Multichassis Multilink PPP (MMP). The Stack Group Bidding Protocol is the mechanism by which devices participating in MMP locate each other and negotiate for a connection termination point.
The SGBP implementation provided by the Cisco Internetwork Operating System (IOS) is susceptible to a denial of service attack when presented with a crafted UDP packet. Sending such a packet to port 9900 of an affected device will cause it to freeze and stop responding to or passing traffic. After a delay, the system watchdog timer will detect this condition and force a reset of the device. The system recovery behavior will be controlled by the device configuration register; for example, the router may reload or drop to the ROM monitor.
This vulnerability is documented in Cisco bug ID CSCsb11124 ( registered customers only) .
This section describes workarounds for these vulnerabilities.
The access-list must then be applied to all interfaces using configuration commands such as:access-list 101 permit udp 192.168.10.0 0.0.0.255 192.168.10.0 0.0.0.255 port eq 9900 access-list 101 deny udp any 192.168.10.0 0.0.0.255 port eq 9900 access-list 101 permit ip any any
interface ethernet 0/0 ip access-group 101 in
! Do not police SGBP traffic from the trusted network access-list 140 deny udp 192.168.10.0 0.0.0.255 any eq 9900 ! Police SGBP traffic from untrusted hosts and networks access-list 140 permit udp any any eq 9900 ! Do not police any other type of traffic going to the router access-list 140 deny ip any any ! class-map match-all sgbp-class match access-group 140 ! policy-map control-plane-policy ! Drop all traffic that matches the class "sgbp-class" class sgbp-class drop ! control-plane service-policy input control-plane-policy
Note: CoPP is only available on certain platforms and IOS release trains. Additional information on the configuration and use of the CoPP feature can be found at the following URL:
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6586/ps6642/prod_white_paper0900aecd804fa16a.htmlCisco has provided updated software to address this vulnerability. For further details, please refer to the software table below.
When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center ("TAC") or your contracted maintenance provider for assistance.
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" 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).
For more information on the terms "Rebuild" and "Maintenance," consult the following URL: http://www.cisco.com/warp/public/620/1.html
Major Release |
Availability of Repaired Releases |
|
---|---|---|
Affected 12.0-Based Release |
Rebuild |
Maintenance |
12.0 |
Migrate to 12.2(32) |
|
12.0S |
12.0(28)S6 |
|
12.0(30)S5; available 23-Feb-06 |
||
12.0(31)S3; available 26-Jan-06 |
||
12.0(32)S; available 26-Jan-06 |
||
12.0SC |
Migrate to 12.3(13a)BC or later |
|
12.0T |
Migrate to 12.2(32) or later |
|
12.0XA |
Migrate to 12.2(32) or later |
|
12.0XC |
Migrate to 12.2(32) or later |
|
12.0XD |
Migrate to 12.2(32) or later |
|
12.0XE |
Migrate to 12.1(26)E5 |
|
12.0XG |
Migrate to 12.2(32) or later |
|
12.0XH |
Migrate to 12.2(32) or later |
|
12.0XI |
Migrate to 12.2(32) or later |
|
12.0XJ |
Migrate to 12.2(32) or later |
|
12.0XK |
Migrate to 12.2(32) or later |
|
12.0XL |
Migrate to 12.2(32) or later |
|
12.0XN |
Migrate to 12.2(32) or later |
|
12.0XR |
Migrate to 12.2(32) or later |
|
Affected 12.1-Based Release |
Rebuild |
Maintenance |
12.1 |
Migrate to 12.2(32) or later |
|
12.1AA |
Migrate to 12.2(32) or later |
|
12.1E |
12.1(26)E5 |
|
12.1EC |
Migrate to 12.3(13a)BC or later |
|
12.1EX |
Migrate to 12.1(26)E5 |
|
12.1EZ |
Migrate to 12.1(26)E5 |
|
12.1GA |
Migrate to 12.2(32) or later |
|
12.1GB |
Migrate to 12.2(32) or later |
|
12.1T |
Migrate to 12.2(32) or later |
|
12.1XA |
Migrate to 12.2(32) or later |
|
12.1XD |
Migrate to 12.2(32) or later |
|
12.1XH |
Migrate to 12.2(32) or later |
|
12.1XI |
Migrate to 12.2(32) or later |
|
12.1XL |
Migrate to 12.3(16) or later |
|
12.1XM |
Migrate to 12.3(16) or later |
|
12.1XQ |
Migrate to 12.3(16) or later |
|
12.1XS |
Migrate to 12.2(32) or later |
|
12.1XU |
Migrate to 12.2(32) or later |
|
12.1XW |
Migrate to 12.2(32) or later |
|
12.1XX |
Migrate to 12.2(32) or later |
|
12.1XY |
Migrate to 12.2(32) or later |
|
12.1XZ |
Migrate to 12.2(32) or later |
|
12.1YA |
Migrate to 12.3(16) or later |
|
12.1YB |
Migrate to 12.3(16) or later |
|
12.1YD |
Migrate to 12.3(16) or later |
|
Affected 12.2-Based Release |
Rebuild |
Maintenance |
12.2 |
12.2(32) |
|
12.2B |
Migrate to 12.3(11)T9 or later |
|
12.2BC |
Migrate to 12.3(13a)BC or later |
|
12.2BW |
Migrate to 12.3(16) or later |
|
12.2BY |
Migrate to 12.3(11)T9 or later |
|
12.2CX |
Migrate to 12.3(13a)BC or later |
|
12.2DD |
Migrate to 12.3(11)T9 or later |
|
12.2DX |
Migrate to 12.3(11)T9 or later |
|
12.2MC |
Migrate to 12.3(11)T9 or later |
|
12.2S |
12.2(14)S16; available 9-Feb-06 12.2(18)S and later are not vulnerable. |
|
12.2SU |
Migrate to 12.3(14)T6 |
|
12.2SY |
Migrate to 12.2SXD or later |
|
12.2SZ |
Migrate to 12.2S or later |
|
12.2T |
Migrate to 12.3(16) or later |
|
12.2XA |
Migrate to 12.3(16) or later |
|
12.2XB |
Migrate to 12.3(16) or later |
|
12.2XC |
Migrate to 12.3(11)T9 or later |
|
12.2XF |
Migrate to 12.3(13a)BC or later |
|
12.2XG |
Migrate to 12.3(16) or later |
|
12.2XK |
Migrate to 12.3(16) or later |
|
12.2XL |
Migrate to 12.3(16) or later |
|
12.2XS |
Migrate to 12.3(16) or later |
|
12.2XT |
Migrate to 12.3(16) or later |
|
12.2XV |
Migrate to 12.3(16) or later |
|
12.2YD |
Migrate to 12.3(11)T9 or later |
|
12.2YE |
Migrate to 12.2S or later |
|
12.2YN |
Migrate to 12.3(11)T9 or later |
|
12.2YT |
Migrate to 12.3(16) or later |
|
12.2YW |
Migrate to 12.3(11)T9 or later |
|
12.2YX |
Migrate to 12.3(14)T6 |
|
12.2YY |
Migrate to 12.3(11)T9 or later |
|
12.2YZ |
Migrate to 12.2S or later |
|
12.2ZA |
Migrate to 12.2SXD or later |
|
12.2ZB |
Migrate to 12.3(11)T9 or later |
|
12.2ZD |
Contact TAC |
|
12.2ZE |
Migrate to 12.3(16) or later |
|
12.2ZJ |
Migrate to 12.3(11)T9 or later |
|
12.2ZN |
Migrate to 12.3(11)T9 or later |
|
Affected 12.3-Based Release |
Rebuild |
Maintenance |
12.3 |
12.3(16) |
|
12.3B |
Migrate to 12.3(11)T9 or later |
|
12.3BC |
12.3(13a)BC |
|
12.3BW |
Migrate to 12.3(11)T9 or later |
|
12.3T |
12.3(11)T9 |
|
12.3(14)T6 |
||
12.3XB |
Migrate to 12.3(11)T9 or later |
|
12.3XD |
Migrate to 12.3(11)T9 or later |
|
12.3XF |
Migrate to 12.3(11)T9 or later |
|
12.3XH |
Migrate to 12.3(11)T9 or later |
|
12.3XI |
Contact TAC |
|
12.3XJ |
Migrate to 12.3(14)YX or later |
|
12.3XM |
Migrate to 12.3(14)T6 |
|
12.3XQ |
Migrate to 12.4(3) or later |
|
12.3XU |
Migrate to 12.4(4)T or later |
|
12.3XW |
Migrate to 12.3(14)YX or later |
|
12.3YF |
Migrate to 12.3(14)YX or later |
|
12.3YG |
Contact TAC |
|
12.3YJ |
Migrate to 12.3(14)YQ2 |
|
12.3YK |
Contact TAC |
|
12.3YM |
12.3(14)YM4 |
|
12.3YQ |
12.3(14)YQ2 |
|
12.3YT |
Contact TAC |
|
12.3YU |
Contact TAC |
|
12.3YX |
12.3(14)YX |
|
Affected 12.4-Based Release |
Rebuild |
Maintenance |
12.4 |
12.4(1b) |
|
12.4(3) |
||
12.4MR |
12.4(4)MR |
|
12.4T |
12.4(2)T3 |
|
12.4(4)T |
||
12.4XA |
12.4(2)XA |
|
12.4XB |
12.4(2)XB |
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
This vulnerability was discovered during internal testing.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
Revision 1.0 |
2006-January-18 |
Initial Public Release. |
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