Cisco Internetwork Operating System (IOS®) Software is vulnerable to a Denial of Service (DoS) and potentially an arbitrary code execution attack from a specifically crafted IPv6 packet. The packet must be sent from a local network segment. Only devices that have been explicitly configured to process IPv6 traffic are affected. Upon successful exploitation, the device may reload or be open to further exploitation. Cisco has released software updates that address this vulnerability. This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050729-ipv6.
Cisco Internetwork Operating System (IOS®) Software is vulnerable to a Denial of Service (DoS) and potentially an arbitrary code execution attack from a specifically crafted IPv6 packet. The packet must be sent from a local network segment. Only devices that have been explicitly configured to process IPv6 traffic are affected. Upon successful exploitation, the device may reload or be open to further exploitation.
Cisco has released software updates that address this vulnerability.This issue affects all Cisco devices running any unfixed version of Cisco IOS or Cisco IOS XR code that supports, and is configured for, IPv6. A system which supports IPv6, if not specifically configured for IPv6, is not affected. You can use the show ipv6 interface command to determine whether IPv6 is enabled on a system.
Sample output of the show ipv6 interface command is shown below for two systems, one not configured for IPv6 and one configured for IPv6.
An empty output or an error message will be displayed if IPv6 is disabled or unsupported on the system.
Router#show ipv6 int fa 0/0 -here you see blank output
In the example below the system is vulnerable.
Vulmon
Router#show ipv6 interface
Serial1/0 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::A8BB:CCFF:FE00:D200
Global unicast address(es):
2001:1:33::3, subnet is 2001:1:33::/64
Joined group address(es):
FF02::1
FF02::1:FF00:3
FF02::1:FF00:D200
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds
Router#
A router that has IPv6 enabled on a physical or logical interface is vulnerable to this issue even if ipv6 unicast-routing is globally disabled. The show ipv6 interface command can be used to determine whether IPv6 is enabled on any interface.
Note: Cisco 6500 and 7600 series systems that run 12.2(17a)SX, 12.2(17b)SXA or 12.2(17d)SXB based images automatically enable IPv6 on interfaces where Multi Protocol Label Switching (MPLS) is enabled. MPLS is enabled on an interface by the mpls ip or tag-switching ip commands. You can use the show ipv6 interface command to determine whether IPv6 is enabled on any interface.
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." 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 shows a product running IOS release 12.3(6) with an image name of C2600-JS-MZ:
Cisco Internetwork Operating System Software IOS (tm) C2600 Software (C2600-JS-MZ), Version 12.3(6), RELEASE SOFTWARE (fc1)
Additional information about Cisco IOS release naming can be found at http://www.cisco.com/web/about/security/intelligence/ios-ref.html.
A system that is running a Cisco IOS XR version prior to 3.2 is also affected by this vulnerability if configured for IPv6. The show ipv6 interface command can be used to identify whether IPv6 is enabled on a system running Cisco IOS XR.
Products that are not running Cisco IOS or Cisco IOS XR are not affected.
Products running any version of Cisco IOS that do not have IPv6 configured interfaces are not vulnerable.
No other Cisco products are currently known to be affected by these vulnerabilities.
IPv6 is the "Internet Protocol Version 6", designed by the Internet Engineering Task Force (IETF) to replace the current version Internet Protocol, IP Version 4 (IPv4).
A vulnerability exists in the processing of IPv6 packets. Crafted packets from the local segment received on logical interfaces (that is, tunnels including 6to4 tunnels) as well as physical interfaces can trigger this vulnerability. Crafted packets can not traverse a 6to4 tunnel and attack a box across the tunnel.
The crafted packet must be sent from a local network segment to trigger the attack. This vulnerability can not be exploited one or more hops from the IOS device.
This issue is documented in Cisco bug ID CSCef68324 ( registered customers only) for Cisco IOS, and CSCeh74956 ( registered customers only) for Cisco IOS XR.
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.
In networks where IPv6 is not needed but enabled, disabling IPv6 processing on an IOS device will eliminate exposure to this vulnerability. On a router which is configured for IPv6, this must be done by issuing the command no ipv6 enable and no ipv6 address on each interface.
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).
|
Major Release |
Availability of Repaired Releases |
|
|---|---|---|
|
Affected 12.0-Based Release |
Rebuild |
Maintenance |
|
12.0S |
12.0(26)S6 |
|
|
12.0(27)S5 |
||
|
12.0(28)S3 |
||
|
12.0(30)S2 |
12.0(31)S |
|
|
12.0SL |
Vulnerable; migrate to 12.0(31)S or later |
|
|
12.0ST |
Vulnerable; migrate to 12.0(31)S or later |
|
|
12.0SY |
Vulnerable; migrate to 12.0(31)S or later |
|
|
Affected 12.1-Based Release |
Rebuild |
Maintenance |
|
12.1XU |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1XV |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1YB |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1YC |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1YD |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1YE |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1YF |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1YH |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.1YI |
Vulnerable; migrate to 12.3(15) or later |
|
|
Affected 12.2-Based Release |
Rebuild |
Maintenance |
|
12.2B |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2BC |
12.2(15)BC2h |
|
|
12.2BW |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2BY |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2BX |
Vulnerable; migrate to 12.3(7)XI4 or later |
|
|
12.2BZ |
Vulnerable; migrate to 12.3(7)XI4 or later |
|
|
12.2CX |
Vulnerable; migrate to 12.3(13a)BC or later |
|
|
12.2CY |
Vulnerable; migrate to 12.3(13a)BC or later |
|
|
12.2DD |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2DX |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2EU |
12.2(20)EU1 |
|
|
12.2EW |
12.2(20)EW2 |
|
|
12.2EWA |
12.2(20)EWA2 12.2(25)EWA1 |
|
|
12.2EZ |
12.2(25)EZ1 |
|
|
12.2JA |
Vulnerable; migrate to 12.3(4)JA or later |
|
|
12.2JK |
12.2(15)JK4 |
|
|
12.2MB |
12.2(4)MB13b |
|
|
12.2MC |
12.2(15)MC2c |
|
|
12.2(15)MC1c is vulnerable; migrate to 12.4(2)MR |
||
|
12.2MX |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2S |
12.2(14)S14 |
|
|
12.2(18)S9 |
||
|
12.2(20)S8 |
||
|
12.2(25)S4 |
||
|
12.2SEB |
12.2(25)SEB3 |
|
|
12.2SEC |
12.2(25)SEC1 |
|
|
12.2SO |
Vulnerable; contact TAC |
|
|
12.2SU |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2SV |
12.2(18)SV3, 12.2(22)SV1, 12.2(23)SV1, 12.2(24)SV1, 12.2(25)SV2 |
12.2(26)SV |
|
12.2SW |
12.2(25)SW3a |
|
|
12.2SX |
Vulnerable; migrate to 12.2(17d)SXB8 or later |
|
|
12.2SXA |
Vulnerable; migrate to 12.2(17d)SXB8 or later |
|
|
12.2SXB |
12.2(17d)SXB8 |
|
|
12.2SXD |
12.2(18)SXD4 |
|
|
12.2SXE |
12.2(18)SXE1 |
|
|
12.2SY |
Vulnerable; migrate to 12.2(17d)SXB8 or later |
|
|
12.2SZ |
Vulnerable; migrate to 12.2(20)S8 or later |
|
|
12.2T |
12.2(13)T16 |
|
|
12.2(15)T16 |
||
|
12.2XA |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XB |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XC |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2XD |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XE |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XF |
Vulnerable; migrate to 12.3(13a)BC or later |
|
|
12.2XG |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XH |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XI |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XJ |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XK |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XL |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XM |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XN |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XQ |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XR |
Vulnerable; migrate to 12.3(4)JA or later |
|
|
12.2XT |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XU |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XW |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2XZ |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YA |
12.2(4)YA10 |
|
|
12.2YB |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YC |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YD |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YE |
Vulnerable; migrate to 12.2(25)S4 or later |
|
|
12.2YF |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YG |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YH |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YJ |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YK |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YL |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YM |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YN |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YO |
Vulnerable; migrate to 12.2(17d)SXB8 or later |
|
|
12.2YP |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2YQ |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YR |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YT |
Vulnerable; migrate to 12.2(15)T16 or later |
|
|
12.2YU |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YV |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YW |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YX |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YY |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2YZ |
Vulnerable; migrate to 12.2(20)S8 or later |
|
|
12.2ZA |
Vulnerable; migrate to 12.2(17d)SXB8 or later |
|
|
12.2ZB |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2ZC |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2ZD |
12.2(13)ZD3 |
|
|
12.2ZE |
Vulnerable; migrate to 12.3(15) or later |
|
|
12.2ZF |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2ZG |
Vulnerable; contact TAC |
|
|
12.2ZH |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2ZJ |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2ZL |
Vulnerable; contact TAC |
|
|
12.2ZN |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.2ZO |
Vulnerable; migrate to 12.2(15)T16 or later |
|
|
12.2ZP |
Vulnerable; migrate to 12.3(8)XY6 or later |
|
|
Affected 12.3-Based Release |
Rebuild |
Maintenance |
|
12.3 |
12.3(3h) |
|
|
12.3(5e) |
||
|
12.3(6e) |
||
|
12.3(9d) |
||
|
12.3(10d) |
||
|
12.3(12b) |
||
|
12.3(13a) |
12.3(15) |
|
|
12.3B |
12.3(5a)B5 |
|
|
12.3BC |
12.3(9a)BC6 |
12.3(13a)BC |
|
12.3BW |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.3JA |
12.3(4)JA |
|
|
12.3JK |
12.3(2)JK |
|
|
12.3T |
12.3(7)T9 |
|
|
12.3(8)T8 |
||
|
12.3(11)T5 |
||
|
12.3(14)T2 |
||
|
12.3XA |
12.3(2)XA4 |
|
|
12.3XB |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.3XC |
12.3(2)XC3 |
|
|
12.3XD |
Vulnerable; contact TAC |
|
|
12.3XE |
12.3(2)XE3 |
|
|
12.3XF |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.3XG |
12.3(4)XG4 |
|
|
12.3XH |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.3XI |
12.3(7)XI4 |
|
|
12.3XJ |
Vulnerable; migrate to 12.3(11)YF3 or later |
|
|
12.3XK |
12.3(4)XK3 |
|
|
12.3XL |
Vulnerable; contact TAC |
|
|
12.3XM |
Vulnerable; migrate to fixed 12.3(14)T2 or later |
|
|
12.3XQ |
12.3(4)XQ1 |
|
|
12.3XR |
12.3(7)XR4 |
|
|
12.3XS |
Vulnerable; migrate to 12.4(1) or later |
|
|
12.3XT |
Vulnerable; contact TAC |
|
|
12.3XU |
Vulnerable; migrate to 12.4(2)T or later |
|
|
12.3XW |
Vulnerable; migrate to 12.3(11)YF3 or later |
|
|
12.3XX |
Vulnerable; migrate to 12.4(1) or later |
|
|
12.3XY |
12.3(8)XY6 |
|
|
12.3YA |
12.3(8)YA1 |
|
|
12.3YD |
Vulnerable; migrate to 12.4(2)T |
|
|
12.3YF |
12.3(11)YF3 |
|
|
12.3YG |
12.3(8)YG2 |
|
|
12.3YH |
Vulnerable; migrate to 12.3(8)YI1 or later |
|
|
12.3YI |
12.3(8)YI1 |
|
|
12.3YJ |
12.3(11)YJ |
|
|
12.3YK |
Vulnerable; contact TAC |
|
|
12.3YQ |
12.3(14)YQ1 |
|
|
12.3YS |
12.3(11)YS |
|
|
12.3YT |
12.3(14)YT |
|
|
12.3YU |
12.3(14)YU |
|
|
Affected 12.4-Based Release |
Rebuild |
Maintenance |
|
12.4 |
12.4(1) |
|
|
12.4MR |
12.4(2)MR |
|
|
12.4T |
12.4(2)T |
|
|
Product |
First Fixed Release |
|---|---|
|
Cisco IOS XR |
IOS XR 3.2 Contact TAC to obtain SMU AA01233 for IOS XR 3.0.1. Contact TAC to obtain SMU AA01234 for IOS XR 3.1.0. |
For further information on the terms "Rebuild" and "Maintenance, " please consult the following URL: http://www.cisco.com/web/about/security/intelligence/ios-ref.html
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 1.8 |
2005-August-11 |
Status changed from Interim to Final. |
|
Revision 1.7 |
2005-August-05 |
Software Versions and Fixes table updated for Cisco IOS XR. |
|
Revision 1.6 |
2005-August-03 |
Added a note to the Affected Products section. Software Versions and Fixes table updated for 12.2EZ. |
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A stand-alone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.