Advisory ID: cisco-sa-20050729-ipv6
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050729-ipv6
Revision 2.0
For Public Release 2005 July 29 08:00 UTC (GMT)
Contents
Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Versions and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of this Notice: Final
Distribution
Revision History
Cisco Security Procedures
Summary
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 free software updates that address this vulnerability.This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050729-ipv6.
Affected Products
Vulnerable Products
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.
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 Confirmed Not Vulnerable
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.
Details
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.
Vulnerability Scoring Details
Impact
Successful exploitation of the vulnerability on Cisco IOS may result in a reload of the device or execution of arbitrary code. Repeated exploitation could result in a sustained DoS attack or execution of arbitrary code on Cisco IOS devices.
Successful exploitation of the vulnerability on Cisco IOS-XR may result in a restart of the IPv6 neighbor discovery process. A restart of this process will only affect IPv6 traffic passing through the system. All other processes and traffic will be unaffected. Repeated exploitation could result in a sustained DoS attack on IPv6 traffic.
Software Versions and Fixes
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
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.
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.
Obtaining Fixed Software
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/en/US/docs/general/warranty/English/EU1KEN_.html , or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml .
Do not contact psirt@cisco.com or security-alert@cisco.com for software upgrades
Customers with Service Contracts
Customers using Third Party Support Organizations
The effectiveness of any workaround or fix 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 or fix is the most appropriate for use in the intended network before it is deployed.
Customers without Service Contracts
Customers who purchase direct from Cisco but do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire 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@cisco.com
Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.
Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.
Exploitation and Public Announcements
Status of this Notice: Final
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 in the following section is an uncontrolled copy, and may lack important information or contain factual errors.
Distribution
This advisory is posted on Cisco's worldwide website at:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050729-ipv6
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@cisco.com
- first-teams@first.org
- bugtraq@securityfocus.com
- vulnwatch@vulnwatch.org
- cisco@spot.colorado.edu
- cisco-nsp@puck.nether.net
- full-disclosure@lists.grok.org.uk
- comp.dcom.sys.cisco@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 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. |
|
Revision 1.5 |
2005-August-02 |
Software Versions and Fixes table updated for 12.2JK, 12.2MC, 12.2ZD, 12.3XA, 12.3XE, 12.3XG, and 12.3XK; removed 12.2CZ. |
|
Revision 1.4 |
2005-August-01 |
Software Versions and Fixes table updated for 12.2BC, 12.2EZ, 12.2SEB, and 12.2SW. |
|
Revision 1.3 |
2005-July-31 |
Software Versions and Fixes table updated. |
|
Revision 1.2 |
2005-July-30 |
IOS XR added to Affected Products. Wording changes made in the Workarounds section. Software Versions and Fixes table updated. |
|
Revision 1.1 |
2005-July-29 |
Software Versions and Fixes table updated. First paragraph in the Vulnerable Products section updated. |
|
Revision 1.0 |
2005-July-29 |
Initial public 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/en/US/products/products_security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt.