Vulnerability Note VU#274760
Cisco IOS fails to properly process specially crafted IPv6 packets
OverviewCisco IOS fails to properly process IPv6 packets with specially crafted routing headers. Successful exploitation of this vulnerability may allow an attacker to execute code, or create a denial-of-service condition.
I. DescriptionInternet Protocol version 6 (IPv6) is a IP standard that is designed to replace the Internet Protocol version 4 (IPv4). IPv6 Type 0 Routing headers can store multiple addresses and are processed by routers for generalized source routing.
Cisco IOS software contains a vulnerability that occurs when proccessing IPv6 Type 0 Routing headers. An attacker may be able to trigger this vulnerability by sending an IP packet with a speciallly crafted IPv6 Type 0 Routing header to a vulnerable system.
Cisco states that Type 2 Routing headers, commonly used in Mobile IPv6 implementations, cannot be used to trigger this vulnerability.
Note that a device with a configured IPv6 address accepting IPv6 packets that are tunneled over an IPv4 connection may also be vulnerable.
II. ImpactA remote unauthenticated attacker may be able to execute arbitrary code on an affected device, or create a denial of service condition.
III. SolutionUpgrade
See the Software Version and Fixes section of Cisco Security Advisory 20070124 for information on available upgrades.
Restrict Access
Restricitng public access to vulnerable systems or blocking IPv6 packets with Type 0 Routing headers by implementing management VLANs or Access Control Lists may mitigate this vulnerability. Note that networks not using mobile IPv6 can filter all packets that contain Routing headers.
Disable Services
Disabling IPv6 functionality on devices using IPv4 may prevent this vulnerability from being exploited.
For more information about these and other workarounds, see the workarounds section of Cisco Security Advisory 20070124 and Cisco PSIRT Document 81722.
Systems Affected
References
http://www.cisco.com/warp/public/707/cisco-sa-20070124-IOS-IPv6.shtml
http://www.cisco.com/en/US/products/products_security_response09186a00807cb0df.html#routers
http://www.cisco.com/en/US/products/products_security_advisory09186a00807cb157.shtml#workarounds
http://www.cisco.com/web/about/ac123/ac147/ac174/ac197/about_cisco_ipj_archive_article09186a00800c830a.html
http://www.cisco.com/en/US/products/products_security_response09186a00807cb0df.html
http://www.cisco.com/warp/public/707/cisco-sa-20070124-bundle.shtml
http://en.wikipedia.org/wiki/IPv6
http://en.wikipedia.org/wiki/Mobile_IPv6
http://www.ietf.org/rfc/rfc2460.txt
http://secunia.com/advisories/23867/
http://www.securityfocus.com/bid/22210
http://www.cisco.com/en/US/products/sw/iosswrel/products_ios_cisco_ios_software_category_home.html
Credit
Thanks to Cisco for information used in this report.
This document was written by Ryan Giobbi.
Other Information
| Date Public | 01/24/2007 |
| Date First Published | 01/24/2007 04:37:48 PM |
| Date Last Updated | 01/25/2008 |
| CERT Advisory | |
| CVE-ID(s) | |
| NVD-ID(s) | |
| US-CERT Technical Alerts | |
| Metric | 5.94 |
| Document Revision | 26 |
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