Some vulnerabilities have been reported in Cisco IOS, which can be exploited by malicious people to cause a DoS (Denial of Service) and potentially compromise a vulnerable system.

1) An error exists in the processing of IP options in various IP packets (including some ICMP requests, PIMv2, PGM, and URD requests). This can be exploited to restart the device or ipv4_io process or potentially execute arbitrary code via a specially crafted IP Option field in a packet sent to a physical or virtual IPv4 address configured on the device.

2) A memory leak error in the processing of TCP packets can be exploited to cause the device to consume a large amount of memory over time and may lead to a degraded service via a specially crafted packet sent to a physical or virtual IPv4 address configured on the device.

3) An error in the processing of IPv6 Type 0 Routing headers can be exploited to crash the device via a specially crafted packet sent to an IPv6 address defined on the device.

Successful exploitation of this vulnerability requires that IPv6 is enabled.

Solution
Update to the latest version (please see the vendor's advisory for details).

Provided and/or discovered by
1) Reported by the vendor.
2) Reported by the vendor.
3) Arnaud Ebalard, EADS Corporate Research Center.

Changelog
Further details available to Secunia VIM customers

Original Advisory
Cisco Systems:
http://www.cisco.com/warp/public/707/cisco-sa-20070124-bundle.shtml
http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-ip-option.shtml
http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-tcp.shtml
http://www.cisco.com/warp/public/707/cisco-sa-20070124-IOS-IPv6.shtml

Other references
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers