TITLE:
Cisco IOS System Timers Potential Arbitrary Code Execution

SECUNIA ADVISORY ID:
SA17413

VERIFY ADVISORY:
http://secunia.com/advisories/17413/

CRITICAL:
Moderately critical

IMPACT:
Security Bypass

WHERE:
>From remote

OPERATING SYSTEM:
Cisco IOS R12.x
http://secunia.com/product/50/
Cisco IOS R11.x
http://secunia.com/product/53/
Cisco IOS 12.x
http://secunia.com/product/182/
Cisco IOS 10.x
http://secunia.com/product/184/
Cisco IOS 11.x
http://secunia.com/product/183/

DESCRIPTION:
A vulnerability has been reported in Cisco IOS, which potentially can
be exploited by malicious people to bypass certain security
restrictions.

The vulnerability is caused due to an error in validating whether
certain system memory has been corrupted by a heap-based buffer
overflow before the internal operating system timers execute code
from the affected memory area. This can potentially be exploited to
execute arbitrary code in conjunction with some other heap-based
buffer overflow vulnerability.

The vulnerability has been reported to affect all Cisco products that
run Cisco IOS Software.

Note: The vendor has reported that the vulnerability was fixed as a
result of continued research related to the demonstration of an
exploit for the IPv6 vulnerability.

For more information:
SA16272

SOLUTION:
Fixes are available for IOS 12.0, 12.1, 12.2, 12.3 and 12.4 (see
patch matrix in vendor advisory).
http://www.cisco.com/warp/public/707/cisco-sa-20051102-timers.shtml#software

PROVIDED AND/OR DISCOVERED BY:
Reported by vendor.

ORIGINAL ADVISORY:
http://www.cisco.com/warp/public/707/cisco-sa-20051102-timers.shtml

OTHER REFERENCES:
SA16272:
http://secunia.com/advisories/16272/

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