July 16, 2003
A denial of service vulnerability has been reported to exist in all hardware platforms that run Cisco IOS versions 11.x through 12.x. This issue may be triggered by a sequence of specifically crafted IPV4 packets. A power cycling of an affected device is required to regain normal functionality.
Implement multiple redundant layers of security.
Multiple diverse layers of network access control should be implemented to limit the consequences of one layer failing and to protect network devices from attacks by malicious parties. Redundant network devices should be deployed to mitigate the consequences of attacks that affect the availability of network resources.
Further information regarding obtaining and applying fixes and workarounds can be found in the attached Cisco security advisory (cisco-sa-20030717). Some releases may not be available at this time, so users should also consult the advisory for further details regarding the availability of fixed releases.
The Symantec DeepSight Threat Management System has witnessed that this vulnerability is currently being exploited in the wild and considers it a high risk. Patches should be applied immediately and in situations where this is not possible, administrators are advised to evaluate the applicability of all available workarounds.
** August 02, 2003 - Cisco has released revision 1.13 of the advisory detailing additional fix information for 12.0T and 12.1EC. See referenced advisory for additional details.
This vulnerability was announced by the vendor.
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