ovt has reported a vulnerability in Cisco Secure ACS (Access Control Server), which potentially can be exploited by malicious people to bypass certain security restrictions.

The vulnerability is caused due to a design error in the Downloadable IP ACL (Access Control List) feature. This can be exploited by malicious people who knows the name of a Downloadable IP ACL configured on the ACS server to authenticate to the RAS/NAS (Remote Access Server/Network Access Server) by using the name of that ACL as their user name.

Successful exploitation requires that the attacker knows the name of the Downloadable IP ACL e.g. by sniffing network traffic between the RAS/NAS and the ACS server.

Solution
The vulnerability has been fixed in the following versions.
Further details available to Secunia VIM customers

Provided and/or discovered by
ovt

Original Advisory
Cisco:
http://www.cisco.com/en/US/products/sw/secursw/ps2086/products_field_notice09186a00805bf1c4.shtml

Deep Links
Links available to Secunia VIM customers