VRT Advisories

VRT Rules 2005-06-29

Sourcefire VRT Certified Rules Update

Date: 2005-06-29


The Sourcefire Vulnerability Research Team (VRT) has learned of serious vulnerabilities affecting IBM Websphere and Squid HTTP proxy server.


A Squid proxy server can cache resources to make access to them more efficient. A malformed request sent to a Squid proxy server may be interpreted and processed differently than the actual responding web server. A particular malformed request that contains two "Content-Length" header fields can be used to try to poison the cache by causing the Squid proxy server and an upstream server to process the contents differently.

A Rule to detect attacks against this vulnerability is included in this rule pack and is identified as sid 3694.

IBM WebSphere may use form-based authentication to permit access to applications. The CGI variables j_username and j_password are used for this authentication process. Overly long values passed to these variables can cause a buffer overflow and the subsequent execution of arbitrary code on the vulnerable server. This is due to a failure in the code to accommodate wide-character expansion for the receiving buffer.

A rule to detect attacks against this vulnerbility is included in this rule pack and is identified as sid 3693.

Rule Pack Summary:

For a complete list of new and modified rules, click here.


Sourcefire VRT rule packs often utilize enhancements made to Snort. Operators should upgrade to the latest revision or patch level for Snort to ensure these enhancements are available before using these rules.

About the VRT:

The Sourcefire VRT is a group of leading edge intrusion detection and prevention experts working to proactively discover, assess and respond to the latest trends in hacking activity, intrusion attempts and vulnerabilities. This team is also supported by the vast resources of the open source Snort community, making it the largest group dedicated to advances in network security industry.