VRT Advisories

VRT Rules 2006-03-29

Sourcefire VRT Update

Date: 2006-03-29


The Sourcefire VRT has learned of vulnerabilities affecting hosts using Sendmail and has identified additional attack vectors for vulnerabilities affecting Microsoft HTML Help Workshop.


A race condition exists in versions of Sendmail, this vulnerability may allow a remote attacker to execute code of their choosing on an affected server. A programming error in the way that Sendmail handles asynchronous signals may allow an attacker to overflow a fixed length buffer by supplying a large amount of data in an email header.

A rule to detect attacks targeting this vulnerability is included in this update and is identified as sid 5739.

HTML Help Workshop fails to properly validate file contents before reading and putting information into a fixed length buffer. A malicious file may contain information that could overflow the buffer and execute code on the affected system.

Rules to detect attacks targeting this vulnerability are included in this update and are identified as sids 5740 and 5741.

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.