VRT Advisories

VRT Rules 2007-07-31

Sourcefire VRT Rules Update

Date: 2007-07-31


The Sourcefire VRT is aware of a vulnerability affecting hosts using Microsoft Excel. This release also includes additions to the spyware-put and backdoor rule categories.


Microsoft Security Bulletin MS07-036:
A memory corruption vulnerability exists in the way Microsoft Excel processes files. The vulnerability is a result of insufficient data validation while processing the Version field in a BOF record. A remote attacker can exploit this vulnerability by enticing the target user to open a crafted Excel file, potentially causing arbitrary code to be injected and executed in the security context of the current user.

A rule to detect attacks targeting this vulnerability is included in this release and is identified as SID 12184.

In addition, as a result of ongoing research, the VRT has added rules to the backdoor and spyware-put rule categories.

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 the network security industry.