VRT Advisories

VRT Rules 2005-04-05

Sourcefire VRT Certified Rule Update

Date: 2005-04-05


The Sourcefire Vulnerability Research Team (VRT) has learned of serious vulnerabilities affecting various implementations of Telnet.


The Telnet protocol can be used to remotely connect machines over a networked connection. A telnet client and server can negotiate various options such as the character set to be used in the communication exchange. Various environment variables can also be set by issuing commands from the client.

Programming errors in the telnet client code from various vendors may present an attacker with the opportunity to overflow a fixed length buffer.

Rules to detect attacks against this vulnerability are included in this rule pack and are identified as sids 3533 and 3537.

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.