VRT Advisories

VRT Rules 2005-04-18

Sourcefire VRT Certified Rule Update

Date: 2005-04-18


After continuing research into to the Microsoft Security Bulletin (MS05-017) released on Tuesday April 12 2005, the Sourcefire Vulnerability Research Team (VRT) has released a number of new rules to detect possible attempts to exploit the vulnerability. Additionally a rule to detect attempts to cause a Denial of Service using spoofed ICMP messages is also included in this rule pack.


Microsoft Message Queuing (MSMQ) enables messages to be queued for delivery at opportune times. Applications can query the message queue as they come online or at scheduled times.

A programming error in the MSMQ subsystem may present an attacker with the opportunity to overflow a fixed length buffer and execute code of their choosing on an affected host.

Rules to detect attacks against this vulnerability are included in this rule pack and are identified as sids 3554 through 3625.

The ICMP path MTU message informs a host that the packet size it has sent must be fragmented and will be dropped unless it is reduced to the designated MTU. It may be possible for an attacker to send a spoofed ICMP path MTU message to a host causing it to send very small packets. This may then result in the host experiencing a Denial of Service (DoS).

A rule to detect attacks against this vulnerability is included in this rule pack and is identified as sid 3626.

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.