VRT Advisories

VRT Rules 2007-04-03

Sourcefire VRT Update

Date: 2007-04-03


The Sourcefire VRT is aware of vulnerabilities affecting Real Networks Helix Server, IBM Lotus SameTime ActiveX control and an issue with ipv6 traffic handling on OpenBSD systems. This release also coincides with the release of Snort version

Sourcefire has addressed a number of potential security-related issues in Snort as reported by open source users, uncovered by internal investigations, and through third-party code audits.


OpenBSD IPv6 Fragmentation Overflow (CVE-2007-1365) and OpenBSD ICMP6 Denial of Service (CVE-2007-0343):
This release includes detection capabilities for attacks that attempt to exploit the IPv6 fragmentation overflow in OpenBSD-based operating systems.

Important Information about IPv6 Fragmentation Overflow Detection

Detection of traffic that attempts to exploit the IPv6 fragmentation overflow issue is enabled by default. If your Snort Sensors are deployed inline on your network, the malicious traffic is dropped automatically.

In order to disable this functionality, the following line needs to be added to snort.conf.

	config ipv6_frag: drop_bad_ipv6_frag off

Events generated by the preprocessor are identified as GID 123 and SIDs 9 and 10.

Real Networks Helix Server (CVE-2006-6026):
The Real Networks Helix Server fails to properly check user supplied data to the application. This may allow a remote attacker to overflow a fixed length buffer and execute code on a vulnerable host.

A rule to detect attacks targeting this vulnerability is included in this release and is identified as SID 10407.

IBM Lotus SameTime (CVE-2007-1784):
IBM Lotus SameTime fails to properly process user supplied input. This may allow an attacker to load DLL files and execute code by supplying suitable arguments to the loadLibrary function.

Rules to detect attacks targeting this vulnerability are included in this release and are identified as SIDs 10412 through 10417.

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.