Sourcefire, the creator of Snort and a provider of intelligent cybersecurity solutions, has announced that its Vulnerability Research Team (VRT) protects customers against the recently released “Apache Killer” tool, as well as attacks against the underlying vulnerability that enables it.

Functionality to detect the bug has existed for several years in both the Sourcefire IPS and open source Snort; in addition, the VRT also supplemented this protection this week with a new rule that specifically detects this new exploit and helps administrators identify the specific tool being used to attack them.

Using large malformed HTTP headers, Apache Killer allows an attacker to use a single PC to perform a denial of service attack. This attack is easily detected by the Snort engine’s HTTP Inspect preprocessor, which has an option to block oversized HTTP headers. Since many different attacks, against many different types of web servers, have used different types of large HTTP headers over the years, this functionality was made available by Sourcefire in order to proactively detect new vulnerabilities, as was the case with the Apache Killer tool.

In addition to this existing Snort engine functionality, the VRT also created a new rule (GID 1, SID 19825) for the Sourcefire IPS and Snort. This rule looks for HTTP “Range:” headers broken in the specific way necessary to trigger the vulnerability used by Apache Killer, providing users with the ability to detect and block the Apache Killer exploit even if they have chosen not to use the pre-existing oversized HTTP header detection functionality.

“Our solution to Apache Killer is a great example of the enormous amount of protocol intelligence and deep packet inspection capability in the Snort engine,” said Matt Watchinski, vice president of Vulnerability Research at Sourcefire. “By allowing customers to identify anomalous network traffic at a general level, the Snort engine provides detection ahead of the threat for a variety of new exploits. This flexibility gives network defenders the time they need to patch their networks, as well as protection in cases where a patch is not yet available, as with Apache Killer.”

For ongoing information on the Sourcefire’s coverage for this issue, please visit the Sourcefire VRT Blog.

The VRT is a group of leading-edge network security experts working around the clock to proactively discover, assess and respond to the latest trends in hacking activities, intrusion attempts and vulnerabilities. Some of the most renowned security professionals in the industry, including the authors of several standard security reference books, are members of the Sourcefire VRT. This team is also supported by the vast resources of the open source Snort community, making it the largest group dedicated to vulnerability research and advances in the network security industry.