Apache Range Header Processing DoS (Sep 1, 2011)


The Apache HTTP server is the most popular HTTP server software in use. It supports a variety of features, many implemented as compiled modules which extend the core functionality.

The Range header in HTTP/1.1 is used to request part of an entity; it improves efficiency when recovering from failed or incomplete transfers. The Range header may specify a single range of bytes, or a set of ranges within a single entity.

A memory exhaustion vulnerability exists in Apache HTTP Server. Specifically, the vulnerability happens when processing a Range header that expresses multiple overlapping ranges. A remote attacker could exploit this vulnerability by sending a series of crafted HTTP requests to the target server. Successful exploitation would exhaust available memory of the target server and cause a denial-of-service condition.

The vulnerability has been assigned as CVE-2011-3192.

SonicWALL has released an IPS signature to detect and block specific exploitation attempts targeting this vulnerability. The signature is listed below:

  • 6905 Apache HTTP Range Header DOS Attempt
Security News
The SonicWall Capture Labs Threat Research Team gathers, analyzes and vets cross-vector threat information from the SonicWall Capture Threat network, consisting of global devices and resources, including more than 1 million security sensors in nearly 200 countries and territories. The research team identifies, analyzes, and mitigates critical vulnerabilities and malware daily through in-depth research, which drives protection for all SonicWall customers. In addition to safeguarding networks globally, the research team supports the larger threat intelligence community by releasing weekly deep technical analyses of the most critical threats to small businesses, providing critical knowledge that defenders need to protect their networks.