nginx Server Denial of Service (May 24, 2013)
nginx is an open source web server and a reverse proxy server for HTTP, SMTP, POP3, and IMAP protocols, with a strong focus on high concurrency, performance and low memory usage. nginx implements the HTTP protocol version 1.1 as defined in RFC 2616.
A denial of service vulnerability exists in nginx. Specifically, the vulnerability is due to an input validation error when handling chunked requests or responses from a peer. A remote attacker could exploit this vulnerability by sending a crafted HTTP request/response to the target server. Successful exploitation would terminate the process and cause a denial of service condition. Dell SonicWALL has released IPS signatures to detect and block specific exploitation attempts targeting this vulnerability. The signatures are listed below:- 3113 Suspicious HTTP Transfer-Encoding Header 1c
- 4590 Suspicious HTTP Transfer-Encoding Header 1s
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.
