Ruby WEBrick HTTP Request Smuggling Vulnerability

A request smuggling vulnerability has been identified in Ruby WEBrick, allowing remote attackers to send arbitrary HTTP requests. This issue arises from inconsistent parsing of HTTP header terminators in the 'read_headers' method, creating a flaw that can be exploited when WEBrick is behind a specific type of HTTP proxy.

Impact

Exploitation of this vulnerability allows for HTTP request smuggling, where an attacker can send malicious HTTP requests that are improperly handled by the server or an intermediary proxy.

Reproduction

The vulnerability can be reproduced by deploying Ruby WEBrick behind an HTTP proxy that does not correctly handle header terminators. Once this setup is in place, an attacker can craft requests that exploit the parsing flaw in WEBrick's 'read_headers' method, smuggling them through the proxy to the server.

Remediation

Ruby has released a patch for this vulnerability. Users should update to the latest version of WEBrick.