A vulnerability has been reported in Apache, which can be exploited by malicious people to conduct HTTP request smuggling attacks.

The vulnerability is caused due to an error in the handling of malformed HTTP requests with both "Transfer-Encoding" and "Content-Length" headers and can be exploited to cause Apache to forward malicious HTTP requests in the HTTP body, which will be processed as a separate HTTP requests by the receiving server.

Successful exploitation allows poisoning of the web proxy cache or bypass of certain web application firewall protections, but requires that Apache is configured as a web proxy.

An off-by-one error has also been reported in mod_ssl when printing debug information and configured to use a malicious CRL (Certificate Revocation List). An RFC 2616 non-compliance error in handling TRACE requests has also been reported.

The vulnerability has been reported in versions prior to 1.3.34, in version 2.0.35 through 2.0.37, 2.0.39, 2.0.40, and in version 2.0.42 through 2.0.54.

Solution
Update to the fixed version.
Further details available in Customer Area

Provided and/or discovered by
HTTP request smuggling reported by:
Watchfire

CRL issue reported by:
Marc Stern

Changelog
Further details available in Customer Area

Original Advisory
Apache.org:
http://www.apache.org/dist/httpd/Announcement2.0.html
http://www.apache.org/dist/httpd/Announcement1.3.html
http://www.apache.org/dist/httpd/CHANGES_1.3

Deep Links
Links available in Customer Area