There is a remotely exploitable vulnerability in the way that Apache web servers (or other web servers based on their source code) handle data encoded in chunks. This vulnerability is present by default in configurations of Apache web server versions 1.2.2 and above, 1.3 through 1.3.24, and versions 2.0 through 2.0.36. The impact of this vulnerability is dependent upon the software version and the hardware platform the server is running on.
Apache is a popular web server that includes support for chunk-encoded data according to the HTTP 1.1 standard as described in RFC2616. There is a vulnerability in the handling of certain chunk-encoded HTTP requests that may allow remote attackers to execute arbitrary code.
The Apache Software Foundation has published an advisory describing the details of this vulnerability. This advisory is available on their web site at
For Apache versions 1.2.2 through 1.3.24 inclusive, this vulnerability may allow the execution of arbitrary code by remote attackers. Exploits are publicly available that claim to allow the execution of arbitrary code.
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The CERT/CC thanks Mark Litchfield for reporting this vulnerability to the Apache Software Foundation, and Mark Cox for reporting this vulnerability to the CERT/CC.
This document was written by Cory F. Cohen.