Download Apache 1.3.37, 2.0.59 and 2.2.3

Apache has released new versions of its web server software in both the 1.3, 2.0 and 2.2 branch. A serious so-called ‘off-by-one’ error has been discovered in the mod_rewrite. This bug is in all versions and has existed in version 1.3 since 1.3.28, in version 2.0 since 2.0.46 and in version 2.2 since the very beginning. More information about this bug can be found in the release notes:

The following potential security flaws are addressed;

CVE-2006-3747: An off-by-one flaw exists in the Rewrite module, mod_rewrite, as shipped with Apache 1.3 since 1.3.28, 2.0 since 2.0.46, and 2.2 since 2.2.0.

Depending on the manner in which Apache HTTP Server was compiled, this software defect may result in a vulnerability which, in combination with certain types of Rewrite rules in the web server configuration files, could be triggered remotely. For vulnerable builds, the nature of the vulnerability can be denial of service (crashing of web server processes) or potentially allow arbitrary code execution. This issue has been rated as having important security impact by the Apache HTTP Server Security Team.

This flaw does not affect a default installation of Apache HTTP Server. Users who do not use, or have not enabled, the Rewrite module mod_rewrite are not affected by this issue. This issue only affects installations using a Rewrite rule with the following characteristics:

• The RewriteRule allows the attacker to control the initial part of the rewritten URL (for example if the substitution URL starts with $1)
• The RewriteRule flags do NOT include any of the following flags: Forbidden (F), Gone (G), or NoEscape (NE).

Please note that ability to exploit this issue is dependent on the stack layout for a particular compiled version of mod_rewrite. If the compiler used to compile Apache HTTP Server has added padding to the stack immediately after the buffer being overwritten, it will not be possible to exploit this issue, and Apache HTTP Server will continue operating normally.[break]