Apache 2, mod_dav: Multiple vulnerabilities

Background

The Apache HTTP server is one of most popular web servers on the internet. mod_ssl provides SSL v2/v3 and TLS v1 support for it and mod_dav is the Apache module for Distributed Authoring and Versioning (DAV).

Description

A potential infinite loop has been found in the input filter of mod_ssl (CAN-2004-0748) as well as a possible segmentation fault in the char_buffer_read function if reverse proxying to a SSL server is being used (CAN-2004-0751). Furthermore, mod_dav, as shipped in Apache httpd 2 or mod_dav 1.0.x for Apache 1.3, contains a NULL pointer dereference which can be triggered remotely (CAN-2004-0809). The third issue is an input validation error found in the IPv6 URI parsing routines within the apr-util library (CAN-2004-0786). Additionally a possible buffer overflow has been reported when expanding environment variables during the parsing of configuration files (CAN-2004-0747).

Impact

A remote attacker could cause a Denial of Service either by aborting a SSL connection in a special way, resulting in CPU consumption, by exploiting the segmentation fault in mod_ssl or the mod_dav flaw. A remote attacker could also crash a httpd child process by sending a specially crafted URI. The last vulnerabilty could be used by a local user to gain the privileges of a httpd child, if the server parses a carefully prepared .htaccess file.

Workaround

There is no known workaround at this time.

Resolution

All Apache 2 users should upgrade to the latest version:

 # emerge sync

 # emerge -pv ">=www-servers/apache-2.0.51"
 # emerge ">=www-servers/apache-2.0.51"

All mod_dav users should upgrade to the latest version:

 # emerge sync

 # emerge -pv ">=net-www/mod_dav-1.0.3-r2"
 # emerge ">=net-www/mod_dav-1.0.3-r2"