Apache 2: Remote denial of service attack

Background

The Apache HTTP Server Project is an effort to develop and maintain an open-source HTTP server for modern operating systems. The goal of this project is to provide a secure, efficient and extensible server that provides services in tune with the current HTTP standards.

Description

A bug in the protocol.c file handling header lines will cause Apache to allocate memory for header lines starting with TAB or SPACE.

Impact

An attacker can exploit this vulnerability to perform a Denial of Service attack by causing Apache to exhaust all memory. On 64 bit systems with more than 4GB of virtual memory a possible integer signedness error could lead to a buffer based overflow causing Apache to crash and under some circumstances execute arbitrary code as the user running Apache, usually “apache”.

Workaround

There is no known workaround at this time. All users are encouraged to upgrade to the latest available version:

Resolution

Apache 2 users should upgrade to the latest version of Apache:

 # emerge sync

 # emerge -pv ">=www-servers/apache-2.0.49-r4"
 # emerge ">=www-servers/apache-2.0.49-r4"