USN-177-1: Apache 2 vulnerabilities

7 September 2005

apache2, libapache-mod-ssl vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 5.04
  • Ubuntu 4.10

Software Description

Details

Apache did not honour the “SSLVerifyClient require” directive within a <Location> block if the surrounding <VirtualHost> block contained a directive “SSLVerifyClient optional”. This allowed clients to bypass client certificate validation on servers with the above configuration. (CAN-2005-2700)

Filip Sneppe discovered a Denial of Service vulnerability in the byte range filter handler. By requesting certain large byte ranges, a remote attacker could cause memory exhaustion in the server. (CAN-2005-2728)

The updated libapache-mod-ssl also fixes two older Denial of Service vulnerabilities: A format string error in the ssl_log() function which could be exploited to crash the server (CAN-2004-0700), and a flaw in the SSL cipher negotiation which could be exploited to terminate a session (CAN-2004-0885). Please note that Apache 1.3 and libapache-mod-ssl are not officially supported (they are in the “universe” component of the Ubuntu archive).

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 5.04
apache2-mpm-perchild
apache2-mpm-prefork
apache2-mpm-threadpool
apache2-mpm-worker
libapache-mod-ssl
Ubuntu 4.10
apache2-mpm-perchild
apache2-mpm-prefork
apache2-mpm-threadpool
apache2-mpm-worker
libapache-mod-ssl

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

References