Ubuntu 4.10 / 5.04 : apache2, libapache-mod-ssl vulnerabilities (USN-177-1)
Critical Nessus Plugin ID 20587
SynopsisThe remote Ubuntu host is missing one or more security-related patches.
DescriptionApache 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.
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.
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).
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected packages.