CVE-2011-2729: Commons Daemon fails to drop capabilities (Apache Tomcat)

Severity: Important

Vendor:
The Apache Software Foundation

Versions Affected:
Tomcat 7.0.0 to 7.0.19
Tomcat 6.0.30 to 6.0.32
Tomcat 5.5.32 to 5.5.33

Description:
Due to a bug in the capabilities code, jsvc (the service wrapper for
Linux that is part of the Commons Daemon project) does not drop
capabilities allowing the application to access files and directories
owned by superuser. This vulnerability only applies if:
a) Tomcat is running on a Linux operating system
b) jsvc was compiled with libcap
c) -user parameter is used
The Tomcat versions above shipped with source files for jsvc that
included this vulnerability.

Mitigation:
Affected users of all versions can mitigate these vulnerabilities by
taking any of the following actions:
a) upgrade to jsvc 1.0.7 or later
b) do not use -user parameter to switch user
c) recompile the jsvc without libcap support
Updated jsvc source is included in Apache Tomcat 7.0.20 and will be
included in the next releases of Tomcat 6.0.x and 5.5.x. Updated source
can be obtained from the Apache Commons Daemon project.

Credit:
This issue was identified by Wilfried Weissmann.