Ilja van Sprundel discovered that passwd, when called with the -f, -g, or -s option, did not check the result of the setuid() call. On systems that configure PAM limits for the maximum number of user processes, a local attacker could exploit this to execute chfn, gpasswd, or chsh with root privileges.
This does not affect the default configuration of Ubuntu.
6 July 2006
A security issue affects these releases of Ubuntu and its derivatives:
Ilja van Sprundel discovered that passwd, when called with the -f, -g, or -s option, did not check the result of the setuid() call. On systems that configure PAM limits for the maximum number of user processes, a local attacker could exploit this to execute chfn, gpasswd, or chsh with root privileges.
This does not affect the default configuration of Ubuntu.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system upgrade is sufficient to effect the necessary changes.
Vulmon