Two exploitable vulnerabilities involving setuid-enabled perl scripts have been discovered. The package “perl-suid” provides a wrapper around perl which allows to use setuid-root perl scripts, i.e. user-callable Perl scripts which have full root privileges.
Previous versions allowed users to overwrite arbitrary files by setting the PERLIO_DEBUG environment variable and calling an arbitrary setuid-root perl script. The file that PERLIO_DEBUG points to was then overwritten by Perl debug messages. This did not allow precise control over the file content, but could destroy important data. PERLIO_DEBUG is now ignored for setuid scripts. (CAN-2005-0155)
2 February 2005
A security issue affects these releases of Ubuntu and its derivatives:
Two exploitable vulnerabilities involving setuid-enabled perl scripts have been discovered. The package “perl-suid” provides a wrapper around perl which allows to use setuid-root perl scripts, i.e. user-callable Perl scripts which have full root privileges.
Previous versions allowed users to overwrite arbitrary files by setting the PERLIO_DEBUG environment variable and calling an arbitrary setuid-root perl script. The file that PERLIO_DEBUG points to was then overwritten by Perl debug messages. This did not allow precise control over the file content, but could destroy important data. PERLIO_DEBUG is now ignored for setuid scripts. (CAN-2005-0155)
In addition, calling a setuid-root perl script with a very long path caused a buffer overflow if PERLIO_DEBUG was set. This buffer overflow could be exploited to execute arbitrary files with full root privileges. (CAN-2005-0156)
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.
Vulmon