USN-235-1 fixed a vulnerability in sudo’s handling of environment variables. Tavis Ormandy noticed that sudo did not filter out the PYTHONINSPECT environment variable, so that users with the limited privilege of calling a python script with sudo could still escalate their privileges.
For reference, this is the original advisory:
9 January 2006
A security issue affects these releases of Ubuntu and its derivatives:
USN-235-1 fixed a vulnerability in sudo’s handling of environment variables. Tavis Ormandy noticed that sudo did not filter out the PYTHONINSPECT environment variable, so that users with the limited privilege of calling a python script with sudo could still escalate their privileges.
For reference, this is the original advisory:
Charles Morris discovered a privilege escalation vulnerability in sudo. On executing Perl scripts with sudo, various environment variables that affect Perl’s library search path were not cleaned properly. If sudo is set up to grant limited sudo execution of Perl scripts to normal users, this could be exploited to run arbitrary commands as the target user.
This security update also filters out environment variables that can be exploited similarly with Python, Ruby, and zsh scripts.
Please note that this does not affect the default Ubuntu installation, or any setup that just grants full root privileges to certain users.
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.
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