Christian Eibl discovered that the TeX filter in Moodle allowed any function to be used. An authenticated remote attacker could post a specially crafted TeX formula to execute arbitrary TeX functions, potentially reading any file accessible to the web server user, leading to a loss of privacy. (CVE-2009-1171, MSA-09-0009)
The problem can be corrected by updating your system to the following package versions:
24 June 2009
A security issue affects these releases of Ubuntu and its derivatives:
Christian Eibl discovered that the TeX filter in Moodle allowed any function to be used. An authenticated remote attacker could post a specially crafted TeX formula to execute arbitrary TeX functions, potentially reading any file accessible to the web server user, leading to a loss of privacy. (CVE-2009-1171, MSA-09-0009)
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.
After a standard system upgrade you need to access the Moodle instance and accept the database update to clear any invalid cached data.