The USN-1140-1 PAM update caused cron to stop working.
USN-1140-1 fixed vulnerabilities in PAM. A regression was found that caused cron to stop working with a “Module is unknown” error. As a result, systems configured with automatic updates will not receive updates until cron is restarted, these updates are installed or the system is rebooted. This update fixes the problem.
31 May 2011
A security issue affects these releases of Ubuntu and its derivatives:
The USN-1140-1 PAM update caused cron to stop working.
USN-1140-1 fixed vulnerabilities in PAM. A regression was found that caused cron to stop working with a “Module is unknown” error. As a result, systems configured with automatic updates will not receive updates until cron is restarted, these updates are installed or the system is rebooted. This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Marcus Granado discovered that PAM incorrectly handled configuration files with non-ASCII usernames. A remote attacker could use this flaw to cause a denial of service, or possibly obtain login access with a different users username. This issue only affected Ubuntu 8.04 LTS. (CVE-2009-0887)
It was discovered that the PAM pam_xauth, pam_env and pam_mail modules incorrectly handled dropping privileges when performing operations. A local attacker could use this flaw to read certain arbitrary files, and access other sensitive information. (CVE-2010-3316, CVE-2010-3430, CVE-2010-3431, CVE-2010-3435)
It was discovered that the PAM pam_namespace module incorrectly cleaned the environment during execution of the namespace.init script. A local attacker could use this flaw to possibly gain privileges. (CVE-2010-3853)
It was discovered that the PAM pam_xauth module incorrectly handled certain failures. A local attacker could use this flaw to delete certain unintended files. (CVE-2010-4706)
It was discovered that the PAM pam_xauth module incorrectly verified certain file properties. A local attacker could use this flaw to cause a denial of service. (CVE-2010-4707)
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 update will make all the necessary changes.
Vulmon