DistUpgrade/DistUpgradeMain.py in Update Manager, as used by Ubuntu 12.04 LTS, 11.10, and 11.04, uses weak permissions for (1) apt-clone_system_state.tar.gz and (2) system_state.tar.gz, which allows local users to obtain repository credentials.
https://exchange.xforce.ibmcloud.com/vulnerabilities/75727
http://www.ubuntu.com/usn/USN-1443-1
http://www.securityfocus.com/bid/53604
http://secunia.com/advisories/49230
http://launchpadlibrarian.net/105380733/update-manager_1%3A0.156.14.3_1%3A0.156.14.4.diff.gz