A TOCTOU (time-of-check time-of-use) race condition was found in the way libuser, a user and group account administration library, performed copying and removal of (user) directory trees. A local attacker, with permissions to write into particular directory, could use this flaw to conduct symbolic link attacks, leading to their ability to alter / remove directories outside of this directory (tree), if this directory was simultaneously modified (copied or removed) via libuser functionality.
This issue was found by Florian Weimer of Red Hat Product Security Team.
This issue affects the versions of the libuser package, as shipped with Red Hat Enterprise Linux 5 and 6.
This issue affects the versions of the libuser package, as shipped with Fedora release of 16 and 17.
This issue has been assigned CVE-2012-5630
Created libuser tracking bugs for this issue
Affects: fedora-all [bug 928846]
CVE-2012-5630 and CVE-2012-5644 were addressed upstream via the following set of commits (This also includes a some code refactoring, functionality changes and some minor cleanups):
Minimal backport to fedora version of libuser avoiding other code cleanups:
libuser-0.58-3.fc18 has been pushed to the Fedora 18 stable repository. If problems still persist, please make note of it in this bug report.
Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.