Vulnerability Assessment & Network Security Forums

If through a vulnerability assessment, a network security issue is detected for the vulnerability below, applying the appropriate security patches in a timely matter is very important. If you have detected that your system has already been compromised, following CERT's Network Security recovery document will assist with recommended steps for system recovery.

Home >> Browse Vulnerability Assessment Database >> Gentoo Local Security Checks >> [GLSA-200509-15] util-linux: umount command validation error

Vulnerability Assessment Details

[GLSA-200509-15] util-linux: umount command validation error

Vulnerability Assessment Summary
util-linux: umount command validation error

Detailed Explanation for this Vulnerability Assessment
The remote host is affected by the vulnerability described in GLSA-200509-15
(util-linux: umount command validation error)

When a regular user mounts a filesystem, they are subject to
restrictions in the /etc/fstab configuration file. David Watson
discovered that when unmounting a filesystem with the '-r' option, the
read-only bit is set, while other bits, such as nosuid or nodev, are
not set, even if they were previously.

Impact

An unprivileged user facing nosuid or nodev restrictions can
umount -r a filesystem clearing those bits, permiting applications to be
executed suid, or have device nodes interpreted. In the case where the
user can freely modify the contents of the filesystem, privilege
escalation may occur as a custom program may execute with suid
permissions.

Workaround

Two workarounds exist, first, the suid bit can be removed from the
umount utility, or users can be restricted from mounting and unmounting
filesystems in /etc/fstab.

References:
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=2005-2876

Solution:
All util-linux users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-apps/util-linux-2.12q-r3"

Network Security Threat Level: High

Networks Security ID:

Vulnerability Assessment Copyright: (C) 2005 Michel Arboi

Cables, Connectors