util-linux umount allows elevated privileges
| utillinux-umount-gain-privileges (22241) |  High Risk |
Description:
The util-linux package, included with multiple Linux distributions, could allow a local attacker to gain elevated privileges. A local attacker could use the -r option to remount the file system (if it is busy and unable to unmount completely) and force the unsafe remount, even if the file system is set up as read-only. If 'users' is selected in the fstab entry, an attacker could use this vulnerability to gain root privileges on the system.
Platforms Affected:
- Canonical, Ubuntu 4.10
- Canonical, Ubuntu 5.04
- Debian, Debian Linux 3.0
- Debian, Debian Linux 3.1
- Gentoo, Linux
- Kernel, util-linux 2.13-pre1
- Kernel, util-linux 2.13-pre2
- Kernel, util-linux 2.8 to 2.12q
- MandrakeSoft, Mandrake Linux 10.0 AMD64
- MandrakeSoft, Mandrake Linux 10.0
- MandrakeSoft, Mandrake Linux 10.1 X86_64
- MandrakeSoft, Mandrake Linux 10.1
- MandrakeSoft, Mandrake Linux LE2005 X86_64
- MandrakeSoft, Mandrake Linux LE2005
- MandrakeSoft, Mandrake Linux Corporate Server 2.1 X86_64
- MandrakeSoft, Mandrake Linux Corporate Server 2.1
- MandrakeSoft, Mandrake Linux Corporate Server 3.0 X86_64
- MandrakeSoft, Mandrake Linux Corporate Server 3.0
- MandrakeSoft, Mandrake Multi Network Firewall 2.0
- RedHat, Enterprise Linux 2.1 WS
- RedHat, Enterprise Linux 2.1 ES
- RedHat, Enterprise Linux 2.1 AS
- RedHat, Enterprise Linux 3 AS
- RedHat, Enterprise Linux 3 ES
- RedHat, Enterprise Linux 3 Desktop
- RedHat, Enterprise Linux 3 WS
- RedHat, Enterprise Linux 4 AS
- RedHat, Enterprise Linux 4 Desktop
- RedHat, Enterprise Linux 4 ES
- RedHat, Enterprise Linux 4 WS
- RedHat, Linux Advanced Workstation 2.1 Itanium
Remedy:
Upgrade to the latest version of util-linux (2.12r-pre1 or 2.13-pre3 or later), available from the Linux Kernel Archives FTP site. See References.
As a workaround, ensure the /tc/fstab is edited or delete the setuid bit from the umount.
For Debian GNU/Linux:
Refer to DSA-825-1 and DSA-823-1 for patch, upgrade, or suggested workaround information. See References.
For Red Hat Linux:
Refer to RHSA-2005:782-12 for patch, upgrade, or suggested workaround information. See References.
For Gentoo Linux:
Refer to Gentoo Linux Security Announcement GLSA 2005-09-15 for patch, upgrade, or suggested workaround information. See References.
For Ubuntu Linux:
Refer to USN-184-1 for patch, upgrade, or suggested workaround information. See References.
For other distributions:
Contact your vendor for upgrade or patch information.
Consequences:
Gain Privileges
References:
- BugTraq Mailing List, 2005-09-12 20:16:32, util-linux: unintentional grant of privileges by umount at http://marc.theaimsgroup.com/?l=bugtraq&m=112656096125857&w=2.
- The The Linux Kernel Archives Web site, Index of /pub/linux/utils/util-linux/testing at http://www.kernel.org/pub/linux/utils/util-linux/testing/.
- ASA-2006-014: util-linux and mount security update (RHSA-2005-782)
- BID-14816: Util-Linux UMount Remounting Filesystem Option Clearing Vulnerability
- BID-16280: Util-Linux Script Command Arbitrary File Overwrite Vulnerability
- CVE-2005-2876: umount in util-linux 2.8 to 2.12q, 2.13-pre1, and 2.13-pre2, and other packages such as loop-aes-utils, allows local users with unmount permissions to gain privileges via the -r (remount) option, which causes the file system to be remounted with just the read-only flag, which effectively clears the nosuid, nodev, and other flags.
- DSA-823: util-linux -- privilege escalation
- DSA-825: loop-aes-utils -- privilege escalation
- GLSA-200509-15: util-linux: umount command validation error
- MDKSA-2005:167: Updated util-linux packages fix umount vulnerability
- RHSA-2005-782: util-linux and mount security update
- SA16785: util-linux umount "-r" Re-Mounting Security Issue
- SA17133: Sun Java Desktop System umount "-r" Re-Mounting Security Issue
- SA18502: Avaya Products util-linux / mount Security Issue and Vulnerability
- SUSE-SR:2005:021: SUSE Security Summary Report
- USN-184-1: umount vulnerability
Reported:
Sep 12, 2005
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