Bug 841940 (CVE-2012-3409) - CVE-2012-3409 ecryptfs-utils: suid helper does not restrict mounting filesystems with nosuid,nodev leading to possible privilege escalation
Summary: CVE-2012-3409 ecryptfs-utils: suid helper does not restrict mounting filesyst...
Status: CLOSED ERRATA
Alias: CVE-2012-3409
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
(Show other bugs)
Version: unspecified
Hardware: All Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard: impact=moderate,public=20120710,repor...
Keywords: Security
Depends On: 842512
Blocks: 841942
TreeView+ depends on / blocked
 
Reported: 2012-07-20 15:25 UTC by Vincent Danen
Modified: 2012-08-03 11:28 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Environment:
Last Closed: 2012-07-24 04:54:33 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


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Description Vincent Danen 2012-07-20 15:25:56 UTC
It was reported [1] that the private ecryptfs mount helper (/sbin/mount.ecryptfs_private), which is setuid-root, could allow an unprivileged local user to mount user-controlled ecryptfs shares on the local system.  Because the ecryptfs helper does not mount filesystems with the "nosuid" and "nodev" flags, it would be possible for a user to mount a filesystem containing setuid-root binaries and/or device files that could lead to the escalation of their privileges.  This could be done via a USB device, if the user had physical access to the system.

It was however also noted [2] that this may only affect version 86 and later, as the encrypted home source and destination mount points were hard-coded up until that version.

Forcing MS_NOSUID and MS_NODEV mount flags was added to version 99 (commits [3],[4])


[1] http://www.openwall.com/lists/oss-security/2012/07/10/19
[2] http://www.openwall.com/lists/oss-security/2012/07/11/2
[3] http://bazaar.launchpad.net/~ecryptfs/ecryptfs/trunk/revision/705
[4] http://bazaar.launchpad.net/~ecryptfs/ecryptfs/trunk/revision/708

Comment 1 Vincent Danen 2012-07-20 15:30:39 UTC
I also forgot to note that on Fedora and RHEL, you need to be part of the ecryptfs group to even use the ecryptfs filesystems/utilities, which lowers the attack surface considerably.

Comment 3 Huzaifa S. Sidhpurwala 2012-07-24 04:53:07 UTC
Statement:

Not Vulnerable. This issue does not affect the version of ecryptfs-utils as shipped with Red Hat Enterprise Linux 5 and 6.

Comment 4 Huzaifa S. Sidhpurwala 2012-07-24 04:53:57 UTC
Created ecryptfs-utils tracking bugs for this issue

Affects: fedora-all [bug 842512]

Comment 5 Fedora Update System 2012-08-03 11:27:42 UTC
ecryptfs-utils-99-1.fc17 has been pushed to the Fedora 17 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 6 Fedora Update System 2012-08-03 11:28:20 UTC
ecryptfs-utils-99-1.fc16 has been pushed to the Fedora 16 stable repository.  If problems still persist, please make note of it in this bug report.


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