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Gentoo 201612-02: DavFS2 Local Privilege Escalation Advisory

gentoo
Calendar Grey December 2, 2016
Dist Gentoo Esm H88
The Gentoo Security Advisory GLSA-202303-01 outlines a vulnerability in OpenSSH, which allows local attackers to gain unauthorized access to sensitive information.
A vulnerability in DavFS2 allows local users to gain root privileges.

Summary

DavFS2 installs "/usr/sbin/mount.davfs" as setuid root. This utility uses "system()" to call "/sbin/modprobe". While the call to "modprobe" itself cannot be manipulated, a local authenticated user can set the "MODPROBE_OPTIONS" environment variable to pass a user controlled path, allowing the loading of an arbitrary kernel module.

Topics%20covered

Topics Covered

security advisory gentoo local privilege escalation normal severity davfs2

Resolution

All DavFS2 users should upgrade to the latest version: # emerge --sync # emerge --ask --oneshot --verbose ">=net-fs/davfs2-1.5.2"

References

[ 1 ] CVE-2013-4362 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2013-4362

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: https://security.gentoo.org/glsa/201612-02
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Concerns

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users' machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.

Severity: Normal
Title: DavFS2: Local privilege escalation
Date: December 02, 2016
Bugs: #485232
ID: 201612-02

Topics%20covered

Topics Covered

security advisory gentoo local privilege escalation normal severity davfs2

Synopsis

A vulnerability in DavFS2 allows local users to gain root privileges.

Background

DavFS2 is a file system driver that allows you to mount a WebDAV server as a local disk drive.

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Affected Packages

------------------------------------------------------------------- Package / Vulnerable / Unaffected ------------------------------------------------------------------- 1 net-fs/davfs2 < 1.5.2 >= 1.5.2

Impact

===== A local user could gain root privileges.

Workaround

The system administrator should ensure that all modules the "mount.davfs" utility tries to load are loaded upon system boot before any local user can call the utility. An additional defense measure can be implemented by enabling the Linux kernel module signing feature. This assists in the prevention of arbitrary modules being loaded.

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