- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Gentoo Linux Security Advisory GLSA 201612-02 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - https://security.gentoo.org/ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Severity: Normal Title: DavFS2: Local privilege escalation Date: December 02, 2016 Bugs: #485232 ID: 201612-02 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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. Affected packages ================= ------------------------------------------------------------------- Package / Vulnerable / Unaffected ------------------------------------------------------------------- 1 net-fs/davfs2 < 1.5.2 >= 1.5.2 Description =========== 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. 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. 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 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. License ======= Copyright 2016 Gentoo Foundation, Inc; referenced text belongs to its owner(s). The contents of this document are licensed under the Creative Commons - Attribution / Share Alike license. http://creativecommons.org/licenses/by-sa/2.5