Gentoo: lm_sensors Insecure temporary file creation
Posted by Benjamin D. Thomas   
Gentoo lm_sensors is vulnerable to linking attacks, potentially allowing a local user to overwrite arbitrary files.
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Gentoo Linux Security Advisory                           GLSA 200508-19
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: lm_sensors: Insecure temporary file creation
      Date: August 30, 2005
      Bugs: #103568
        ID: 200508-19

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Synopsis
========

lm_sensors is vulnerable to linking attacks, potentially allowing a
local user to overwrite arbitrary files.

Background
==========

lm_sensors is a software package that provides drivers for monitoring
the temperatures, voltages, and fans of Linux systems with hardware
monitoring devices.

Affected packages
=================

    -------------------------------------------------------------------
     Package              /  Vulnerable  /                  Unaffected
    -------------------------------------------------------------------
  1  sys-apps/lm_sensors     < 2.9.1-r1                    >= 2.9.1-r1

Description
===========

Javier Fernandez-Sanguino Pena has discovered that lm_sensors
insecurely creates temporary files with predictable filenames when
saving configurations.

Impact
======

A local attacker could create symbolic links in the temporary file
directory, pointing to a valid file somewhere on the filesystem. When
the pwmconfig script of lm_sensors is executed, this would result in
the file being overwritten with the rights of the user running the
script, which typically is the root user.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All lm_sensors users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=sys-apps/lm_sensors-2.9.1-r1"

References
==========

  [ 1 ] CAN-2005-2672
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-2672

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

  http://security.gentoo.org/glsa/glsa-200508-19.xml

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
http://bugs.gentoo.org.

License
=======

Copyright 2005 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/2.0