Gentoo: Rootkit Hunter Insecure temporary file creation
Posted by Benjamin D. Thomas   
Gentoo Rootkit Hunter is vulnerable to symlink attacks, potentially allowing a local user to overwrite arbitrary files.
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Gentoo Linux Security Advisory                           GLSA 200504-25
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: Rootkit Hunter: Insecure temporary file creation
      Date: April 26, 2005
      Bugs: #90007
        ID: 200504-25

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Synopsis
========

Rootkit Hunter is vulnerable to symlink attacks, potentially allowing a
local user to overwrite arbitrary files.

Background
==========

Rootkit Hunter is a scanning tool to detect rootkits, backdoors and
local exploits on a local machine. Rootkit Hunter uses downloaded data
files to check file integrity. These files are updated via the
check_update.sh script.

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

    -------------------------------------------------------------------
     Package                 /  Vulnerable  /               Unaffected
    -------------------------------------------------------------------
  1  app-forensics/rkhunter     < 1.2.3-r1                 >= 1.2.3-r1

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

Sune Kloppenborg Jeppesen and Tavis Ormandy of the Gentoo Linux
Security Team have reported that the check_update.sh script and the
main rkhunter script insecurely creates several temporary files with
predictable filenames.

Impact
======

A local attacker could create symbolic links in the temporary files
directory, pointing to a valid file somewhere on the filesystem. When
rkhunter or the check_update.sh script runs, this would result in the
file being overwritten with the rights of the user running the utility,
which could be the root user.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Rootkit Hunter users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=app-forensics/rkhunter-1.2.3-r1"

References
==========

  [ 1 ] CAN-2005-1270
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1270

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

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

  http://security.gentoo.org/glsa/glsa-200504-25.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