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Gentoo Linux Security Advisory                           GLSA 200704-11
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                                            http://security.gentoo.org/
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  Severity: Low
     Title: Vixie Cron: Denial of Service
      Date: April 16, 2007
      Bugs: #164466
        ID: 200704-11

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Synopsis
========

The Gentoo implementation of Vixie Cron is vulnerable to a local Denial
of Service.

Background
==========

Vixie Cron is a command scheduler with extended syntax over cron.

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

    -------------------------------------------------------------------
     Package                 /  Vulnerable  /               Unaffected
    -------------------------------------------------------------------
  1  sys-process/vixie-cron      < 4.1-r10                  >= 4.1-r10

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

During an internal audit, Raphael Marichez of the Gentoo Linux Security
Team found that Vixie Cron has weak permissions set on Gentoo, allowing
for a local user to create hard links to system and users cron files,
while a st_nlink check in database.c will generate a superfluous error.

Impact
======

Depending on the partitioning scheme and the "cron" group membership, a
malicious local user can create hard links to system or users cron
files that will trigger the st_link safety check and prevent the
targeted cron file from being run from the next restart or database
reload.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Vixie Cron users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=sys-process/vixie-cron-4.1-r10"

References
==========

  [ 1 ] CVE-2007-1856
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-1856

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

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

  http://security.gentoo.org/glsa/glsa-200704-11.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 2007 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