[ GLSA 200704-11 ] Vixie Cron: Denial of Service

[Matthias Geerdsen <vorlon () gentoo org>]

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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

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