Gentoo: Webmin, Usermin Format string vulnerability
Posted by Benjamin D. Thomas   
Gentoo Webmin and Usermin are vulnerable to a format string vulnerability which may lead to the execution of arbitrary code.
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Gentoo Linux Security Advisory                           GLSA 200512-02
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                                            http://security.gentoo.org/
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  Severity: High
     Title: Webmin, Usermin: Format string vulnerability
      Date: December 07, 2005
      Bugs: #113888
        ID: 200512-02

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Synopsis
========

Webmin and Usermin are vulnerable to a format string vulnerability
which may lead to the execution of arbitrary code.

Background
==========

Webmin is a web-based interface for Unix-like systems. Usermin is a
simplified version of Webmin designed for use by normal users rather
than system administrators.

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

    -------------------------------------------------------------------
     Package            /  Vulnerable  /                    Unaffected
    -------------------------------------------------------------------
  1  app-admin/webmin        < 1.250                          >= 1.250
  2  app-admin/usermin       < 1.180                          >= 1.180
    -------------------------------------------------------------------
     2 affected packages on all of their supported architectures.
    -------------------------------------------------------------------

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

Jack Louis discovered that the Webmin and Usermin "miniserv.pl" web
server component is vulnerable to a Perl format string vulnerability.
Login with the supplied username is logged via the Perl "syslog"
facility in an unsafe manner.

Impact
======

A remote attacker can trigger this vulnerability via a specially
crafted username containing format string data. This can be exploited
to consume a large amount of CPU and memory resources on a vulnerable
system, and possibly to execute arbitrary code of the attacker's choice
with the permissions of the user running Webmin.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Webmin users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=app-admin/webmin-1.250"

All Usermin users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=app-admin/usermin-1.180"

References
==========

  [ 1 ] CVE-2005-3912
        http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-3912
  [ 2 ] Dyad Security Advisory
        http://www.dyadsecurity.com/webmin-0001.html

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

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

  http://security.gentoo.org/glsa/glsa-200512-02.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