Gentoo: cmd5checkpw Local password leak vulnerability
Posted by Benjamin D. Thomas   
Gentoo cmd5checkpw contains a flaw allowing local users to access other users cmd5checkpw passwords.
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Gentoo Linux Security Advisory                           GLSA 200502-30
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                                            http://security.gentoo.org/
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  Severity: Low
     Title: cmd5checkpw: Local password leak vulnerability
      Date: February 25, 2005
      Bugs: #78256
        ID: 200502-30

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Synopsis
========

cmd5checkpw contains a flaw allowing local users to access other users
cmd5checkpw passwords.

Background
==========

cmd5checkpw is a checkpassword compatible authentication program that
uses CRAM-MD5 authentication mode.

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

    -------------------------------------------------------------------
     Package               /  Vulnerable  /                 Unaffected
    -------------------------------------------------------------------
  1  net-mail/cmd5checkpw     <= 0.22-r1                    >= 0.22-r2

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

Florian Westphal discovered that cmd5checkpw is installed setuid
cmd5checkpw but does not drop privileges before calling execvp(), so
the invoked program retains the cmd5checkpw euid.

Impact
======

Local users that know at least one valid /etc/poppasswd user/password
combination can read the /etc/poppasswd file.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All cmd5checkpw users should upgrade to the latest available version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=net-mail/cmd5checkpw-0.22-r2"

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

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

  http://security.gentoo.org/glsa/glsa-200502-30.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