[ GLSA 200710-25 ] MLDonkey: Privilege escalation

[Raphael Marichez <falco () gentoo org>]

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Gentoo Linux Security Advisory                           GLSA 200710-25
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                                            http://security.gentoo.org/
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  Severity: High
     Title: MLDonkey: Privilege escalation
      Date: October 24, 2007
      Bugs: #189412
        ID: 200710-25

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Synopsis
========

The Gentoo MLDonkey ebuild adds a user to the system with a valid login
shell and no password.

Background
==========

MLDonkey is a peer-to-peer filesharing client that connects to several
different peer-to-peer networks, including Overnet and BitTorrent.

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

    -------------------------------------------------------------------
     Package           /  Vulnerable  /                     Unaffected
    -------------------------------------------------------------------
  1  net-p2p/mldonkey     < 2.9.0-r3                       >= 2.9.0-r3

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

The Gentoo MLDonkey ebuild adds a user to the system named "p2p" so
that the MLDonkey service can run under a user with low privileges.
This user is created with a valid login shell and no password.

Impact
======

A remote attacker could log into a vulnerable system as the p2p user.
This would require an installed login service that permitted empty
passwords, such as SSH configured with the "PermitEmptyPasswords yes"
option, a local login console, or a telnet server.

Workaround
==========

See Resolution.

Resolution
==========

Change the p2p user's shell to disallow login. For example, as root run
the following command:

    # usermod -s /bin/false p2p

NOTE: updating to the current MLDonkey ebuild will not remove this
vulnerability, it must be fixed manually. The updated ebuild is to
prevent this problem from occurring in the future.

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

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

  http://security.gentoo.org/glsa/glsa-200710-25.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 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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