Gentoo: pam_ldap Authentication bypass vulnerability
Posted by Benjamin D. Thomas   
Gentoo pam_ldap contains a vulnerability that may allow a remote attacker to gain system access.
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Gentoo Linux Security Advisory                           GLSA 200508-22
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: pam_ldap: Authentication bypass vulnerability
      Date: August 31, 2005
      Bugs: #103659
        ID: 200508-22

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Synopsis
========

pam_ldap contains a vulnerability that may allow a remote attacker to
gain system access.

Background
==========

pam_ldap is a Pluggable Authentication Module which allows
authentication against LDAP directories.

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

    -------------------------------------------------------------------
     Package            /  Vulnerable  /                    Unaffected
    -------------------------------------------------------------------
  1  sys-auth/pam_ldap        < 180                             >= 180

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

When a pam_ldap client attempts to authenticate against an LDAP server
that omits the optional error value from the
PasswordPolicyResponseValue, the authentication attempt will always
succeed.

Impact
======

A remote attacker may exploit this vulnerability to bypass the LDAP
authentication mechanism, gaining access to the system possibly with
elevated privileges.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All pam_ldap users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=sys-auth/pam_ldap-180"

References
==========

  [ 1 ] CAN-2005-2641
        http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-2641
  [ 2 ] US-CERT VU#778916
        http://www.kb.cert.org/vuls/id/778916

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

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

  http://security.gentoo.org/glsa/glsa-200508-22.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