Gentoo: pam_ldap and nss_ldap Plain text authentication
Posted by Benjamin D. Thomas   
Gentoo pam_ldap and nss_ldap fail to restart TLS when following a referral, possibly leading to credentials being sent in plain text.
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Gentoo Linux Security Advisory                           GLSA 200507-13
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: pam_ldap and nss_ldap: Plain text authentication leak
      Date: July 14, 2005
      Bugs: #96767
        ID: 200507-13

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Synopsis
========

pam_ldap and nss_ldap fail to restart TLS when following a referral,
possibly leading to credentials being sent in plain text.

Background
==========

pam_ldap is a Pluggable Authentication Module which allows
authentication against an LDAP directory. nss_ldap is a Name Service
Switch module which allows 'passwd', 'group' and 'host' database
information to be pulled from LDAP. TLS is Transport Layer Security, a
protocol that allows encryption of network communications.

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

    -------------------------------------------------------------------
     Package            /  Vulnerable  /                    Unaffected
    -------------------------------------------------------------------
  1  sys-auth/nss_ldap      < 239-r1                         >= 239-r1
                                                            *>= 226-r1
  2  sys-auth/pam_ldap      < 178-r1                         >= 178-r1
    -------------------------------------------------------------------
     2 affected packages on all of their supported architectures.
    -------------------------------------------------------------------

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

Rob Holland of the Gentoo Security Audit Team discovered that pam_ldap
and nss_ldap fail to use TLS for referred connections if they are
referred to a master after connecting to a slave, regardless of the
"ssl start_tls" ldap.conf setting.

Impact
======

An attacker could sniff passwords or other sensitive information as the
communication is not encrypted.

Workaround
==========

pam_ldap and nss_ldap can be set to force the use of SSL instead of
TLS.

Resolution
==========

All pam_ldap users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=sys-auth/pam_ldap-178-r1"

All nss_ldap users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose sys-auth/nss_ldap

References
==========

  [ 1 ] CAN-2005-2069
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-2069

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

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

  http://security.gentoo.org/glsa/glsa-200507-13.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