pam_ldap: Authentication bypass vulnerability

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200612-19 / pam_ldap
Release Date	December 20, 2006
Latest Revision	December 20, 2006: 01
Impact	low
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
sys-auth/pam_ldap	< 183	>= 183	All supported architectures

Related bugreports: #153916

Synopsis

pam_ldap contains a vulnerability that may allow a remote user with a locked account to gain unauthorized system access.

2. Impact Information

Background

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

Description

Steve Rigler discovered that pam_ldap does not correctly handle "PasswordPolicyResponse" control responses from an LDAP directory. This causes the pam_authenticate() function to always succeed, even if the previous authentication failed.

Impact

A locked user may exploit this vulnerability to bypass the LDAP authentication mechanism, possibly gaining unauthorized access to the system.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All pam_ldap users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-auth/pam_ldap-183"

4. References

CVE-2006-5170

Page updated December 20, 2006

Summary: This is a Gentoo Linux Security Advisory

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