[VulnWatch] Digital Armaments: Apache auth_ldap module Multiple Format Strings Vulnerability

["Digital Armaments" <vulnwatch@xxxxxxxxxxxxxxxxxxxx>]

Apache auth_ldap module Multiple Format Strings Vulnerability

http://www.digitalarmaments.com/2006090173928420.html

I. Background

auth_ldap is an LDAP authentication module for Apache, the world's most
popular web server. auth_ldap has excellent performance, and supports
Apache on both Unix and Windows NT. It also has support for LDAP over SSL,
and a mode that lets Microsoft Frontpage clients manage their web
permissions while still using LDAP for authentication.
For further information or detail about the software you can refer to the
vendor's homepage:

http://www.rudedog.org/auth_ldap/

II. Problem Description

Due to an insecure usage of the function apache logging function
(ap_log_rerror) in auth_ldap_log_reason function it's possible to run
arbitrary code on the server running the module. For example this can
generate a custom format string that can be supplied by the attacker
through the username given during the apache authentication process but
several parts of the module are affected.

III. Detection

This problem has been detected on latest version of auth_ldap 1.6.0 and on
prior version from 1.2.x. It persists on all platforms where auth_ldap can
be compiled.

IV. Impact analisys

Successful exploitation allows an attacker to gain access to the system.
Exploit code is required.

V. Solution

First notification 12.22.2005.
Second notification 01.09.2006.
The vendor answered second notification.
A new patched version is available.

VI. Credit

Seregorn - seregon@xxxxxxxxxxxxx is credited with this discovery.

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VII. Legal Notices

Copyright © 2006 Digital Armaments LLC.

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