Digital Armaments Security Advisory 01.09.2006: Apache auth_ldap module Multiple Format Strings Vulnerability
Digital Armaments advisory is 12.22.2005
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 many 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 abitrary
code on the server running the module. For example this can generate a custom
format string that can be supplied by the attacker throught 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 persist on all platforms where auth_ldap can be
compiled.
IV. Impact analisys
Successful exploitation allow 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 will be available.
VI. Credit
Seregorn - seregon@xxxxxxxxxxxxx is credited with this discovery.
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