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

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.

Redistribution of this alert electronically is allowed. It should not be
edited in any way. Reprint the whole is allowed, partial reprint is not
permitted. For any other request please email
customerservice@xxxxxxxxxxxxxxxxxxxx for permission. Disclaimer: The
information in the advisory is believed to be accurate at the time of
publishing based on currently available information. Use of the
information constitutes acceptance for use in an AS IS condition. There
are no warranties with regard to this information. Neither the author nor
the publisher accepts any liability for any direct, indirect, or
consequential loss or damage arising from use of, or reliance on, this
information.

Relevant Pages

  • Re: LDAP Authentication from Linux
    ... doesn't the LDAP module in Apache require a secure connection on most recent Linux systems? ... Moving the ldap45457 user into the same OU as the rest of my normal users, and then changing apache to the below, and also adding "List Contents" Read permissions to that OU, as per what I read here for anonymous access. ... user marsh authentication failed; ...
    (microsoft.public.windows.server.sbs)
  • Re: Use Windows 2000 User Authentication for Apache
    ... auth_ldap works perfectly with apache and win2000. ... With ldap, no problem at all. ... stores the queried credentials in a cache and accelerates the whole authentication ... >> worth a try), Win2K Domain Controllers run an LDAP server, Apache may be ...
    (comp.os.linux.security)
  • Re: LDAP Authentication from Linux
    ... Moving the ldap45457 user into the same OU as the rest of my normal users, and then changing apache to the below, and also adding "List Contents" Read permissions to that OU, as per what I read here for anonymous access. ... user marsh authentication failed; ... Depending how you have LDAP set up, remember that the user you configure must have privileges to query AD. ... and if I bind using a Domain Admin account then all is well and I can login. ...
    (microsoft.public.windows.server.sbs)
  • A night with threads and gdb
    ... I was struggling in the effort to get apache ... searching for users in the ldap database. ... Later on I realized that sendmail wasn't using authentication, ... I guess that when started up without -X, one process dies and the ...
    (freebsd-questions)
  • Re: Disabling sslv2 on linux for port 636.
    ... Rohit khaladkar wrote: ... Showing this has nothing at all to do with apache. ... Is this server an LDAP server, ... If none of the above is true, then you need to shut down the LDAP ...
    (RedHat)