AusCERT - ESB-2008.0878 -- [Win][UNIX/Linux] -- TWiki command execution vulnerability

HOME
About AusCERT
Membership
PKI Services
Training
Publications
Sec. Bulletins
Conferences
News & Media
Services
Web Log
Site Map
Site Help
Member login
ESB-2008.0878 -- [Win][UNIX/Linux] -- TWiki command execution vulnerability
Date: 19 September 2008
References: ESB-2008.0895

Click here for printable version
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

===========================================================================
             AUSCERT External Security Bulletin Redistribution

                    ESB-2008.0878 -- [Win][UNIX/Linux]
                   TWiki command execution vulnerability
                             19 September 2008

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:              TWiki
Publisher:            US-CERT
Operating System:     UNIX variants (UNIX, Linux, OSX)
                      Windows
Impact:               Read-only Data Access
Access:               Remote/Unauthenticated
CVE Names:            CVE-2008-4112

Original Bulletin:    http://www.kb.cert.org/vuls/id/362012

Revision History:     September 19 2008: Added CVE Reference
                      September 16 2008: Initial Release

- --------------------------BEGIN INCLUDED TEXT--------------------

Vulnerability Note VU#362012

TWiki command execution vulnerability

Overview

The TWiki wiki software fails to validate input passed to certain URLs. By 
accessing a URL containing the TWiki configuration script, an attacker may 
be able to read arbitrary files.

I. Description

TWiki is a wiki that is runs in the context of the Apache web server. TWiki 
is installed by configuring Apache, then accessing a configuration script 
from a web browser. Before executing the configuration script, the TWiki 
installation instructions provide a generator for Apache configuration 
directives that is designed to prevent unauthorized access to the script.

There is a command execution vulnerability in TWiki versions prior to 4.2.3.
According to the TWiki download page, this issue can only be exploited if 
the configure script was not secured as described in step number 8 in the 
installation guide.

Public exploit code has been released that targets this vulnerability. 
TWiki servers typically use predictable URLs and vulnerable systems may be 
found by querying search engines.

II. Impact

A remote attacker may be able to view arbitrary configuration files on a 
vulnerable system.

III. Solution

TWiki versions 4.2.0 and higher

The TWiki team has provided a configuration script to address this issue. 
The script is available here:
  http://twiki.org/p/pub/Codev/TWikiRelease04x02x03/configure

TWiki versions prior to 4.2.0

Refer to step 8 in the Twiki installation guide.

Make the configure script not executable

Removing, renaming or marking the TWiki configure script 
(twiki/bin/configure) as not executable will prevent this vulnerability 
from being exploited.

Restrict access

Restricting access by using a web application or string-matching firewall 
to block URLs that contain the string /bin/configure may partially mitigate 
this vulnerability. This workaround is unlikely to be effective in many 
cases, such as when the server uses the https protocol.

Systems Affected
Vendor	Status	        Date Updated
TWiki	Vulnerable	12-Sep-2008

References

http://twiki.org/cgi-bin/view/TWiki/TWikiInstallationGuide#8
http://twiki.org/cgi-bin/view/TWiki.ApacheConfigGenerator
http://twiki.org/p/pub/Codev/TWikiRelease04x02x03/configure
http://www.milw0rm.com/exploits/6269

Credit

Thanks to the TWiki team for information that was used in this report.

This document was written by Ryan Giobbi.
Other Information
Date Public	        12/09/2008
Date First Published	12/09/2008 15:00:10
Date Last Updated	12/09/2008
CERT Advisory	 
CVE-ID(s)	 
NVD-ID(s)	 
US-CERT Technical Alerts	 
Metric	                38.25
Document Revision	6

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

        http://www.auscert.org.au/render.html?cid=1980

If you believe that your computer system has been compromised or attacked in 
any way, we encourage you to let us know by completing the secure National IT 
Incident Reporting Form at:

        http://www.auscert.org.au/render.html?it=3192

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
===========================================================================

-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967

iQCVAwUBSNL9/ih9+71yA2DNAQKZ1gP+OOZHdFN3tdezQMhV/jBCcmD0LNzQ8mdb
8sJl0DZEZhIuEJMT+8Pa04z8CiJ/WJr7nSRilVBCgYlHpk0fsWaGqtinteeOroUs
2sIW7ZWuNpAJ0CfqPH1Ktz8rDOE6H4DFdsGuO/Btvjv9WTFgGZgY4kwck93x4Nrv
r6b3cpO3LFQ=
=3Z2k
-----END PGP SIGNATURE-----