Security Audit: Visible Lib Directories

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This is an advisory for TWiki site administrators to check their TWiki installation to make sure the lib directories are not visible over http.

Vulnerable Software Version

Any TWiki site with non-standard TWiki setup and Apache configuration might be vulnerable.

Impact if Exposed

The TWiki configuration file and TWiki source code might be viewable with a web browser, which exposes more details than necessary from a security point of view.

Details

If you followed the TWiki installation steps as described in TWikiInstallationGuide you should be OK. However, any non-standard TWiki installation should be checked carefully to see if the lib directory is not exposed by http. Directories twiki/data, twiki/lib, twiki/templates and all their subdirectories and the files they include should be configured in your Apache server so that they are not visible through URLs.

To check your site:

1. Test your site if /lib/TWiki.cfg is available via the web, by simply browsing to it.
   Hint: If you are curiuos as to where the lib directory is located, it is usually on the same directory level as the pub directory. Have a look at the images on your wiki to find out which one that is, as they are usually stored below the pub directory. Of course, the easiest way to find the correct URL is to look how the files are located on your server (and taking in account the instructions you set in httpd.conf - especially the Alias setting).
2. Test your site if lib/TWiki is exposed as a URL. Try a Google search on your site,
   http://www.google.com/search?q=allinurl:lib/TWiki+site:example.org
   (replace example.org with your site)

Countermeasures

Fix Alias and Directory settings in the Apache configuration file(s).

1. In the Apache configuration file(s) for TWiki pay special attention to the Alias, Directory[Match], Files[Match] and Location[Match] instructions.
2. Read the Apache documentation for release 1.3, 2.0 or 2.1 on the order these instructions are applied in.
3. Apply fixes.
4. Retest your site.

FIXME: More detailed instructions.

Authors and Credits

• Credit to Moritz Naumann (http://www.moritz-naumann.com/) for disclosing the issue to the twiki-security@listsPLEASENOSPAM.sourceforge.net mailing list
• TWiki:Main.CrawfordCurrie and TWiki:Main.PeterThoeny for investigating the issue and for creating the security audit

Action Plan with Timeline

-- PeterThoeny - 28 Sep 2005
-- Moritz Naumann - 28 Sep 2005

Discussions