Chamilo 1.8.7 / Dokeos 1.8.6 Remote File Disclosure

[beford <xbefordx@xxxxxxxxx>]

Affected products
=================
Dokeos 1.8.6.1 / 2.0
Chamilo 1.8.7.1


Resume
======
Two file disclosure flaws exists on these LMS platforms, which could
allow an attacker registered on the system to obtain files from the
server, i.e your database configuration file, or any other file
readeable by the webserver.

Details
=======
1) The user input to the $_GET['file'] variable was not been cleaned
at all, and used to open a file and send it to the browser of the
user, it only required to be registered and subscribed to a course:

POC:

http://lmscampus.tld/main/gradebook/open_document.php?file=../main/inc/conf/configuration.php


2) The user input on $_GET['doc_url'] was been checked for transversal
path injection attempts, however the filter is wrongly implemented,
and can be bypassed. Also other functions that should prevent this
behavior were not working properly.

When passing "..././" to the filter it replaces "../" first with "", that
leaves me with "../" which allows me to bypass it completly.


http://lmscampus.tld/main/document/download.php?doc_url=/..././..././..././main/inc/conf/configuration.php


Vendor notified: Jan 29/31, 2011
Vendor response Dokeos: none
Vendor response Chamilo: Patches developed and new version expected
around Feb 15