DansGuarding File Extension Filter Can Be Bypassed With Hex-Encoded URLs
SecurityTracker Alert ID: 1010817|
SecurityTracker URL: http://securitytracker.com/id/1010817
(Links to External Site)
Date: Jul 30 2004
Host/resource access via network|
Fix Available: Yes Vendor Confirmed: Yes Exploit Included: Yes |
Version(s): 2.8 and prior versions|
A vulnerability was reported in DansGuardian. A remote user can create a URL that will bypass the file extension filtering.|
Ruben Molina reported that a remote user can create a URL that contains a hex-encoded character to bypass the file extension filter.
Some demonstration exploit URLs are provided:
The vendor was reportedly notified on July 28, 2004.
A remote user can bypass filtering rules to access a file with a banned file extension.|
The vendor has released a fixed version (220.127.116.11), available at:|
Vendor URL: dansguardian.org/ (Links to External Site)
Input validation error, State error|
|Underlying OS: Linux (Any), UNIX (Any)|
Source Message Contents
Subject: DansGuardian Hex Encoding URL Banned Extension Filter Bypass|
DansGuardian Hex Encoding URL Banned Extension Filter Bypass Vulnerability
Original Release Date: 2004-07-29
Author: Ruben Molina (a.k.a fradiavolo)
!!! VIVA COLOMBIA !!!
1. Systems affected:
All DansGuardian up to and including DansGuardian 2.8.
DansGuardian (http://dansguardian.org) is a web Open Source content filter
for various Unix based operating systems, including Linux. It filters the
content of pages based on many methods including phrase matching, PICS
DansGuardian may allow malicious users to bypass the extension filter
processing URLs which contain an hex encoded filename (e.g:
http://server/file.%65%78%65 or http://server/file%2eexe).
Under some installations, this may violate security policy, or allow users to
inadvertantly access malicious web content.
Upgrade to DansGuardian 18.104.22.168
--- FOptionContainer.cpp.diff ---
6. Timeline and credits:
28/07/2004 Notification to the main developer (author at dansguardian dot
28/07/2004 DansGuardian 22.214.171.124 released
29/07/2004 Public Security Advisory.
7. Thanks to:
Gigax.org people and Silence Team ;)
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