DansGuardian Hex Encoding URL Banned Extension Filter Bypass Vulnerability ========================================================================== Original Release Date: 2004-07-29 Author: Ruben Molina (a.k.a fradiavolo) Email: ruben@xxxxxxxxxxx !!! VIVA COLOMBIA !!! 1. Systems affected: All DansGuardian up to and including DansGuardian 2.8. 2. Overview: DansGuardian (http://dansguardian.org) is a web Open Source content filter available for various Unix based operating systems, including Linux. It filters the actual content of pages based on many methods including phrase matching, PICS filtering and URL filtering. DansGuardian may allow malicious users to bypass the extension filter rules when processing URLs which contain an hex encoded filename (e.g: http://server/file.%65%78%65 or http://server/file%2eexe). 3. Impact: Under some installations, this may violate security policy, or allow users to inadvertantly access malicious web content. 4. Solution: Upgrade to DansGuardian 2.8.0.1 5. Patch: --- FOptionContainer.cpp.diff --- 806d805 < url.hexDecode(); --------------------------------- 6. Timeline and credits: 28/07/2004 Notification to the main developer (author at dansguardian dot org) 28/07/2004 DansGuardian 2.8.0.1 released 29/07/2004 Public Security Advisory. 7. Thanks to: Gigax.org people and Silence Team ;) -- Rubén Molina 0xDEF3F700 Zure atera iristean ostikada jotzen nola irtengo zara? Eskuak buru gainean ala pistolaren gatilvan?
