full-disclosure - bzip2 bombs still causes problems in antivirus-software

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Message-ID: <31689056.1073673472@[10.3.62.6]>
From: pbieringer at aerasec.de (Dr. Peter Bieringer)
Subject: bzip2 bombs still causes problems in antivirus-software

Hi,

sure you remember the e-mail from Steve Wray in August 2003 about bzip2 
bombs and the possible DoS against antivirus-software:
http://lists.netsys.com/pipermail/full-disclosure/2003-August/009255.html

We found that this is still an issue, especially we found that one vendor 
detects bzip2 bombs by pattern (2 GB of zeros are detected, but not 2 GB of 
e.g. 0x31).

Also others will neither detect the bomb, nor stopping decompression, looks 
like they missing smart code for anomaly detection and/or proper limits and 
eat all existing disk space and CPU power instead of reporting a problem.

Namely we confirm this issue still exists on:

* kavscanner of
   Kaspersky AntiVirus for Linux 5.0.1.0 (probably all versions since 4.5)
* vscan of
   Trend Micro InterScan VirusWall 3.8 Build 1130
* uvscan of
   McAfee Virus Scan for Linux v4.16.0

Probably other versions and products are vulnerable, too.

Full advisory is available here:

http://www.aerasec.de/security/advisories/txt/bzip2bomb-antivirusengines.txt

Hope this helps to bring this issue up again on software vendors to 
implement more smarter anomaly detection code and configurable limits 
(number of files, max size) in the decompression unit.

Regards,
	Dr. Peter Bieringer
-- 
Dr. Peter Bieringer                             Phone: +49-8102-895190
AERAsec Network Services and Security GmbH        Fax: +49-8102-895199
Wagenberger Stra?e 1                           Mobile: +49-174-9015046
D-85662 Hohenbrunn                       E-Mail: pbieringer@...asec.de
Germany                                Internet: http://www.aerasec.de