----- Original Message ----- From: "Dr. Peter Bieringer"
To: ; Sent: Friday, January 09, 2004 9:37 AM 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.ht ml 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 126.96.36.199 (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-antivirusengi nes.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 Straße 1 Mobile: +49-174-9015046 D-85662 Hohenbrunn E-Mail: email@example.com Germany Internet: http://www.aerasec.de