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Decompression Bombs



As a followup to http://www.securityfocus.com/bid/9393/, where we pointed out vulnerabilities of some antivirus-gateways while decompressing bzip2-bombs, we were interested in the behaviour of various applications that process compressed data.

It looks as if not only bzip2 bombs, but also decompression bombs in general might cause problems. Compression is used in many applications, but hardly any maximum size limits are checked during the decompression of untrusted content.

We've created several bombs (bzip2, gzip, zip, mime-embedded bombs, png and gif graphics, openoffice zip bombs). With these we tested some more applications like additional antivirus engines, various web browsers, openoffice.org, and the Gimp.

As a result, much more applications as we thought crashed. The manufacturers of software should care more about the processing of untrusted input.

For details see our full advisory, written by Dr. Peter Bieringer: http://www.aerasec.de/security/advisories/decompression-bomb-vulnerability.html

Best regards,
Dr. Matthias Leu
--
AERAsec Network Services and Security GmbH
Wagenberger Strasse 1
D-85662 Hohenbrunn, Germany
http://www.aerasec.de