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bzip2 -- denial of service and permission race vulnerabilities

Description:

Problem Description

Two problems have been discovered relating to the extraction of bzip2-compressed files. First, a carefully constructed invalid bzip2 archive can cause bzip2 to enter an infinite loop. Second, when creating a new file, bzip2 closes the file before setting its permissions.

Impact

The first problem can cause bzip2 to extract a bzip2 archive to an infinitely large file. If bzip2 is used in automated processing of untrusted files this could be exploited by an attacker to create an denial-of-service situation by exhausting disk space or by consuming all available cpu time.

The second problem can allow a local attacker to change the permissions of local files owned by the user executing bzip2 providing that they have write access to the directory in which the file is being extracted.

Workaround

Do not uncompress bzip2 archives from untrusted sources and do not uncompress files in directories where untrusted users have write access.

References:

Affects:

portaudit: bzip2 -- denial of service and permission race vulnerabilities

Disclaimer: The data contained on this page is derived from the VuXML document, please refer to the the original document for copyright information. The author of portaudit makes no claim of authorship or ownership of any of the information contained herein.

If you have found a vulnerability in a FreeBSD port not listed in the database, please contact the FreeBSD Security Officer. Refer to "FreeBSD Security Information" for more information.


Oliver Eikemeier <eik@FreeBSD.org>