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: 2 Date: Wed, 29 Jun 2005 21:55:00 GMT From: FreeBSD Security Advisories <security-advisories@freebsd.org> Subject: FreeBSD Security Advisory FreeBSD-SA-05:14.bzip2 To: FreeBSD Security Advisories <security-advisories@freebsd.org> Message-ID: <200506292155.j5TLt0cj008194@freefall.freebsd.org> ============================================================================= FreeBSD-SA-05:14.bzip2 Security Advisory The FreeBSD Project Topic: bzip2 denial of service and permission race vulnerabilities Category: contrib Module: contrib_bzip2 Announced: 2005-06-29 Credits: Imran Ghory, Chris Evans Affects: All FreeBSD releases Corrected: 2005-06-29 21:38:48 UTC (RELENG_5, 5.4-STABLE) 2005-06-29 21:41:03 UTC (RELENG_5_4, 5.4-RELEASE-p3) 2005-06-29 21:42:33 UTC (RELENG_5_3, 5.3-RELEASE-p17) 2005-06-29 21:43:42 UTC (RELENG_4, 4.11-STABLE) 2005-06-29 21:45:14 UTC (RELENG_4_11, 4.11-RELEASE-p11) 2005-06-29 21:46:15 UTC (RELENG_4_10, 4.10-RELEASE-p16) CVE Name: CAN-2005-0953, CAN-2005-1260 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://www.freebsd.org/security/>. I. Background bzip2 is a block-sorting file compression utility. II. 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. III. 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. IV. Workaround Do not uncompress bzip2 archives from untrusted sources and do not uncompress files in directories where untrusted users have write access. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 4-STABLE or 5-STABLE, or to the RELENG_5_4, RELENG_5_3, RELENG_4_11, or RELENG_4_10 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 4.10, 4.11, 5.3, and 5.4 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CE...14/bzip2.patch # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CE...zip2.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/lib/libbz2 # make obj && make depend && make && make install # cd /usr/src/usr.bin/bzip2 # make obj && make depend && make && make install VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - ------------------------------------------------------------------------- RELENG_4 contrib/bzip2/bzip2.c 1.1.1.1.2.3 contrib/bzip2/bzlib.c 1.1.1.1.2.3 contrib/bzip2/compress.c 1.1.1.1.2.3 contrib/bzip2/decompress.c 1.1.1.1.2.3 contrib/bzip2/huffman.c 1.1.1.1.2.3 RELENG_4_11 src/UPDATING 1.73.2.91.2.12 src/sys/conf/newvers.sh 1.44.2.39.2.15 contrib/bzip2/bzip2.c 1.1.1.1.2.2.12.1 contrib/bzip2/bzlib.c 1.1.1.1.2.2.12.1 contrib/bzip2/compress.c 1.1.1.1.2.2.12.1 contrib/bzip2/decompress.c 1.1.1.1.2.2.12.1 contrib/bzip2/huffman.c 1.1.1.1.2.2.12.1 RELENG_4_10 src/UPDATING 1.73.2.90.2.17 src/sys/conf/newvers.sh 1.44.2.34.2.18 contrib/bzip2/bzip2.c 1.1.1.1.2.2.10.1 contrib/bzip2/bzlib.c 1.1.1.1.2.2.10.1 contrib/bzip2/compress.c 1.1.1.1.2.2.10.1 contrib/bzip2/decompress.c 1.1.1.1.2.2.10.1 contrib/bzip2/huffman.c 1.1.1.1.2.2.10.1 RELENG_5 contrib/bzip2/bzip2.c 1.1.1.2.8.1 contrib/bzip2/bzlib.c 1.1.1.2.8.1 contrib/bzip2/compress.c 1.1.1.2.8.1 contrib/bzip2/decompress.c 1.1.1.2.8.1 contrib/bzip2/huffman.c 1.1.1.2.8.1 RELENG_5_4 src/UPDATING 1.342.2.24.2.12 src/sys/conf/newvers.sh 1.62.2.18.2.8 contrib/bzip2/bzip2.c 1.1.1.2.12.1 contrib/bzip2/bzlib.c 1.1.1.2.12.1 contrib/bzip2/compress.c 1.1.1.2.12.1 contrib/bzip2/decompress.c 1.1.1.2.12.1 contrib/bzip2/huffman.c 1.1.1.2.12.1 RELENG_5_3 src/UPDATING 1.342.2.13.2.20 src/sys/conf/newvers.sh 1.62.2.15.2.22 contrib/bzip2/bzip2.c 1.1.1.2.10.1 contrib/bzip2/bzlib.c 1.1.1.2.10.1 contrib/bzip2/compress.c 1.1.1.2.10.1 contrib/bzip2/decompress.c 1.1.1.2.10.1 contrib/bzip2/huffman.c 1.1.1.2.10.1 - ------------------------------------------------------------------------- VII. References http://cve.mitre.org/cgi-bin/cvename...=CAN-2005-0953 http://cve.mitre.org/cgi-bin/cvename...=CAN-2005-1260 http://marc.theaimsgroup.com/?l=bugt...11229375217633 http://scary.beasts.org/security/CESA-2005-002.txt The latest revision of this advisory is available at ftp://ftp.freebsd.org/pub/FreeBSD/CE...05:14.bzip.asc