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AUSCERT External Security Bulletin Redistribution
ESB-2005.0480 -- FreeBSD-SA-05:14.bzip2
bzip2 denial of service and permission race vulnerabilities
30 June 2005
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: bzip2
Publisher: FreeBSD
Operating System: FreeBSD
Impact: Modify Permissions
Denial of Service
Access: Remote/Unauthenticated
CVE Names: CAN-2005-1260 CAN-2005-0953
Ref: ESB-2005.0461
Original Bulletin: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/Advisories/FreeBSD-SA-05:14.bzip2.asc
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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/CERT/patches/SA-05:14/bzip2.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:14/bzip2.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
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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.cgi?name=CAN-2005-0953
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1260
http://marc.theaimsgroup.com/?l=bugtraq&m=111229375217633
http://scary.beasts.org/security/CESA-2005-002.txt
The latest revision of this advisory is available at
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:14.bzip.asc
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