Date: 19 November 2004
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===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2004.0734 -- FreeBSD-SA-04:16.fetch
Overflow error in fetch
19 November 2004
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: fetch
Publisher: FreeBSD
Operating System: FreeBSD
Impact: Execute Arbitrary Code/Commands
Access: Remote/Unauthenticated
Original Bulletin: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-04:16.fetch.asc
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=============================================================================
FreeBSD-SA-04:16.fetch Security Advisory
The FreeBSD Project
Topic: Overflow error in fetch
Category: core
Module: fetch
Announced: 2004-11-18
Credits: Colin Percival
Affects: All FreeBSD versions.
Corrected: 2004-11-18 12:02:13 UTC (RELENG_5, 5.3-STABLE)
2004-11-18 12:03:05 UTC (RELENG_5_3, 5.3-RELEASE-p1)
2004-11-18 12:04:29 UTC (RELENG_5_2, 5.2.1-RELEASE-p12)
2004-11-18 12:05:36 UTC (RELENG_5_1, 5.1-RELEASE-p18)
2004-11-18 12:05:50 UTC (RELENG_5_0, 5.0-RELEASE-p22)
2004-11-18 12:02:29 UTC (RELENG_4, 4.10-STABLE)
2004-11-18 12:06:06 UTC (RELENG_4_10, 4.10-RELEASE-p4)
2004-11-18 12:06:22 UTC (RELENG_4_9, 4.9-RELEASE-p13)
2004-11-18 12:06:36 UTC (RELENG_4_8, 4.8-RELEASE-p26)
2004-11-18 12:06:52 UTC (RELENG_4_7, 4.7-RELEASE-p28)
FreeBSD only: YES
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
The fetch(1) utility is a tool for fetching files via FTP, HTTP, and HTTPS.
II. Problem Description
An integer overflow condition in the processing of HTTP headers can result
in a buffer overflow.
III. Impact
A malicious server or CGI script can respond to an HTTP or HTTPS request in
such a manner as to cause arbitrary portions of the client's memory to be
overwritten, allowing for arbitrary code execution.
IV. Workaround
There is no known workaround for the affected application, although
the ftp(1) application in the FreeBSD base system, and several
applications in the FreeBSD Ports collection provide similar
functionality and could be used in place of fetch(1).
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 4-STABLE or 5-STABLE, or to the
RELENG_5_3, RELENG_5_2, RELENG_4_10, or RELENG_4_8 security branch dated
after the correction date.
2) To patch your present system:
The following patches have been verified to apply to FreeBSD 4.8, 4.10,
5.2, and 5.3 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# ftp ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:16/fetch.patch
# ftp ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:16/fetch.patch.asc
b) Execute the following commands as root:
# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/usr.bin/fetch
# make obj && make depend && make && make install
3) IMPORTANT NOTE to users of FreeBSD Update:
FreeBSD Update (security/freebsd-update in the FreeBSD Ports collection)
is a binary security update system for the FreeBSD base system. It is
not supported or endorsed by the FreeBSD Security team, but its author
has requested that the following note be included in this advisory:
FreeBSD Update uses the fetch(1) utility for downloading security
updates to the FreeBSD base system. While these updates are
cryptographically signed, and FreeBSD Update is therefore immune from
most attacks, it is exposed to this vulnerability since the files
must be fetched before their integrity can be verified.
As a workaround, FreeBSD Update can be made to use the ftp(1) utility
for downloading updates as follows:
# sed -i.bak -e 's/fetch -qo/ftp -o/' /usr/local/sbin/freebsd-update
# freebsd-update fetch
# mv /usr/local/sbin/freebsd-update.bak /usr/local/sbin/freebsd-update
# freebsd-update install
VI. Correction details
The following list contains the revision numbers of each file that was
corrected in FreeBSD.
Branch Revision
Path
- - -------------------------------------------------------------------------
RELENG_4
src/usr.bin/fetch/fetch.c 1.10.2.28
RELENG_4_10
src/UPDATING 1.73.2.90.2.5
src/sys/conf/newvers.sh 1.44.2.34.2.6
src/usr.bin/fetch/fetch.c 1.10.2.23.2.1
RELENG_4_9
src/UPDATING 1.73.2.89.2.14
src/sys/conf/newvers.sh 1.44.2.32.2.14
src/usr.bin/fetch/fetch.c 1.10.2.21.2.1
RELENG_4_8
src/UPDATING 1.73.2.80.2.29
src/sys/conf/newvers.sh 1.44.2.29.2.27
src/usr.bin/fetch/fetch.c 1.10.2.20.2.1
RELENG_4_7
src/UPDATING 1.73.2.74.2.32
src/sys/conf/newvers.sh 1.44.2.26.2.30
src/usr.bin/fetch/fetch.c 1.10.2.18.2.1
RELENG_5
src/usr.bin/fetch/fetch.c 1.72.2.2
RELENG_5_3
src/UPDATING 1.342.2.13.2.4
src/sys/conf/newvers.sh 1.62.2.15.2.6
src/usr.bin/fetch/fetch.c 1.72.2.1.2.1
RELENG_5_2
src/UPDATING 1.282.2.20
src/sys/conf/newvers.sh 1.56.2.19
src/usr.bin/fetch/fetch.c 1.62.4.1
RELENG_5_1
src/UPDATING 1.251.2.20
src/sys/conf/newvers.sh 1.50.2.20
src/usr.bin/fetch/fetch.c 1.62.2.1
RELENG_5_0
src/UPDATING 1.229.2.28
src/sys/conf/newvers.sh 1.48.2.23
src/usr.bin/fetch/fetch.c 1.58.2.1
- - -------------------------------------------------------------------------
VII. References
<other info on vulnerability>
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