Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2004.0338 -- NetBSD Security Advisory 2004-007
Systrace systrace_exit() local root
13 May 2004
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: kernel
Publisher: NetBSD
Operating System: NetBSD-current
NetBSD 2.0 branch
Impact: Root Compromise
Access Required: Existing Account
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
NetBSD Security Advisory 2004-007
=================================
Topic: Systrace systrace_exit() local root
Version: NetBSD-current: source prior to Apr 16, 2004
netBSD 2.0 branch: source prior to Apr 16, 2004
netBSD 1.6.2: not affected
NetBSD 1.6.1: not affected
NetBSD 1.6: not affected
NetBSD-1.5.3: not affected
NetBSD-1.5.2: not affected
NetBSD-1.5.1: not affected
NetBSD-1.5: not affected
Severity: local root exploit
Fixed: NetBSD-current: Apr 17, 2004
NetBSD-2.0 branch: Apr 17, 2004 (2.0 will include
the fix)
Abstract
========
A local user that is allowed to use /dev/systrace can obtain root
access.
Technical Details
=================
systrace_exit() did not check if the connection to systrace was owned by
the super user, and would set euid to 0 on exit.
Solutions and Workarounds
=========================
*** Patching from sources:
The fix for this issue is contained in the one file,
sys/kern/kern_systrace.c
The following table lists the fixed revisions and
dates of this file for each branch:
CVS branch revision date
------------- ----------- ----------------
HEAD 1.38 2004/04/17
netbsd-2-0 1.37.2.1 2004/04/17
The following instructions describe how to upgrade your kernel
binaries by updating your source tree and rebuilding and installing a
new version of the kernel. In these instructions, replace:
BRANCH with the appropriate CVS branch (from the above table)
ARCH with your architecture (from uname -m), and
KERNCONF with the name of your kernel configuration file.
To update from CVS, re-build, and re-install the kernel:
# cd src
# cvs update -d -P -r BRANCH sys/kern/sysv_shm.c
# cd sys/arch/ARCH/conf
# config KERNCONF
# cd ../compile/KERNCONF
# make depend;make
# mv /netbsd /netbsd.old
# cp netbsd /
# reboot
* Binary Patch:
Binary patches are being provided, in the form of replacement
kernels built with the patches from the GENERIC kernel
configuration. If you use a custom kernel configuration, these
may not be suitable for you.
netbsd-current:
Releng does not compile -current kernels during a release cycle.
Users of -current are expected to be capable of upgrading from
sources.
netbsd-2-0:
Retreive a kernel from:
ftp://releng.netbsd.org/pub/NetBSD-daily/netbsd-2-0/DATE/ARCH/binary/kernel/
Where DATE is any available DATE later than 2004-04-17
Thanks To
=========
Stefan Esser for detection and notification
Niels Provos for patches
Revision History
================
2004-05-12 Initial release
More Information
================
Advisories may be updated as new information becomes available.
The most recent version of this advisory (PGP signed) can be found at
ftp://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2004-007.txt.asc
Information about NetBSD and NetBSD security can be found at
http://www.NetBSD.org/ and http://www.NetBSD.org/Security/.
Copyright 2004, The NetBSD Foundation, Inc. All Rights Reserved.
Redistribution permitted only in full, unmodified form.
$NetBSD: NetBSD-SA2004-007.txt,v 1.2 2004/05/12 15:39:10 david Exp $
- -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.3 (NetBSD)
iQCVAwUBQKJFLz5Ru2/4N2IFAQEaTgQAhGSQG1/cWAjKSV95hZ5dej1tkA+eYEMO
Y8EuSm80ebavAb4gJnvm5AcpnWu8THZgMdALNcJ+E7cK9wzCF8XfLHy/hHRPCcgr
Q/2vtood5T/ZdDdWJ9RXPBxR6GtAGvHXdhBqHWxTdN8OmaX36N1TptQ4mI9QoeWf
PTIeZpnsSBw=
=RBZ+
- -----END PGP SIGNATURE-----
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
http://www.auscert.org.au/render.html?cid=1980
If you believe that your computer system has been compromised or attacked in
any way, we encourage you to let us know by completing the secure National IT
Incident Reporting Form at:
http://www.auscert.org.au/render.html?it=3192
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business
hours which are GMT+10:00 (AEST). On call after hours
for member emergencies only.
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967
iQCVAwUBQKMeFSh9+71yA2DNAQIUCAP+MGot7OkZUuHuySpSWehR7b/Kq1hizn16
SAoHH1EP4pB/xSQxfJ5vcCRqI89j4/YxJFA1xnS1VwiWriHgut+CuWlStnbXVE9g
WtJ/yIncNWHSRQ6wOx7j8kHp8zYrdC9BnMkTMyY+hidIzSKL84c8Q2/4ap7quhqx
cm8WtWZMP78=
=+n/n
-----END PGP SIGNATURE-----