Exploitable bugs in kerberised telnetd and libkrb

-----BEGIN PGP SIGNED MESSAGE-----

===========================================================================
              AUSCERT External Security Bulletin Redistribution
                             
              ESB-2000.403 -- NetBSD Security Advisory 2000-017
              Exploitable bugs in kerberised telnetd and libkrb
                              22 December 2000

===========================================================================

	AusCERT Security Bulletin Summary
	---------------------------------

Product:                telnetd, libkrb
Vendor:                 NetBSD
Operating System:       NetBSD
Impact:                 Root Compromise
Access Required:        Local

- --------------------------BEGIN INCLUDED TEXT--------------------

- -----BEGIN PGP SIGNED MESSAGE-----

                 NetBSD Security Advisory 2000-017
                 =================================

Topic:		Exploitable bugs in kerberised telnetd and libkrb
Version:	1.5
Severity:	local root compromise possible
Fixed:		2000/12/09 in -current; 2000/12/15 in netbsd-1-5-branch

Abstract
========

The combination of a too liberal implementation in telnetd and bugs in
libkrb combines to make it possible for authorized users of a system
to obtain root access on a system.

Technical Details
=================

there were two problems; first, telnetd allowed the user to provide
arbitrary environment variables, including several that cause programs
to behave differently.  There was also a possible buffer overflow in
the kerberos v4 library.

Solutions and Workarounds
=========================

The problem was fixed in NetBSD-current on 2000/12/09; systems running
NetBSD-current dated from before that date should be upgraded to
NetBSD-current dated 2000/12/09 or later.  The 1.5 branch was
fixed by 2000/12/15.

Systems running 1.4.x are not vulnerable to this problem as they do
not contain this version of kerberos.

Systems running 1.5 should apply the patch found in
    ftp://ftp.NetBSD.ORG/pub/NetBSD/misc/security/patches/20001220-krb
and then rebuild and reinstall both the "libkrb" library and telnetd.

Systems running NetBSD-current dated from before 2000/12/09 should be
upgraded to NetBSD-current dated 2000/12/09 or later.

Thanks To
=========

Jouko Pynnönen <jouko@solutions.fi>

Revision History
================

20001215	First draft

More Information
================

Information about NetBSD and NetBSD security can be found at
http://www.NetBSD.ORG/ and http://www.NetBSD.ORG/Security/.


Copyright 2000, The NetBSD Foundation, Inc.  All Rights Reserved.

$NetBSD: NetBSD-SA2000-017.txt,v 1.5 2000/12/20 20:30:13 sommerfeld Exp $

- -----BEGIN PGP SIGNATURE-----
Version: 2.6.3ia
Charset: noconv

iQCVAwUBOkEW3j5Ru2/4N2IFAQHOmwP8D/+PSPdMwwo4G22IX2820iRitmUBU7c/
moB6TaEw9CPMzAmd3499Kx/Xe+IRMFEFgDZOJVDZx/tgqWR2Xpd/caQiAM/9c0Th
uVRW/A5EgSm7mUnUk82KHnySpqKn+Cnr1ytR9a+HuaSpn0O/Q0yHslg95G+VYQ2W
f31W26+Q21M=
=hboe
- -----END PGP SIGNATURE-----

- --------------------------END INCLUDED TEXT--------------------

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 use any or all of this information is
the responsibility of each user or organisation, and should be done so in
accordance with site policies and procedures.

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 original authors 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/Information/advisories.html

If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security
Teams).

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 emergencies.


-----BEGIN PGP SIGNATURE-----
Version: 2.6.3i
Charset: noconv
Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key

iQCVAwUBOlSNcyh9+71yA2DNAQFogQP8CDLgm7pEU234jDuUQIrgRMIq/uNTQjSn
EcuLQjMB0Ag2HuCuMQUluWrKgs1yEAa+veGo1gEdsDnBaRnQYWTsoIr3fi37ehcA
Vth+/SPrPQ+5M0DT/Oh5dChEbRT67GCrUu/ZJx5rZdqhV8zWPOgK7yM9+UebLgQg
lCcyHaIgS1o=
=0YB7
-----END PGP SIGNATURE-----