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		 NetBSD Security Advisory 2009-002
		 =================================

Topic:		tcpdump multiple denial of service and arbitrary code
		execution issues

Version:	NetBSD-current:		affected before July 20, 2007
		NetBSD 5.0:		not affected
		NetBSD 4.0.*:		not affected
		NetBSD 4.0:		affected

Severity:	Denial of Service, Arbitrary Code Execution

Fixed:		NetBSD-current:		July 20, 2007
		NetBSD-4-0 branch:	June 21, 2009
			(4.0.2 will include the fix)
		NetBSD-4 branch:	June 21, 2009
			(4.1 will include the fix)
		pkgsrc:			tcpdump-3.9.7 corrects the issue

Please note that NetBSD releases prior to 4.0 are no longer supported.
It is recommended that all users upgrade to a supported release.


Abstract
========

A number of issuses exist in the version of tcpdump(1) shipped with
NetBSD 4.0 allowing a remote attacker to hang or crash the
application and to execute arbitrary code via specially crafted
packages.


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

An integer overflow in the BGP dissector allows remote attackers
to execute arbitrary code via crafted TLVs in a BGP packet.

An infinite loop error in the BGP dissector allows remote attackers
to cause an application hang by sending an invalid prefix.

An off-by-one error in the 802.11 dissector result printing code
allows remote attackers to crash the application.

An infinite loop error in the ISIS dissector allows remote attackers
to cause an application hang using GRE packets of zero length.

A length verification error in the RSVP dissector allows remote
attackers to crash the application by sending a RSVP packet of
length 4.

For more details, please see CVE-2007-1218, CVE-2007-3798,
CAN-2005-1267, CAN-2005-1278, CAN-2005-1279 and CAN-2005-1280.


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

The 4.0.1 release of NetBSD resolves this issue, so a possible
solution is to upgrade to NetBSD 4.0.1 or 5.0.
As a temporary workaround disable tcpdump(1) from the base OS and use the
tcpdump-3.9.7 package from pkgsrc which contains a fix.

The following instructions describe how to upgrade your tcpdump
binaries by updating your source tree and rebuilding and
installing a new version of tcpdump.

* NetBSD-current:

	Systems running NetBSD-current dated from before 2007-07-20
	should be upgraded to NetBSD-current dated 2007-07-21 or later.

	The following directories need to be updated from the
	netbsd-current CVS branch (aka HEAD):
		dist/tcpdump

	To update from CVS, re-build, and re-install tcpdump:
		# cd src
		# cvs update -d -P dist/tcpdump
		# cd usr.sbin/tcpdump

		# make USETOOLS=no cleandir dependall
		# make USETOOLS=no install

* NetBSD 4.0:

	The binary distribution of NetBSD 4.0 is vulnerable.

	Systems running NetBSD 4.0 sources dated from before
	2009-06-21 should be upgraded from NetBSD 4.0 sources dated
	2009-06-22 or later.

	The following directories need to be updated from the
	netbsd-4 CVS branch:
		dist/tcpdump

	To update from CVS, re-build, and re-install tcpdump:

		# cd src
		# cvs update -d -P -r netbsd-4-0 dist/tcpdump
		# cd usr.sbin/tcpdump

		# make USETOOLS=no cleandir dependall
		# make USETOOLS=no install


Thanks To
=========

Moritz Jodeit, mu-b of digit-labs.org and Vade79 for finding and
reporting the issue.


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

	2009-06-22	Initial release
	2009-06-25	Corrected the dates of the 4.0 fix


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-SA2009-002.txt.asc

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


Copyright 2009, The NetBSD Foundation, Inc.  All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2009-002.txt,v 1.3 2009/06/25 05:46:48 tonnerre Exp $

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