NetBSD Security Advisory 2008-003: IPsec in IPv6 Denial of Service

[NetBSD Security-Officer <security-officer%netbsd.org@localhost>]

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                 NetBSD Security Advisory 2008-003
                 =================================

Topic:          IPsec in IPv6 Denial of Service

Version:        NetBSD-current:         not affected
                NetBSD 4.0:             not affected
                NetBSD 3.1:             affected
                NetBSD 3.0.*:           affected
                NetBSD 3.0:             affected
                NetBSD 2.1:             affected
                NetBSD 2.0.*:           affected
                NetBSD 2.0:             affected

Severity:       Remote denial of service

Fixed:          NetBSD-3-1 branch:      November 22, 2007
                        (3.1.2 will include the fix)
                NetBSD-3-0 branch:      November 22, 2007
                        (3.0.4 will include the fix)
                NetBSD-3 branch:        November 22, 2007
                        (3.2 will include the fix)
                NetBSD-2-1 branch:      December 01, 2007
                NetBSD-2-0 branch:      December 01, 2007
                NetBSD-2 branch:        December 01, 2007


Abstract
========

A remote user can cause the system to panic by sending a crafted IPv6
packet to a system with an IPSEC enabled kernel.

This vulnerability has been assigned VU#110947 by CERT.


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

When processing an IPComp packet over IPv6 with an IPsec enabled kernel
an uninitialised pointer is referenced which results in a system panic.


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

Only kernels compiled with the following option are vulnerable to this issue:

        options IPSEC

As a temporary workaround recompile the kernel with the above option 
commented out.  The default NetBSD GENERIC kernels do not have this
option enabled.

For all NetBSD versions, you need to obtain fixed kernel sources,
rebuild and install the new kernel, and reboot the system.
                                      
The fixed source may be obtained from the NetBSD CVS repository.
The following instructions briefly summarise how to upgrade your
kernel.  In these instructions, replace:

   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 sys/netinet6/ipcomp_input.c
        # ./build.sh kernel=KERNCONF
        # mv /netbsd /netbsd.old
        # cp sys/arch/ARCH/compile/obj/KERNCONF/netbsd /netbsd
        # shutdown -r now

For more information on how to do this, see:

   http://www.NetBSD.org/guide/en/chap-kernel.html


Thanks To
=========

Takashi Sogabe of Internet Initiative Japan Inc. for reporting this issue.


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

        2008-02-28      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-SA2008-003.txt.asc

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


Copyright 2008, The NetBSD Foundation, Inc.  All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2008-003.txt,v 1.3 2008/02/28 19:27:42 adrianp Exp $

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