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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2008.0224 -- [NetBSD] Endianness issue in fast_ipsec(4) 29 February 2008 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: kernel Publisher: NetBSD Operating System: NetBSD Impact: Reduced Security Access: Remote/Unauthenticated Original Bulletin: ftp://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2008-002.txt.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 NetBSD Security Advisory 2008-002 ================================= Topic: Endianness issue in fast_ipsec(4) Version: NetBSD-current: 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: IPSEC Security bypass Fixed: NetBSD-current: October 28, 2007 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 ======== If a IPsec association is made between two hosts with different byte orders it is possible to bypass the IPsec policy. It is possible for this situation to occur if a NetBSD system is just one host, or both hosts, involved in the IPsec connection. Technical Details ================= The function ipsec4_get_ulp() assumes that ip_off is host endian. This means that IPsec processing, that is dependent on protocol and/or port number, can be bypassed. Solutions and Workarounds ========================= Only kernels compiled with the following option are vulnerable to this issue: options FAST_IPSEC As a temporary workaround recompile the kernel with the above option commented out. The default NetBSD GENERIC kernels (with the exception of GENERIC.FAST_IPSEC) 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/netipsec/xform_ah.c \ sys/netipsec/ipsec.c \ sys/netipsec/xform_ipip.c \ sys/netipsec/ipsec_output.c \ sys/netipsec/ipsec_osdep.h # ./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 ========= Karl Knutsson for reporting this issue and supplying an initial fix. Arnaud Degroote for coming up with a final patch. 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-SA2008-002.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-SA2008-002.txt,v 1.3 2008/02/28 19:27:42 adrianp Exp $ - -----BEGIN PGP SIGNATURE----- iQCVAwUBR8cLgD5Ru2/4N2IFAQIF9AQAi85p580Da0TCm4NAYZb4u9pqqgtXD5ey qiecbr1l2fmPjtEg3bNQ6ZYBJnvHS2dcBJVs3Z7MgOyzPWS0vaAD96mIcOu0HVny +tISXCU2GAl90SrZK8KWJQfsOHSwKCg1pZbmhm9gTdzYAZNUQljZrnjznQCIWEGt rPk05KnfT2Q= =etlK - -----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. NOTE: Third Party Rights 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 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 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 iQCVAwUBR8dnjih9+71yA2DNAQLsEQP+JmJvD+Wan/UIMAweyAMCq+pxq6tekdNY SjjGAx7vHwu0yWixvBEKSfmHZ+2UNBhqAlAvNHEYKASfCNVx0OyWtiLJnFAFdfPR d6qOvMfMlfr+1Qfzk3yZTbr2m+c1AzrWDW3fBuA7SdLtMtaGfykXu+qMK02NfapW h3MBUvPPLWs= =diyM -----END PGP SIGNATURE-----