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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2005.0890 -- NetBSD Security Advisory 2005-010 OpenSSL "man in the middle" can force weak protocol 8 November 2005 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: OpenSSL Publisher: NetBSD Operating System: NetBSD-current (source prior to October 11, 2005) NetBSD 2.0.2 and prior Impact: Reduced Security Access Confidential Data CVE Names: CAN-2005-2969 Ref: ESB-2005.0801 Original Bulletin: ftp://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2005-010.txt.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 NetBSD Security Advisory 2005-010 ================================= Topic: OpenSSL "man in the middle" can force weak protocol Version: NetBSD-current: source prior to October 11, 2005 NetBSD 2.1: not affected NetBSD 2.0.3: not affected NetBSD 2.0.2: affected NetBSD 2.0: affected NetBSD 1.6.*: affected pkgsrc: openssl packages prior to 0.9.7h Severity: information leak due to false sense of security Fixed: NetBSD-current: October 11, 2005 NetBSD-3 branch: October 11, 2005 (3.0 will include the fix) NetBSD-2.0 branch: October 11, 2005 (2.0.3 includes the fix) NetBSD-2 branch: October 11, 2005 (2.1 includes the fix) NetBSD-1.6 branch: October 11, 2005 (1.6.3 will include the fix) pkgsrc: openssl-0.9.7h corrects this issue Abstract ======== A vulnerability in OpenSSL allowed a malicious man-in-the-middle to force two endpoints of an SSL connection to negotiate using SSL 2.0, which is known to have severe cryptographic weaknesses. This vulnerability has been assigned CVE reference CAN-2005-2969. Technical Details ================= OpenSSL has an option SSL_OP_MSIE_SSLV2_RSA_PADDING to work around various bugs in third-party software that might prevent interoperability with OpenSSL. This option is implied by the use of SSL_OP_ALL. The said option disables a verification step in the SSL 2.0 server supposed to prevent active protocol-version rollback attacks; such attacks force the use of weaker protocols. With this verification step disabled, a man-in-the-middle can force a client and a server to negotiate the SSL 2.0 protocol, even if both parties support SSL 3.0 or TLS 1.0. Solutions and Workarounds ========================= A workaround is to completely disable SSL 2.0 in any application that uses OpenSSL. It is recommended that NetBSD users of vulnerable versions update their binaries. The following instructions describe how to upgrade your OpenSSL binaries by updating your source tree and rebuilding and installing a new version of OpenSSL. * NetBSD-current: Systems running NetBSD-current dated from before 2005-10-11 should be upgraded to NetBSD-current dated 2005-10-12 or later. The following files need to be updated from the netbsd-current CVS branch (aka HEAD): crypto/dist/openssl/ssl/s23_srvr.c crypto/dist/openssl/crypto/opensslv.h To update from CVS, re-build, and re-install OpenSSL: # cd src # cvs update -d -P crypto/dist/openssl/ssl/s23_srvr.c # cvs update -d -P crypto/dist/openssl/crypto/opensslv.h # cd lib/libcrypto # make USETOOLS=no cleandir dependall # make USETOOLS=no install * NetBSD 2.*: The binary distribution of NetBSD 2.0 is vulnerable. Systems running NetBSD 2.0 sources dated from before 2005-10-11 should be upgraded from NetBSD 2.0 sources dated 2005-10-12 or later. NetBSD 2.1 and 2.0.3 include the fix. The following files need to be updated from the netbsd-2 CVS branch: crypto/dist/openssl/ssl/s23_srvr.c crypto/dist/openssl/crypto/opensslv.h To update from CVS, re-build, and re-install OpenSSL: # cd src # cvs update -d -P -r netbsd-2 crypto/dist/openssl/ssl/s23_srvr.c # cvs update -d -P -r netbsd-2 crypto/dist/openssl/crypto/opensslv.h # cd lib/libcrypto # make USETOOLS=no cleandir dependall # make USETOOLS=no install * NetBSD 1.6.*: The binary distributions of NetBSD 1.6, 1.6.1, and 1.6.2 are vulnerable. Systems running NetBSD 1.6 sources dated from before 2005-10-11 should be upgraded from NetBSD 1.6 sources dated 2005-10-12 or later. NetBSD 1.6.3 will include the fix. The following files need to be updated from the netbsd-1-6 CVS branch: crypto/dist/openssl/ssl/s23_srvr.c crypto/dist/openssl/crypto/opensslv.h To update from CVS, re-build, and re-install OpenSSL: # cd src # cvs update -d -P -r netbsd-1-6 crypto/dist/openssl/ssl/s23_srvr.c # cvs update -d -P -r netbsd-1-6 crypto/dist/openssl/crypto/opensslv.h # cd lib/libcrypto # make USETOOLS=no cleandir dependall # make USETOOLS=no install Thanks To ========= Thanks to Yutaka Oiwa for reporting this issue to the OpenSSL team. Revision History ================ 2005-10-31 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-SA2005-010.txt.asc Information about NetBSD and NetBSD security can be found at http://www.NetBSD.org/ and http://www.NetBSD.org/Security/. Copyright 2005, The NetBSD Foundation, Inc. All Rights Reserved. Redistribution permitted only in full, unmodified form. $NetBSD: NetBSD-SA2005-010.txt,v 1.5 2005/10/31 22:21:02 dan Exp $ - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (NetBSD) iQCVAwUBQ2fJ7j5Ru2/4N2IFAQJimQP/Z04xQK/iej+Hvzqu2wWjRTug9Hp608IJ MtOck/ReIoRCGYMSsEVVBlH0nIZtdCK2scnjz4u2DWsZ8CCrGpy6tjR3TBib1zkZ VcH2eEBc3GJk66/nnJB3+yAy/7ce1GRFtFBdcrAa5Jve4bYFIu0INsRKGOS36b4F NaIdermbUrk= =t3d8 - -----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. 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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 iQCVAwUBQ2/3cCh9+71yA2DNAQINpgP9FUGtzFPX4vUZ0qpt6CgSKLPtE2i/1wTW IHEa/2LzUotoHiF9uwy4vlqm7sCxWD3k6vhH/sOR1pFU41UwKNZb9s3268xK+oso 8w/ph6bqnaOqj3guYwmfdg4Y55jui4FhQV9ZyZxpLvsUK69P1kNVcPxGI0cuCKOi tUD/owb0Foo= =yBHL -----END PGP SIGNATURE-----