__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN OpenSSL Potential SSL 2.0 Rollback [OpenSSL Security Advisory [11 October 2005]] October 11, 2005 16:00 GMT Number Q-007 [REVISED 17 Oct 2005] [REVISED 27 Oct 2005] [REVISED 31 Oct 2005] [REVISED 04 Nov 2005] [REVISED 29 Nov 2005] [REVISED 02 Dec 2005] [REVISED 07 Dec 2005] [REVISED 09 Dec 2005] [REVISED 19 Dec 2005] [REVISED 28 Dec 2005] [REVISED 10 Feb 2006] ______________________________________________________________________________ PROBLEM: A vulnerability has been found in all previously released versions of OpenSSL. Such applications are affected if they use the option SSL_OP_MSIE_SSLV2_RSA_PADDING. PLATFORM: all versions up to 0.9.7h and 0.9.8a Solaris 10 Operating System Red Hat Desktop (v. 3 and v. 4) Red Hat Enterprise Linux AS, ES, WS, (v. 2.1, v. 3 and v. 4) Red Hat Linux Advanced Workstation 2.1 for Itanium Processor SGI ProPack 3 Service Pack 6 Debian GNU/Linux 3.0 (woody) and 3.1 (sarge) Cisco ASA 5500 and Cisco PIX running 7.x software CiscoWorks Common Services (CWCS) version 3.0 and CiscoWorks Common Services (CWCS) version 2.2 Cisco Mainframe Channel Connection (CMCC) - PA-4C-E, PA-1C-E, PA-1C-P, CX-CIP2 tn3270 server Cisco Global Site Selector (4480, 4490, 4491) Cisco Wireless Control System Software Cisco IOS-XR HP HTTP Server versions earlier than version 5.9.7 running on Microsoft Windows 2000 Server and Windows 2003 DAMAGE: The SSL_OP_MSIE_SSLV2_RSA_PADDING option disables a verification step in the SSL 2.0 server supposed to prevent active protocol-version rollback attacks. SOLUTION: Upgrade to the appropriate version. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. An attacker acting as a "man in the middle" ASSESSMENT: can force a client and a server to negotiate the SSL 2.0 protocol even if these parties both support SSL 3.0 or TLS 1.0. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/q-007.shtml ORIGINAL BULLETIN: OpenSSL Security Advisory [11 October 2005] http://www.openssl.org/news/secadv_20051011.txt ADDITIONAL LINKS: Sun Alert ID: 101974 http://www.sunsolve.sun.com/search/document.do?assetkey= 1-26-101974-1&searchclause=%22category:security%22%20% 22availability,%20security%22%20category:security Debian Security Advisory DSA 875-1 http://www.debian.org/security/2005/dsa-875 Red Hat Security Advisory RHSA-2005:800-8 https://rhn.redhat.com/errata/RHSA-2005-800.html SGI Security Advisory Number 20051003-02-U ftp://patches.sgi.com/support/free/security/advisories/20051003-02-U.asc Debian Security Advisories DSA-881 and DSA-882 http://www.debian.org/security/2005/dsa-881 http://www.debian.org/security/2005/dsa-882 Cisco Security Notice Document ID: 68324 http://www.cisco.com/en/US/products/hw/contnetw/ps4162/products_security_notice09186a008059f218.html Visit Hewlett-Packard Subscription Service for: HPSBMA02093 / SSRT051102 CVE: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CVE-2005-2969 ______________________________________________________________________________ REVISION HISTORY: 10/17/2005 - revised to add a link to Sun Alert ID: 101974 for Solaris 10 Operating System. 10/27/2005 – revised to add a link to Debian Security Advisory DSA-875-1 10/31/2005 - revised to add links to Red Hat Security Advisory RHSA-2005:800 and SGI Advanced Linux Environment 3 Security Update #50, providing patches for this vulnerability. 11/04/2005 - revised to add links to Debian Security Advisories DSA-881 and DSA-882 that provides updated openssl packages for 'woody' and 'sarge'. 11/29/2005 - Sun updated the Contributing Factors and Resolution section in Sun Alert 101974. Status was also updated to "resolved". 12/02/2005 - revised to include a link to Cisco Security Notice Document 68324 that provides Cisco's response to this vulnerability. 12/07/2005 - revised to note that Cisco has revised their Security Notice 68324 to remove "Common Services (NMTG) and Cisco Call Manager from Products not Affected section. 12/09/2005 - revised to note that Cisco has revised their Security Notice 68324 to update Affected Products Section - "Cisco Mainframe Channel Connection (CMCC)" entry. 12/19/2005 - revised to note that Cisco has revised their Security Notice 68324 to update Affected Products Section - "Cisco IOS-XR" entry. 12/28/2005 - revised to note that Cisco has revised their Security Notice 68324 to update Affected Products Section - "Cisco IOS-XR" entry. 02/10/2006 - added reference to HP's Security Bulletin HPSBMA02093 / SSRT051102 that provides updates addressing this vulnerability. [***** Start OpenSSL Security Advisory [11 October 2005] *****] OpenSSL Security Advisory [11 October 2005] Potential SSL 2.0 Rollback (CAN-2005-2969) ========================================== CONTENTS - Vulnerability - Recommendations - Acknowledgement - References Vulnerability ------------- A vulnerability has been found in all previously released versions of OpenSSL (all versions up to 0.9.7h and 0.9.8a). Versions 0.9.7h and 0.9.8a have been released to address the issue. The vulnerability potentially affects applications that use the SSL/TLS server implementation provided by OpenSSL. Such applications are affected if they use the option SSL_OP_MSIE_SSLV2_RSA_PADDING. This option is implied by use of SSL_OP_ALL, which is intended to work around various bugs in third-party software that might prevent interoperability. The SSL_OP_MSIE_SSLV2_RSA_PADDING option disables a verification step in the SSL 2.0 server supposed to prevent active protocol-version rollback attacks. With this verification step disabled, an attacker acting as a "man in the middle" can force a client and a server to negotiate the SSL 2.0 protocol even if these parties both support SSL 3.0 or TLS 1.0. The SSL 2.0 protocol is known to have severe cryptographic weaknesses and is supported as a fallback only. Applications using neither SSL_OP_MSIE_SSLV2_RSA_PADDING nor SSL_OP_ALL are not affected. Also, applications that disable use of SSL 2.0 are not affected. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2005-2969 to this issue. Recommendations --------------- There are multiple ways to avoid this vulnerability. Any one of the following measures is sufficient. 1. Disable SSL 2.0 in the OpenSSL-based application. The vulnerability occurs only if the old protocol version SSL 2.0 is enabled both in an OpenSSL server and in any of the clients (OpenSSL-based or not) connecting to it. Thus, if you have disabled SSL 2.0, the vulnerability does not apply to you. Generally, it is strongly recommended to disable the SSL 2.0 protocol because of its known weaknesses. 2. Upgrade the OpenSSL server software. The vulnerability is resolved in the following versions of OpenSSL: - in the 0.9.7 branch, version 0.9.7h (or later); - in the 0.9.8 branch, version 0.9.8a (or later). OpenSSL 0.9.8a and OpenSSL 0.9.7h are available for download via HTTP and FTP from the following master locations (you can find the various FTP mirrors under http://www.openssl.org/source/mirror.html): o http://www.openssl.org/source/ o ftp://ftp.openssl.org/source/ The distribution file names are: o openssl-0.9.8a.tar.gz MD5 checksum: 1d16c727c10185e4d694f87f5e424ee1 SHA1 checksum: 2aaba0f728179370fb3e86b43209205bc6c06a3a o openssl-0.9.7h.tar.gz MD5 checksum: 8dc90a113eb8925795071fbe52b2932c SHA1 checksum: 9fe535fce89af967b29c4727dedd25f2b4cc2f0d The checksums were calculated using the following commands: openssl md5 openssl-0.9*.tar.gz openssl sha1 openssl-0.9*.tar.gz If this version upgrade is not an option at the present time, alternatively the following patch may be applied to the OpenSSL source code to resolve the problem. The patch is compatible with the 0.9.6, 0.9.7, and 0.9.8 branches of OpenSSL. o http://www.openssl.org/news/patch-CAN-2005-2969.txt Whether you choose to upgrade to a new version or to apply the patch, make sure to recompile any applications statically linked to OpenSSL libraries if these applications use the OpenSSL SSL/TLS server implementation. Acknowledgement --------------- The OpenSSL team thank Yutaka Oiwa of the Research Center for Information Security, National Institute of Advanced Industrial Science and Technology (AIST), Japan, for alerting us about this problem. References ---------- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-2969 URL for this Security Advisory: http://www.openssl.org/news/secadv_20051011.txt [***** End OpenSSL Security Advisory [11 October 2005] *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of OpenSSL for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. 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