TITLE: OpenSSL Potential SSL 2.0 Rollback Vulnerability SECUNIA ADVISORY ID: SA17151 VERIFY ADVISORY: http://secunia.com/advisories/17151/ CRITICAL: Less critical IMPACT: Security Bypass WHERE: >From remote SOFTWARE: OpenSSL 0.9.x http://secunia.com/product/253/ DESCRIPTION: A vulnerability has been reported in OpenSSL, which potentially can be exploited by malicious people to bypass certain security restrictions. The vulnerability is caused due to an error in handling the use of SSL_OP_MSIE_SSLV2_RSA_PADDING option. The use of this option causes a verification check that prevents protocol-version rollback attacks to be disabled. This may be exploited in "man-in-the-middle" attacks to force a client and a server to negotiate the less secure SSL 2.0 protocol even when both parties support the more secure SSL 3.0 or TLS 1.0 protocols. The option is also enabled when the SSL_OP_ALL option is used. Successful exploitation requires that SSL 2.0 is enabled, and either the SSL_OP_MSIE_SSLV2_RSA_PADDING or the SSL_OP_ALL option is used. The vulnerability has been reported in all versions prior to 0.9.7h, and prior to 0.9.8a. Applications that use the OpenSSL SSL/TLS server implementation are potentially affected. SOLUTION: Update to the fixed versions or apply patch. http://www.openssl.org/source/ OpenSSL 0.9.7 branch: Update to version 0.9.7h or later. OpenSSL 0.9.8 branch: Update to version 0.9.8a or later. The vendor provides the following source code patch for the 0.9.6, 0.9.7, and 0.9.8 OpenSSL branches for users who are unable to perform a version update. http://www.openssl.org/news/patch-CAN-2005-2969.txt PROVIDED AND/OR DISCOVERED BY: The vendor credits Yutaka Oiwa, Research Center for Information Security, National Institute of Advanced Industrial Science and Technology (AIST), Japan. ORIGINAL ADVISORY: http://www.openssl.org/news/secadv_20051011.txt ---------------------------------------------------------------------- About: This Advisory was delivered by Secunia as a free service to help everybody keeping their systems up to date against the latest vulnerabilities. Subscribe: http://secunia.com/secunia_security_advisories/ Definitions: (Criticality, Where etc.) http://secunia.com/about_secunia_advisories/ Please Note: Secunia recommends that you verify all advisories you receive by clicking the link. Secunia NEVER sends attached files with advisories. Secunia does not advise people to install third party patches, only use those supplied by the vendor. ---------------------------------------------------------------------- Unsubscribe: Secunia Security Advisories http://secunia.com/sec_adv_unsubscribe/?email=packet%40packetstormsecurity.org ----------------------------------------------------------------------