OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL v2/v3)and Transport Layer Security (TLS v1) protocols, as well as afull-strength, general purpose cryptography library.A flaw was found in the way the TLS/SSL (Transport Layer Security/SecureSockets Layer) protocols handled session renegotiation. A man-in-the-middleattacker could use this flaw to prefix arbitrary plain text to a client'ssession (for example, an HTTPS connection to a website). This could forcethe server to process an attacker's request as if authenticated using thevictim's credentials. This update addresses this flaw by implementing theTLS Renegotiation Indication Extension, as defined in RFC 5746.(CVE-2009-3555)Refer to the following Knowledgebase article for additional details aboutthe CVE-2009-3555 flaw: http://kbase.redhat.com/faq/docs/DOC-20491Dan Kaminsky found that browsers could accept certificates with MD2 hashsignatures, even though MD2 is no longer considered a cryptographicallystrong algorithm. This could make it easier for an attacker to create amalicious certificate that would be treated as trusted by a browser.OpenSSL now disables the use of the MD2 algorithm inside signatures bydefault. (CVE-2009-2409)An input validation flaw was found in the handling of the BMPString andUniversalString ASN1 string types in OpenSSL's ASN1_STRING_print_ex()function. An attacker could use this flaw to create a specially-craftedX.509 certificate that could cause applications using the affected functionto crash when printing certificate contents. (CVE-2009-0590)Note: The affected function is rarely used. No application shipped with RedHat Enterprise Linux calls this function, for example.All OpenSSL users should upgrade to these updated packages, which containbackported patches to resolve these issues. For the update to take effect,all services linked to the OpenSSL library must be restarted, or the systemrebooted.