Scientific Linux Security Update : openssl on SL5.x i386/x86_64
Critical Nessus Plugin ID 60759
SynopsisThe remote Scientific Linux host is missing one or more security updates.
DescriptionCVE-2009-3555 TLS: MITM attacks via session renegotiation
CVE-2010-0433 openssl: crash caused by a missing krb5_sname_to_principal() return value check
CVE-2009-3245 openssl: missing bn_wexpand return value checks
It was discovered that OpenSSL did not always check the return value of the bn_wexpand() function. An attacker able to trigger a memory allocation failure in that function could cause an application using the OpenSSL library to crash or, possibly, execute arbitrary code.
A flaw was found in the way the TLS/SSL (Transport Layer Security/Secure Sockets Layer) protocols handled session renegotiation. A man-in-the-middle attacker could use this flaw to prefix arbitrary plain text to a client's session (for example, an HTTPS connection to a website). This could force the server to process an attacker's request as if authenticated using the victim's credentials. This update addresses this flaw by implementing the TLS Renegotiation Indication Extension, as defined in RFC 5746.
Refer to the following Knowledgebase article for additional details about the CVE-2009-3555 flaw:
A missing return value check flaw was discovered in OpenSSL, that could possibly cause OpenSSL to call a Kerberos library function with invalid arguments, resulting in a NULL pointer dereference crash in the MIT Kerberos library. In certain configurations, a remote attacker could use this flaw to crash a TLS/SSL server using OpenSSL by requesting Kerberos cipher suites during the TLS handshake.
For the update to take effect, all services linked to the OpenSSL library must be restarted, or the system rebooted.
SolutionUpdate the affected openssl, openssl-devel and / or openssl-perl packages.