SynopsisThe remote Scientific Linux host is missing one or more security updates.
DescriptionCVE-2009-3555 TLS: MITM attacks via session renegotiation
CVE-2010-0731 gnutls: gnutls_x509_crt_get_serial incorrect serial decoding from ASN1 (BE64) [GNUTLS-SA-2010-1]
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:
Dan Kaminsky found that browsers could accept certificates with MD2 hash signatures, even though MD2 is no longer considered a cryptographically strong algorithm. This could make it easier for an attacker to create a malicious certificate that would be treated as trusted by a browser. GnuTLS now disables the use of the MD2 algorithm inside signatures by default. (CVE-2009-2409) SL5 Only
A flaw was found in the way GnuTLS extracted serial numbers from X.509 certificates. On 64-bit big endian platforms, this flaw could cause the certificate revocation list (CRL) check to be bypassed; cause various GnuTLS utilities to crash; or, possibly, execute arbitrary code. (CVE-2010-0731) SL4 Only
For the update to take effect, all applications linked to the GnuTLS library must be restarted, or the system rebooted.
SolutionUpdate the affected gnutls, gnutls-devel and / or gnutls-utils packages.