9.3 - RHSA-2007:0964

Problem Description:

Updated OpenSSL packages that correct several security issues are now available for Red Hat Enterprise 5.

This update has been rated as having important security impact by the Red Hat Security Response Team.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64 RHEL Desktop Workstation (v. 5 client) - i386, x86_64 Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64

3. Problem description:

OpenSSL is a toolkit that implements Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. Datagram TLS (DTLS) is a protocol based on TLS that is capable of securing datagram transport (UDP for instance).

The OpenSSL security team discovered a flaw in DTLS support. An attacker could create a malicious client or server that could trigger a heap overflow. This is possibly exploitable to run arbitrary code, but it has not been verified (CVE-2007-5135). Note that this flaw only affects applications making use of DTLS. Red Hat does not ship any DTLS client or server applications in Red Hat Enterprise Linux.

A flaw was found in the SSL_get_shared_ciphers() utility function. An attacker could send a list of ciphers to an application that used this function and overrun a buffer with a single byte (CVE-2007-4995). Few applications make use of this vulnerable function and generally it is used only when applications are compiled for debugging.

A number of possible side-channel attacks were discovered affecting OpenSSL. A local attacker could possibly obtain RSA private keys being used on a system. In practice these attacks would be difficult to perform outside of a lab environment. This update contains backported patches designed to mitigate these issues. (CVE-2007-3108).

Users of OpenSSL should upgrade to these updated packages, which contain backported patches to resolve these issues.

Please note that the fix for the DTLS flaw involved an overhaul of the DTLS handshake processing which may introduce incompatibilities if a new client is used with an older server.

After installing this update, users are advised to either restart all services that use OpenSSL or restart their system.

4. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied.

This update is available via Red Hat Network. To use Red Hat Network, launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate RPMs being upgraded on your system.

5. Bug IDs fixed (http://bugzilla.redhat.com/):

245732 - CVE-2007-3108 RSA side-channel attack 309801 - CVE-2007-5135 openssl SSL_get_shared_ciphers() off-by-one 321191 - CVE-2007-4995 openssl dtls out of order vulnerabilitiy