7.8 - RHSA-2012:0070

Problem Description:

Updated ruby packages that fix two security issues are now available for Red Hat Enterprise Linux 4 and 5.

The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

RHEL Desktop Workstation (v. 5 client) - i386, x86_64 Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64 Red Hat Enterprise Linux AS version 4 - i386, ia64, ppc, s390, s390x, x86_64 Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64 Red Hat Enterprise Linux Desktop version 4 - i386, x86_64 Red Hat Enterprise Linux ES version 4 - i386, ia64, x86_64 Red Hat Enterprise Linux WS version 4 - i386, ia64, x86_64

3. Description:

Ruby is an extensible, interpreted, object-oriented, scripting language. It has features to process text files and to do system management tasks.

A denial of service flaw was found in the implementation of associative arrays (hashes) in Ruby. An attacker able to supply a large number of inputs to a Ruby application (such as HTTP POST request parameters sent to a web application) that are used as keys when inserting data into an array could trigger multiple hash function collisions, making array operations take an excessive amount of CPU time. To mitigate this issue, randomization has been added to the hash function to reduce the chance of an attacker successfully causing intentional collisions. (CVE-2011-4815)

It was found that Ruby did not reinitialize the PRNG (pseudorandom number generator) after forking a child process. This could eventually lead to the PRNG returning the same result twice. An attacker keeping track of the values returned by one child process could use this flaw to predict the values the PRNG would return in other child processes (as long as the parent process persisted). (CVE-2011-3009)

Red Hat would like to thank oCERT for reporting CVE-2011-4815. oCERT acknowledges Julian Wälde and Alexander Klink as the original reporters of CVE-2011-4815.

All users of ruby are advised to upgrade to these updated packages, which contain backported patches to resolve these issues.

4. Solution:

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

This update is available via the Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at https://access.redhat.com/kb/docs/DOC-11259

5. Bugs fixed (http://bugzilla.redhat.com/):

722415 - CVE-2011-2686 CVE-2011-2705 CVE-2011-3009 ruby: Properly initialize the random number generator when forking new process 750564 - CVE-2011-4815 ruby: hash table collisions CPU usage DoS (oCERT-2011-003)