(RHSA-2012:0070) Moderate: ruby security update

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 Walde 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.