An updated mod_cluster-native package that fixes one security issue is now available for JBoss Enterprise Web Platform 5.1.2 for Red Hat Enterprise Linux 4, 5, and 6. The Red Hat Security Response Team has rated this update as having important security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.
mod_cluster-native provides a native build of mod_cluster for the Apache HTTP Server (httpd). mod_cluster is an httpd-based load balancer. Like mod_jk, it uses a communication channel to forward requests from httpd to an application server node. It was found that mod_cluster allowed worker nodes to register on any virtual host (vhost), regardless of the security constraints applied to other vhosts. In a typical environment, there will be one vhost configured internally for worker nodes, and another configured externally for serving content. A remote attacker could use this flaw to register an attacker-controlled worker node via an external vhost that is not configured to apply security constraints, then use that worker node to serve malicious content, intercept credentials, and hijack user sessions. (CVE-2011-4608) Users of mod_cluster-native should upgrade to this updated package, which contains a backported patch to resolve this issue. Refer to the Solution section for installation instructions.