It was discovered that the Tomcat packages installed certain configuration files read by the Tomcat initialization script as writeable to the tomcat group. A member of the group or a malicious web application deployed on Tomcat could use this flaw to escalate their privileges. A malicious web application was able to bypass a configured SecurityManager via a Tomcat utility method that was accessible to web applications. The Realm implementations did not process the supplied password if the supplied user name did not exist. This made a timing attack possible to determine valid user names. Note that the default configuration includes the LockOutRealm which makes exploitation of this vulnerability harder. When a SecurityManager is configured, a web application"s ability to read system properties should be controlled by the SecurityManager. Tomcat"s system property replacement feature for configuration files could be used by a malicious web application to bypass the SecurityManager and read system properties that should not be visible. A malicious web application was able to bypass a configured SecurityManager via manipulation of the configuration parameters for the JSP Servlet. The ResourceLinkFactory did not limit web application access to global JNDI resources to those resources explicitly linked to the web application. Therefore, it was possible for a web application to access any global JNDI resource whether an explicit ResourceLink had been configured or not