CVE-2009-3548: Apache Tomcat Windows Installer insecure default administrative password
Vendor: The Apache Software Foundation
Versions Affected: Tomcat 5.5.0 to 5.5.28 Tomcat 6.0.0 to 6.0.20
The unsupported Tomcat 3.x, 4.0.x, 4.1.x and 5.0.x versions may be also affected.
Description: The Windows installer defaults to a blank password for the administrative user. If this is not changed during the install process, then by default a user is created with the name admin, roles admin and manager and a blank password.
Mitigation: Users of all Tomcat versions may mitigate this issue by one of the following methods: - Using the .zip or .tar.gz distributions - Specifying a strong password for the admin user when using the Windows installer - Removing the admin user from the tomcat-users.xml file after the Windows installer has completed - Editing the tomcat-users.xml file to provide the admin user with a strong password after the Windows installer has completed
A patch for this issue  has been applied to trunk and will be included in the next releases of 6.0.x and 5.5.x
Credit: This issue was reported directly  to the tomcat users public mailing list by David Horheim. Security researchers are reminded that undisclosed vulnerabilities in Apache Tomcat should, in the first instance, be reported to the private security mailing list. 
References:  http://svn.apache.org/viewvc?view=revision&revision=834047  http://markmail.org/thread/wfu4nff5chvkb6xp  http://tomcat.apache.org/security.html