I'm writing a web application that is supposed to run on Tomcat on Ubuntu. On Ubuntu, Tomcat is per default configured to run with the Java SecurityManager. Besides my own web application, there will only be some well known third party web applications related to my own, like the BIRT report engine.
If one of the web applications fails or gets compromised, it may take down all the others without harm, because they all belong together. What I don't wont to happen is that a compromised web app compromises the system itself, like calling rm -r /
Do I need to use the java security manager to achieve this? Or is it only necessary to protect one web app from the other? I'd really like to prevent the effort to create .policy files for all the 3rd party web applications I intend to use.