I only recently learned about Fork bombs. The idea is that a user who can successfully log onto your server will run a simple program that will tell the server to run more simple programs– these programs may do nothing malicious by themselves, but when they keep creating more and more kids, your server’s resources will dwindle until the server has nothing remaining to operate with.
This VERY IMPORTANT POST about limiting user’s process/RAM Limits will help you guarantee that users will find it hard, if not impossible, to abuse the system with a fork bomb.
