Some of you may be aware of the technique of banner grabbing to find out what software is running on a remote machine. It is done by reading out transmitted data that contains a product name and/or version, such as HTTP's "Server:" response header. Like virtually every content sent by a server, the server is totally free what to send, i.e. this can be easily faked by an HTTP server's admin, and is sometimes even done.
it security lecture
"I've always wanted to change my legal name to ;DROP DATABASE; and see what kind of havoc ensues..."
