Cache cramming is a method of tricking a computer into running Java code it would not ordinarily run. The method consists of placing code in the computer's local disk cache when the computer uses Internet Explorer in certain environments.
The rogue Java code, which is a special applet (small program) known as a port scanner, is executed as a result of the computer user visiting a particular Web site designed by the cracker. When activated, the applet opens a socket connection from the cracker's computer. This can give the cracker access to data on the hard drive of the affected computer.