Arbitrary code execution

Arbitrary code: Code that is not ment to be executed, code that is injected into a curretly running application and thus making the application execute the code. Hence, the code is Arbitrary. It steps in. This is known, more or less as Bytecode injection.

This type of injection normally occurs thanks to Buffer Overflows with attacks such as Stack overflows Heap overflows and Integer overflows. Format string attacks will also suffice.