Buffer Overflow Attack explanied

A buffer overflow occurs when a program or  process attempts to write more data to a fixed length block of memory, or buffer , than the buffer is allocated to hold. Since buffers are created to contain a defined amount of data, the extra data can overwrite data values in memory addresses adjacent to the destination buffer unless the program includes sufficient bounds checking to flag or discard data when too much is sent to a memory buffer.

Making yourself the all-powerful "Root" super-user on a computer using a buffer overflow attack.