No eXecute

The shellcode prevention

The NX bit, which stands for No eXecute, defines areas of memory as either instructions or data. This means that your input will be stored as data, and any attempt to run it as instructions will crash the program.

To get around NX, attackers use a technique called ROP, Return-Oriented Programming.

The Windows version of NX is DEP, which stands for Data Execution Prevention

add the paramters -z execstack to gcc in order to disable the NX protection