Shellcode - Platforms

Platforms

Most shellcode is written in machine code because of the low level at which the vulnerability being exploited gives an attacker access to the process. Shellcode is therefore often created to target one specific combination of processor, operating system and service pack, called a platform. For some exploits, due to the constraints put on the shellcode by the target process, a very specific shellcode must be created. However, it is not impossible for one shellcode to work for multiple exploits, service packs, operating systems and even processors. Such versatility is commonly achieved by creating multiple versions of the shellcode that target the various platforms and creating a header that branches to the correct version for the platform the code is running on. When executed, the code behaves differently for different platforms and executes the right part of the shellcode for the platform it is running on.