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Class 04 · KP 17 / 18

Tie-In: Lab 2 (Return-to-Shellcode Bonus)

  • Lab 2's bonus is a controlled, NX-disabled target so you can see the classic technique end to end.
  • Your workflow:
  • checksec the binary; confirm NX is off for the bonus target.
  • Generate shellcode (e.g., asm(shellcraft.sh())).
  • Find the offset to the saved return address.
  • Place the shellcode and overwrite the return address to jump into it (a NOP sled helps).
  • This is a historical exercise: it demonstrates why NX exists and sets up the need for ROP next.
Key Takeaway

Return-to-shellcode works only because the lab target intentionally lacks NX. Real modern targets force code reuse instead.