Letssplitturtles.part02.rar
This write-up covers the second part of the challenge from CSAW CTF, focusing on the exploitation of a recursive data structure to achieve code execution. Challenge Overview
: By placing a magic_gadget address at a specific offset ( +0x60 ), the program was forced to execute the desired shellcode or function when it attempted to traverse to the "next" turtle. Execution & Debugging LetsSplitTurtles.part02.rar
The core of this stage involved crafting a precision payload that aligned with the program's expectations of the turtle structure while redirecting the instruction pointer. This write-up covers the second part of the
: A 64-byte ( 0x40 ) buffer of null bytes provided a safe landing zone for the program's internal processing. : A 64-byte ( 0x40 ) buffer of
: The payload specifically targeted RDX and RAX to set up the final call.
: Using the leak obtained previously, the payload had to account for specific register offsets. Payload Structure :
The exploit was verified using to step through the turtle traversal logic. A critical finding during this phase was that the RBP (Base Pointer) register did not land at the expected offset, requiring a slight adjustment to the slack space to ensure the magic gadget was reached successfully.