metadata.toml

challenge_id = "no_roplem"

challenge_name = "No ROPlem"

challenge_description = '''
Sorry, I dropped all the code on the floor. You will have to put this all together again.
'''

challenge_spoilers = '''
This challenge is about building ROP chains from almost random data.
The player can input a 15 byte RC4 key. The key will be used to encrypt a one megabyte buffer of all zeroes.
After the encryption, a return instruction is inserted at every 16 bytes to make it all a little bit easier to make sure there are plenty of gadgets.
The buffer is executable (but not writable) and the address of this buffer is given to the player.
Finally, the player can input a one kilobyte ROP chain and their goal is to use all the gadgets in the large buffer to gain code execution.
One way to solve the challenge is to recreate the gadget generation algorithm and then use some basic pattern matching to look for a small set of suitable gadgets to use for the chain and apply this while iterating through random keys.
'''