[Reverse] - Bugs Bunny CTF - Rev 50

only guess

Reverse Engineering … ooh no need !

put the right password between Bugs_Bunny{…}

Author: Aymen Borgi

Starting by Executing the file:


kinyabitch@Debian ~/D/H/ctf> rev50/rev50
usage ./rev50 password

Using the ida pro to check all the strings in the program we can see there were alot of them so we can’t really guess which one is it without analysing the program itself

Checking out the main function with ida pro we can see:

We now can see where our program is checking if the flag is correct if we manage to check value of the register RAX register before that strcmp ocurrs.

I could use IDA to check those values but since is alot of trouble to do remote execute the file in a linux machine (I was executing ida in a windows VM machine) to not loose time I rather preferred to check the value on GDB:

Disassembling the main function

Identify the address and do a break point and checking the value on the register RAX

Rerunning the program with the password “mercedes”

Finally our flag is BugsBunny{mercedes}