CSAW CTF 2013 - Exploitation100

Exploitation 1 - 100 Points
exploit1
exploit1.c

We were give an elf32 executable and its code snippet of its handle() function in this challenge:

Our objective is to change the backdoor value to 1, so that the key to this challenge will be read and sent back to us.

buffer[] array is defined to have size of 1016. However in recv(), it is shown that 1020-byte of data will be copied into buffer[], classic case of buffer overflow. So we did what came naturally:

$ python -c "print 'A'*1020" | nc 128.238.66.212 31337

Voila!