|
|
| import mmh3 |
| import pwn |
| from pwn import args |
|
|
|
|
| def forward_block(block): |
| """ |
| initial transformation of 4 byte block in murmurhash3 |
| """ |
| n = int.from_bytes(block, 'little') |
| n = (n * 0xcc9e2d51) & 0xffffffff |
| n = (n >> 17) | (n << 15) & 0xffffffff |
| n = (n * 0x1b873593) & 0xffffffff |
| return n.to_bytes(4, 'little') |
|
|
|
|
| def invert_block(block): |
| """ |
| invert a 4 byte block in murmurhash3 |
| """ |
| n = int.from_bytes(block, 'little') |
| n = (n * 0x56ed309b) & 0xffffffff |
| n = (n >> 15) | (n << 17) & 0xffffffff |
| n = (n * 0xdee13bb1) & 0xffffffff |
| return n.to_bytes(4, 'little') |
|
|
|
|
| def forward(blocks): |
| """ |
| forward_block applied to all 4 byte chunks |
| """ |
| return b''.join(forward_block(blocks[i:i + 4]) |
| for i in range(0, len(blocks), 4)) |
|
|
|
|
| def invert(blocks): |
| """ |
| invert applied to all 4 byte chunks |
| """ |
| return b''.join(invert_block(blocks[i:i + 4]) |
| for i in range(0, len(blocks), 4)) |
|
|
|
|
| DIFF = b'\x00\x00\x04\x00\x00\x00\x00\x80' |
|
|
|
|
| def collision8(text): |
| return invert(bytes(i ^ j for i, j in zip(DIFF, forward(text)))) |
|
|
|
|
| sample_valid_password = b'A' * 28 + b'Aa1!' |
| sample_colliding_password = collision8( |
| sample_valid_password[:8]) + sample_valid_password[8:] |
|
|
| if args["HOST"]: |
| HOST = args["HOST"] |
| if args["PORT"]: |
| PORT = args["PORT"] |
|
|
| REM = pwn.remote(HOST, PORT) |
| REM.sendline('2') |
| REM.sendline(sample_colliding_password.hex()) |
| REM.sendline('3') |
| REM.sendline(sample_valid_password.hex()) |
| REM.sendline('4') |
| print(REM.recvall().decode()) |
|
|
