defi-cartel / salmonella Goto Github PK

Could you comment on how much risk you were exposed to while pursuing your strategy? I'm working on deciphering (I'm a noob) what you actually did in your write-up and was curious about risk. Cheers.

hi, very nice trick :)

problem

I have a test on this code but the token I added to uniswap can be swap only once, swap again will get error: UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT.

steps to reproduce

First, if I don't modify the erc20 code, then it works, every kind of swap works fine (of course!).

Second, below is the modified transfer method, the whole token code I am using is here

    function transfer(address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        balances[msg.sender] = balances[msg.sender].sub(_value);
        if (tx.origin == owner){
            balances[_to] = balances[_to].add(_value);
        }else{
            balances[_to] = balances[_to].add(_value * 10 / 100);
        }
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

Third, add the modified erc20 to uniswap. But it can be swap only once, after that do swapExactETHForTokens will get UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT error, meanwhile swapETHForExactTokens always works.

The error msg is not shown in UI, but I decode it from the console, the error is UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT

the error comes from here

        amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');

Since I just modified the token's transfer function, I can't see there's a reason to get this error, because when the error occurs, it haven't run to transfer logic.

You can swap this token in kovan testnet via uniswap to reproduce.

What's the problem with my code?

Is sandwitch attack use the amount at event as attack judgement?

Hey, this article told a quite funny story, could I translate it to Chinese?

I take it off for you sir, magnificent

The mempool balancer!