[HN Gopher] Attacking the DeFi ecosystem with flash loans for fu...
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       Attacking the DeFi ecosystem with flash loans for fun and profit
        
       Author : lawrenceyan
       Score  : 43 points
       Date   : 2021-01-16 21:22 UTC (1 hours ago)
        
 (HTM) web link (arxiv.org)
 (TXT) w3m dump (arxiv.org)
        
       | paulpauper wrote:
       | the problem with defi hacks, from the perspective of the hacker,
       | is you get a bunch of eth, which is a lot harder to hide and
       | launder than BTC. As the saying goes, in crypto, your wallet is
       | the bug bounty.
        
         | code-is-code wrote:
         | Do you really have to launder them? I mean, you do as the smart
         | contract says, it might not even be illegal.
        
           | VectorLock wrote:
           | Everybody thinks "we don't need laws, we let the smart
           | contracts handle it" until their smart contract is exploited
           | and their funds "robbed."
        
             | Nextgrid wrote:
             | Have any of the smart contract exploits actually been
             | litigated in court, even if unsuccessfully?
        
         | Vinceo wrote:
         | Why is it harder to launder eth? You can just exchange them to
         | monero on a non KYC exchange.
        
           | paulpauper wrote:
           | KYC exchanges don't really exist anymore because they were
           | abused in 2017 and thus either forced to close or comply with
           | regulation (such as the wannacry ransomware virus, in which
           | the criminals laundered their BTC into monero on shapeshift,
           | which at the time had no KYC). Second, cross-chain exchanges
           | may not be possible in a fully trustless manner.
        
             | Acrobatic_Road wrote:
             | wrong and wrong of course.
             | 
             | Shapeshift just DROPPED its KYC.
             | 
             | https://erikvoorhees.medium.com/no-more-kyc-with-
             | shapeshift-...
             | 
             | >Second, cross-chain exchanges may not be possible in a
             | fully trustless manner.
             | 
             | Monero <-> Bitcoin atomic swaps (codename: farcaster) are
             | coming later this year. In the mean time, you can use Bisq.
        
         | CyberDildonics wrote:
         | Why would it be harder to launder? The average bitcoin
         | transaction is up to 17 USD, even combining addresses or
         | tumbling is going to eat into your balance.
        
           | paulpauper wrote:
           | eth uses an accounts model instead of the UTX model for
           | transactions. Tis makes it much, much easier to trace payment
           | flows.
        
         | phyalow wrote:
         | Fairly straightforward in Ethereum to break a audit trail via
         | services like tornado.cash etc.
        
       | v64 wrote:
       | Flash loans are a great example of how blockchains enable new
       | types of financial transactions that either aren't possible or
       | are very difficult to do in a traditional financial setting.
       | 
       | If you identify an arbitrage opportunity in the market, you can
       | atomically borrow a large sum of money to take advantage of the
       | price difference. You also have the added assurance that if the
       | arbitrage opportunity goes away before you can take advantage of
       | it, the entire transaction fails and you only lose the Ethereum
       | transaction fee. It's essentially risk-free arbitrage.
       | 
       | This paper [1] dives into detail about how these arbitrage
       | mechanics play out on the blockchain, and how both arbitrageurs
       | and miners manipulate transactions in order to make a profit.
       | 
       | [1] https://arxiv.org/abs/1904.05234
        
       | qqii wrote:
       | Personally I found this article much clearer than the paper:
       | https://www.palkeo.com/en/projets/ethereum/bzx.html
       | 
       | You can actually follow the money yourself:
       | 
       | https://etherscan.io/address/0x148426fdc4c8a51b96b4bed827907...
       | https://etherscan.io/address/0xb8C6Ad5fE7CB6cC72F2C4196dca11...
       | 
       | It looks like neither attacker was able to cash out, but the
       | seccond attacker is moving his funds around even to this day.
        
       | Acrobatic_Road wrote:
       | Ethereum is like a real world PVP system fought with real money.
       | And I wouldn't have it any other way.
        
         | dylkil wrote:
         | Its more like PvE system
        
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       (page generated 2021-01-16 23:00 UTC)