Flash loans in Decentralized Finance - PerfectionGeeks

Understanding Flash Loans in DeFi

April 28, 2022 01:00 PM

Flash loans in DeFi

If you want to borrow money from traditional banks, you will need to provide various documents, such as a formal ID and proof of income. A flash loan does not require any of these documents. These loans are instantaneous so that users can get funds quickly. Many argue that flash loans are very useful and innovative in cryptocurrency. However, cybercriminals can also exploit them to take advantage of protocols that are not well protected.

Let's dive deeper into flash loans to find out who is lending them and the risks.

What is a DeFi Flash loan?

The flash loan is a relatively new type of uncollateralized loan that traders can access using some Decentralized Finance (DeFi) protocols based on an Ethereum Blockchain Network (Ethereum).

This loan type allows traders to borrow unsecured loans directly from the lender without intermediaries. Because flash loans allow users to trade and arbitrage in new ways, they have become very popular.

What makes Flash Loans so unique?

We are all familiar with the concept of flash loans. Lenders lend money to borrowers, and then they are paid back with some or no profit. The DeFi Flash Loan transaction looks similar, but flash loans have unique properties that make them more appealing to both the borrower and the lender.

Smart Contracts

Smart contracts are flash loans. This feature is part of blockchain technology. It prevents funds from leaving one account without fulfilling certain obligations. The smart contract rules ensure that the borrower repays the loan after a flash loan is issued. The smart contract will reverse the transaction if this condition is not met.

This ensures the safety of funds in the reverse pool.

Unsecured Loans

Traditional lending requires that borrowers have collateral swaps and arbitrage to lend money. If the borrower fails to pay the loan terms, the lender can still recover the collateral. An unsecured loan does not mean that the lender won't receive their money back if things go wrong. They will get it back in another way.

Instantaneous Transactions

There are many steps involved in obtaining a loan. A person approved for a loan will likely repay it by depositing a certain amount over some time. The process of getting a flash loan in decentralized finance protocols is instantaneous. The DeFi flash loan process has three steps:

  • You receive the loan.
  • You use the loan to produce.
  • You pay back the loan.

This may seem not very easy for beginners, so let's simplify it. You can ask a lender for a quick loan of $50,000 in ETHLENDER. After they approve you, you will have $50,000 in borrowed capital available for trade. However, you must repay the loan within the same transaction. This usually takes only a few seconds. Although it may sound strange, this is because we have modified our thinking to work with traditional transactional methods. You should note that the smart contract transaction can be reversed if you are unable or unable to repay the loan.

Where can you get Flash Loans?

Although flash loans are becoming more popular in crypto, they are unavailable for traders on all trading platforms. These are some flash loans in DeFi platforms that offer flash loans to traders:


Aave is the leader in flash loans. Aave flash loans can be used by Defi traders using Aave V2 to swap and migrate positions. These loans are a great option due to:

They can arbitrage among assets without having the principal amount required to execute an arbitrage.

  • They permit the swapping of collateral for loan positions without paying the loan debt. Other DeFi Flash loan platforms:
  • DyDx
  • Decentralized Exchange (DEX).
  • Uniswap

Why would you use a flash loan?

Flash loans allow traders to profit while not putting their money at risk. You can use them for the following:

Arbitrage opportunities

Traders use flash loan transactions to profit from price discrepancies between price exchanges. They also exploit time. A trader may use a flash loan and separate smart contracts to buy tokens on one exchange for $2,000 and then sell them on the other exchange for $2,500. This generates a $500 profit. The trader then repays the loan and keeps the profits.

Collateral Swaps
  • This is where one collateral is used to replace the other to secure the loan.
  • Transaction fees reduced
  • The service fee for a flash loan is lower because it combines multiple transactions into one (in certain cases). So the borrower pays lower fees, and the transaction cost is charged to the loan amount.

Flash Loan Transactions Are Risky

Over the years, there have been numerous attacks on flash loans that have led to millions of dollars in losses for vulnerable Defi protocols. As malicious actors continue to exploit the loaning system in various ways, the technology behind Defi and the Ethereum network could be improved.

Hackers can exploit loopholes in smart contracts that aren't always constructed correctly. Sometimes the data received can be an inaccurate or unsecured loan. This makes smart contracts vulnerable to hackers, who may steal millions of dollars in loan capital.

What is a Flash Loan Attack?

Flash loan attacks, a form of DeFi attack, are where cyber thieves take out loans from lending protocols to manipulate the market. They exploit smart contract vulnerabilities to cheat another party or introduce unwelcome modifications to the smart contract's code. These are the most popular type of DeFi apps development attacks because they are easy to commit. They've also become more common in recent years, with several high-profile attacks appearing in the media.

Flash loans, as mentioned above, allow users to borrow large amounts on various exchanges even if they have zero capital. Although the loan is instantaneous, you will need to use the borrowed funds to repay them.

Flash loan attackers can borrow large amounts of money because decentralized lenders don't require collateral. They can manipulate crypto-asset funds and resell them on other exchanges.

The most frustrating thing about the attack is that they can manipulate the market and still follow the rules. They can also do it multiple times without leaving any trace and steal millions of dollars.

Flash Loan Attacks: well-known examples

Recent flash loan attacks seem to be on the rise. These are just a few examples of high-profile attacks that illustrate how easy it is to perpetuate these attacks.

dYdX: In the case of the dYdX Flash Loan Attack in early 2020, an attacker used the platform to obtain the loan. He then divided the loan income and used it on Compound and Fulcrum lending platforms. Fulcrum was forced to purchase WBTC because Fulcrum used the first portion of the loan to shorten ETH. Fulcrum ordered WBTC through Uniswap. However, due to Uniswap's low liquidity, the price of WBTC soared significantly. Fulcrum, therefore, had to pay more.

The attacker used the remainder of the dYdX loan to take out a WBTC loan via Compound. The attacker borrowed WBTC and flipped it on Uniswap to make profits. The attacker then paid off their loan to dYdX and took the rest of the ETH.

Pancake Bunny: Pancake Bunny’s most recent flash loan attack occurred in May 2021. An exploit caused Pancake Bunny’s token to drop 95% from its original value. Pancake Swap borrowed many BNBs to manipulate Pancake Bunny’s pools' prices. The price of BUNNY crashed after a large amount was stolen and then dumped onto the market.

CREAM Finance: This protocol was also attacked several times in 2021. The largest heist involved $130 million. They used multiple flash loans to manipulate the price of the oracle. They could get away with CREAM liquidity tokens worth millions of dollars.

Flash Loan Attacks: Can you stop them?

Flash loan attacks remain frustratingly common in DeFi wallets so it is obvious that there are no one-size-fits-all solutions. There are, however, steps you can take to prevent them.

Prices oracles

Flash Loans are often viewed as a vulnerability in DeFi. Flash loan attacks are just attacks on Oracles. Third-party services such as ChainLink and WitNet that connect smart contracts to the noncustodial decentralized wallets world include Provable, WitNet, and WitNet, all blockchain oracles. They allow you to securely transfer off-chain data into a blockchain network's On-chain environment.

Top Defi protocols use decentralized networks with oracles to account for liquidity and volume differences across multiple exchanges. They are therefore more resistant to flash loan-funded manipulation.

Security platforms DeFi

The delay in the response time of DeFi platform developers is a key factor that allows cyber thieves to execute flash loans. Open Zeppelin Defender is the most popular security platform.

Open Zeppelin Defender enables project managers to spot smart contract development exploits and unusual activities. This allows them to react much quicker and take immediate action to stop the attacks. You might also find our article interesting on why security audits no longer work for DeFi.

A turning tide for Flash Loan attacks

Flash Loans are an important tool in DeFi. Although they are vulnerable to many attacks, the tide is changing. These attacks will likely decrease with more thorough research, improved security tools, and the use of pricing oracles.

Flash Loans are still in their infancy, and many of their potential uses are not yet fully explored. Others believe they will be used to fund innovative projects, such as buying tokens and borrowing money to finance governance votes. Contact PerfectionGeeks Technologies, as we keep you updated with the latest trends and technologies. Flash Loans have a lot of future potential, so let's keep an eye on this.

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Contact US!

India india

Plot No- 309-310, Phase IV, Udyog Vihar, Sector 18, Gurugram, Haryana 122022

+91 8920947884


1968 S. Coast Hwy, Laguna Beach, CA 92651, United States

+1 9176282062

Singapore singapore

10 Anson Road, #33-01, International Plaza, Singapore, Singapore 079903

+ 6590163053