Lending Protocol: Vectors of Attack and Preventing Potential Issues

Andrii Stepanov
Marketing Manager
4 Minutes Read

The Decentralized Finance (DeFi) ecosystem has become a transformative force within the digital finance world. At the forefront of DeFi innovation are lending protocols, offering revolutionary means of borrowing and lending without traditional intermediaries. These protocols primarily function through a mechanism of collateral-backed loans, dynamic interest rates, and automated liquidation events. Yet, their groundbreaking capabilities are not without challenges. 2023 alone has unveiled multiple vulnerabilities, with prominent lending protocols falling victim to sizable hacks.

The most recent case of lending protocol exploitation was on March 13, 2023, when Euler Finance, a lending protocol on Ethereum blockchain, was hacked for over $197 million. The attacker exploited a vulnerability in the protocol’s borrowing and liquidation mechanisms to completely drain DAI, USDC, WETH, and other token pools.

Such events underscore the importance of understanding the multiple vectors through which these protocols can be compromised.

Vectors of Attack on Lending Protocols

Oracle Manipulation

Oracles play a vital role by acting as bridges between the blockchain and the external world, importing data that is necessary for various smart contract functions. But they are also a common point of vulnerability. Attackers can manipulate oracles by feeding them erroneous data. This might be done by either directly compromising the oracle’s data sources or by exerting market pressure in places the oracle derives its data from. This false data can lead to wrongful liquidations, inaccurate interest rate calculations, or other unintended financial outcomes, putting user funds at significant risk.

Economic Attacks

  • Flash Loan Attacks: flash loans allow users to borrow vast sums of money without collateral, under the condition it’s returned within the same transaction. Attackers use this sudden capital to manipulate market conditions in their favor. By inducing artificial volatility or price discrepancies, they can profit off of arbitrage or other financial mechanisms before promptly returning the loan, often leaving protocols and users at a loss.
  • Liquidity Attacks: By artificially manipulating the liquidity in these pools, attackers can influence loan value and liquidation thresholds. This might be achieved by sudden withdrawals, depositing malicious tokens, or exploiting pool creation mechanisms. Such manipulations can significantly destabilize a protocol and cause losses for lenders or borrowers.

Sybil Attacks and Collusion

  • In a Sybil attack, one actor spawns multiple pseudonymous identities, aiming to subvert the network’s inherent trust system. Collusion, on the other hand, involves multiple actors or entities working covertly to achieve a particular outcome. Within lending protocols, this could lead to undue influence on governance decisions, misrepresentation in borrowing/lending, or even distortions in interest rate calculations.

    Peg Failures

  • They maintain their value by being pegged to stable assets, commonly the US dollar. However, if external market pressures, governance failures, or collateralization issues cause a stablecoin to lose its peg, it can result in significant cascading effects. Lending protocols relying on that stablecoin might see drastic imbalances in loan-to-value ratios, triggering a wave of unintended liquidations. This could also erode trust in the protocol, leading to rapid withdrawals and potential solvency issues

Preventing Potential Issues

In the rapidly evolving world of Decentralized Finance (DeFi), securing lending protocols becomes paramount. Here’s how the industry is progressing to shield itself against vulnerabilities:

Comprehensive Auditing

Before launching any protocol into the wild, it’s crucial to subject its code to rigorous scrutiny. Conducting multiple in-depth audits from reputable firms ensures that various perspectives evaluate the code for vulnerabilities. Post-launch audits are equally important, given that live environments might expose issues that theoretical checks missed.

Decentralized and Secure Oracle Systems

Given the vulnerabilities tied to oracles, diversifying data sources is vital. Decentralized oracles, which aggregate data from multiple sources, reduce the risk of manipulation. By ensuring no single point of failure, protocols can trust the data they operate on more confidently.

Rate Limiting and Delay Mechanisms

Flash loan attacks have underscored the need for safeguards. By placing limits on how frequently certain contract functions can be called and introducing time delays for substantial contract changes, protocols can effectively nullify the rapid actions that flash loan attacks rely on.

Insurance and Coverage

Even with the best safeguards, there’s always some residual risk. Integrating with established DeFi insurance protocols or creating dedicated internal insurance pools can provide a safety net. This ensures that users are compensated and retained, even in the unfortunate event of a security breach.

Bug Bounty Platform

Harnessing the collective intelligence of the global ethical hacking community can be invaluable. By setting up bug bounty programs, protocols can encourage continuous and crowdsourced vulnerability assessments. Ethical hackers, in their pursuit of bounties, can expose weaknesses that might be overlooked even by comprehensive audits, ensuring that protocols remain robust and secure over time.


The DeFi space, while lucrative and revolutionary, is fraught with challenges. But with the meticulous implementation of the above preventative measures, lending protocols can significantly insulate themselves from potential threats, ensuring a safer financial ecosystem for all participants.

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