Decoding Hopelend’s $835k Exploit

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Learn Time: 3 minutes

Abstract:

On the 18th of October 2023, HopeLend Protocol on the Ethereum chain was attacked. The assault was made potential by a Precision Loss vulnerability. Round $835k was stolen from the exploit.

About Venture:

HopeLend is a decentralized, non-custodial lending protocol. To study extra about them, try their documentation.

Vulnerability Evaluation & Affect:

On-Chain Particulars:

Attacker Deal with: 0x1F23eb80f0c16758E4A55D48097c343bD20Be56f 0xa8bbb3742f299b183190a9b079f1c0db8924145b, 0x9a9122Ef3C4B33cAe7902EDFCD5F5a486792Bc3A,

Sufferer Contract: 0xc74b72bbf904bac9fac880303922fc76a69f0bb4

Assault Transaction: 0x1a7ee0a7efc70ed7429edef069a1dd001fbff378748d91f17ab1876dc6d10392

The Root Trigger:

The basis trigger was the lack of precision loss in Htoken’s contract.

The attacker took the benefit of lack of precision in calculating liquidity index throughout execution of _handleFlashLoanRepayment

Assault Course of:

First, the attacker took a FlashLoan of 2k WBTC. adopted by including that into the Pool contract’s reserve’s liquidity index

The attacker was capable of change the liquidity index of hEthWBTC from 1e27 to 7,560,000,001e27

The attacker enhance it’s revenue by borrowing belongings from completely different markets.

This resulted in hacker profiting by paying much less collateral of WBTC attributable to precision loss

Movement of Funds:

Right here is the fund stream throughout and after the exploit. You may see extra particulars right here.

Attacker’s Wallets:

It’s price noting {that a} Generalized frontrunner 0x9a9122Ef3C4B33cAe7902EDFCD5F5a486792Bc3A was capable of frontrun the unique transaction by paying a bribe of 263ETH to one of many validatiors managed by Lido

Here’s a snippet of the pockets tackle

After the Exploit

The Venture acknowledged the hack by way of their Twitter.

Incident Timelines

Oct-18-2023 11:48:59 AM +UTC – The malicious transaction came about

Oct-18-2023 11:48:59 AM +UTC – The unique transaction was frontrunned.

How may they’ve prevented the Exploit?

It’s advocate to test all of the instances for precision loss

If potential, protocols are requested to deal with complete invariant testing

The Crucial Want for Web3 Safety

As a Web3 safety agency QuillAudits, we embrace the essence of decentralization by providing transparency, and we would like that spirit to shine by means of in our companies too.