Hundred Finance Hack

TOTAL LOST $7.0M
Medium Flashloan Donate Function Logic Exploit / Oracle Issue optimism

Summarize with AI

ChatGPT Perplexity Claude Grok
Affected Chain optimism Incident surface
Recovered - No recovery reported
All-Time Rank #371 By amount stolen
Auditors 1 Prior security audit

Incident Overview

Quick Summary

Hundred Finance was hacked due to a price manipulation attack, resulting in 6,701,157 $USD worth of cryptocurrency being drained from various pools.

Details of the Exploit

Hundred Finance is a multichain lending protocol. The protocol experienced a hack due to a price manipulation attack on the Optimism layer-two chain. The attacker deployed malicious smart contract with unverified source code, and then donated 200 $WBTC to inflate hWBTC's exchange rate so that even a tiny amount (2 wei) of $hWBTC could drain current lending pools.

The attacker then borrows 500 $WBTC from Aave and deposited into the pool and borrowed funds from all pools because of the inflated price of $hWBTC. Consequently, 500 $WTBC was redeemed back for nothing, which caused the attacker contract being liquidated. This resulted in 6,701,157 $USD worth of cryptocurrency being drained from their lending pools.

The hacker bridged over 1,034 $ETH valued at 2,180,000 $USD on the day of transfer along with other cryptocurrencies such as USDC and USDT via Multichain and swapped them for various tokens including DAI, FRAX, PAXG among others. 919,224 $USD worth of $sUSD and $SNX remains at the attackers original address at the moment.

Block Data Reference

Attacker address:

https://optimistic.etherscan.io/address/0x155da45d…e67528

Malicious transactions:

https://optimistic.etherscan.io/tx/0x6e9ebcde…04f451

https://optimistic.etherscan.io//tx/0x15096dc6…ceea93

Malicious contracts:

https://optimistic.etherscan.io/address/0x978d0ce2…754982

https://optimistic.etherscan.io/address/0x284abd14…5c9aac

https://optimistic.etherscan.io/address/0xd340f220…1e702b

This is classified as a Flash Loans Attacks, Oracle Manipulation & Price Manipulation . Compare similar hacks →

Incident Report

Protocol / Project Hundred Finance
Date of Incident
Affected Chain(s) optimism
Attack Technique Flashloan Donate Function Logic Exploit / Oracle Issue
Classification Protocol Logic / Borrowing and Lending
Primary Source View Post-Mortem

Protocol Information

Protocol Type Lending
Smart Contract Language Solidity
Official Website hundred.finance
Protocol Twitter/X @HundredFinance
Team Anonymous
Source Code Verified On-Chain

Market Context at Time of Hack

Token Categories
DeFi Ethereum Ecosystem Governance
Protocol Links
GitHub Discord

What the Attacker Needed to Succeed

Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.

Technical Knowledge Deep understanding of flashloan donate function logic exploit / oracle issue and Solidity and EVM internals
Capital Required Seed capital to cover gas and initial position setup
On-Chain Access Ability to interact with optimism smart contracts and deploy a custom exploit contract
Protocol Analysis Identification of the exploitable vulnerability in Hundred Finance's contract logic - root cause: protocol logic / borrowing and lending
Execution Speed Precise transaction ordering and timing to exploit the vulnerability within a single atomic block
Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Yes — skilled auditors routinely flag Flashloan Donate Function Logic Exploit / Oracle Issue vulnerabilities in code review
Audited by Audit Report 1 — still lost $7.0M. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Hundred Finance, these are the critical security checks that could have prevented this incident (April 2023).

  • Verify all logic paths related to Flashloan Donate Function Logic Exploit / Oracle Issue are guarded by proper access controls and input validation - see the Flash Loans Attacks attack class for patterns
  • Audit oracle price feeds for manipulation risks - ensure time-weighted average prices (TWAPs) or multi-source aggregators are used, not spot prices
  • Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs

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Security Audit History

Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Flash Loans Attacks examples →

Flash Loans Attacks Oracle Manipulation & Price Manipulation

Proof-of-Concept Exploits

1 PoC available
poc-exploits - hundred finance
$ HundredFinance Donate Inflation ExchangeRate && Rounding Error

On-Chain Evidence & References

Sources & References

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