Lendf.me Hack
What happened
Lendf.Me, dForce's Ethereum lending protocol, was drained through an ERC-777 reentrancy flaw involving imBTC. The attacker inflated recorded imBTC collateral through the token's callback behavior, then borrowed assets from more than ten liquidity pools. dForce later confirmed that all stolen assets were recovered and users were made whole.
Lendf.Me allowed a callback-capable ERC-777 token to invoke external control flow during deposit processing without comprehensive reentrancy protection. Its balance-accounting flow did not safely commit state before the token transfer interaction, enabling stale collateral values to overwrite the withdrawal result.
How it happened
The attacker interacted with Lendf.Me using imBTC, an ERC-777-compatible token. During token-transfer processing in supply(), the ERC-777 callback enabled a reentrant withdraw() before Lendf.Me finalized the user's balance update. The reentrant path withdrew collateral while the outer supply() call later wrote a stale, higher balance back to storage.
Repeating the cycle inflated the attacker's recorded collateral, allowing borrowing of the protocol's available WETH, stablecoins, BTC-related assets, and other tokens. The related April 18 Uniswap imBTC incident used the same callback family but was a separate exploit and must not be conflated with this lending-market drain.
Protocol details
Security review history
- ConsenSys Diligence View report
Funds Recovery
Recovered
$25.2M
Net Loss
$0
Evidence
Proof of concept
1 availableSources
- report Report slowmist.medium.com
- report Post-mortem medium.com
- report dForce Ecosystem Update, April 2020 medium.com
- report Lendf.Me Hack Resolution Part I medium.com
- report ConsenSys 2020 DeFi report, Lendf.me case study cognizium.io
- transaction Lendf.Me Main Attack Transaction etherscan.io
- analysis Uniswap and Lendf.Me Hacks Root Cause and Loss Analysis peckshield.medium.com
- analysis Decrypt: dForce Lendf.me DeFi hack decrypt.co
- analysis DeFiLlama defillama.com
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