Incident Overview
An attacker exploited a vulnerability in the FARM_USDT and FARM_USDC pools, stealing $33.8 million through a series of flash loans and price manipulation.
The attacker initiated the exploit by swapping 11.4 million USDC for USDT, causing the price of USDT to rise. They then deposited 60.6 million USDT into the Vault. Following this, they exchanged 11.4 million USDT back to USDC, causing the USDT price to drop. The attacker then withdrew 61.1 million USDT from the Vault, making a profit of 0.5 million. This process was repeated 32 times. The stolen funds were then converted to renBTC and exited to BTC / ETH via Tornado Cash.
Stolen funds:
- $33.8M USDT
The attacker's address:
https://app.zerion.io/0x3811765a…5f119b/history
The transaction behind the attack:
https://etherscan.io/tx/0x9d093325…7a2dc1/advanced
Detailed transaction analysis:
https://ethtx.info/mainnet/0x9d093325…7a2dc1
Incident Report
Protocol Information
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.
What Auditors Should Check
If you're auditing a protocol with similar architecture to Harvest Finance, these are the critical security checks that could have prevented this incident (October 2020).
- Verify all logic paths related to Flashloan Price Oracle Attack / Flash Loan Attack 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
Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.
Free TrialFunds Recovery
Recovered
$2.5M
Net Loss
31298799
Security Audit History
- Audit Report 1 Report
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Proof-of-Concept Exploits
On-Chain Evidence & References
- Reference https://rekt.news/harvest-finance-rekt/
- Block Explorer https://etherscan.io/tx/0x35f8d2f572fceaac9288e5d462117850ef2694…
Sources & References
- 01
- 02
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