Incident Overview
Furucombo proxy contract was exploited, resulting in the loss of various tokens worth millions of dollars.
The attacker manipulated the Furucombo proxy contract to believe that Aave V2 had a new implementation. This new implementation had the ability to transfer all approved tokens to addresses controlled by the attacker. This was possible because users had approved the Furucombo contracts to use their tokens on their behalf.
The attacker was able to steal a variety of tokens including stETH, USDC, USDT, DAI, aWBTC, aWETH, aETH, aAAVE, WBTC, CRV, LINK, cETH, cUSDC, cWBTC, BAO, PERP, COMBO, PAID, UNIDX, GRO, and NDX. The total value of the stolen tokens is in the millions of dollars.
Attacker Address:
https://etherscan.io/address/0xb624E2b1…76B212
Malicious Transaction:
https://ethtx.info/mainnet/0x5af11a27…1ee529/
Malicious Contract Address:
https://etherscan.io/address/0x86765dde…0c4f04
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 Furucombo, these are the critical security checks that could have prevented this incident (February 2021).
- Verify all logic paths related to Delegatecall Exploit / Other are guarded by proper access controls and input validation - see the Delegatecall & Call Injection Attacks attack class for patterns
- 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 TrialSecurity Audit History
- Audit Report 1 Report
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
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