Incident Overview
A Goldfinch Finance user (deltatiger.eth) was attacked through a vulnerability in an old contract on Ethereum, resulting in approximately $330,000 loss. The attacker exploited the collectInterestRepayment() function to drain USDC from approved addresses and manipulate sharePrice, with 118 ETH already laundered through Tornado Cash.
The attacker exploited a vulnerability in the collectInterestRepayment() function of an old Goldfinch contract, which allowed unauthorized transfer of USDC from any address that had granted approval to the contract. By artificially inflating the sharePrice, the attacker deposited only 1,000 USDC but was able to repeatedly withdraw funds due to the manipulated sharePrice calculation. The exploit targeted users who had previously approved the vulnerable contract, allowing the attacker to drain their USDC holdings without their direct interaction.
Victim:
https://etherscan.io/address/0x526C7665…1e431d
Exploiter:
https://etherscan.io/address/0x2c2ec355…9c1ee9
Exploit tx:
https://etherscan.io/tx/0x3a8bde0a…f751c2
Incident Report
Protocol Information
Market Context at Time of Hack
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 Goldfinch Finance, these are the critical security checks that could have prevented this incident (December 2025).
- Verify all logic paths related to Other are guarded by proper access controls and input validation
- 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 TrialSources & References
Learn to Prevent the Next Goldfinch Finance
The Goldfinch Finance hack is one of many attacks that skilled auditors are trained to detect before deployment. Master real exploit patterns and defense techniques with hands-on Web3 security training.