Sonne Finance: This attack was a donation attack. We are investigating the attacker and have suspended the market.

BlockBeats news, on May 15, Sonne Finance released an attack analysis report. Sonne Finance suffered a known donation attack on the Compound v2 fork. Sonne has avoided this problem in the past by adding a market with a collateral factor of 0%, adding collateral and destroying it, and then increasing c-factors according to the proposal.

Sonne recently passed a proposal to add a VELO market to Sonne, which scheduled this transaction on a multi-signature wallet, and due to the 2-day time lock, it also scheduled the execution of c-factors within 2 days. When the 2-day time lock for creating the market ended, the attacker executed 4 of the transactions, and then executed the transaction to add c-factors to the market.

The attacker was able to exploit the protocol to obtain approximately $20 million in funds through a known donation attack. Seal contributors quickly noticed the problem and retained the remaining approximately $6.5 million by adding approximately $100 worth of VELO to the market.

Sonne is currently investigating the attacker and has suspended the market to mitigate further losses. Sonne is prepared to offer a bounty to the attacker and promises not to pursue the issue further if the attacker returns the funds.