Optimism exploiter claims willingness to return 18 million OP tokens

Update (8:50 AM ET): The hacker has returned 17 million OP tokens to the Optimism Foundation in multiple onchain transactions, security firm PeckShield said.

Optimism's hacker today claimed to be open to returning 18 million Optimism (OP) tokens left with them. In an on-chain message, the unknown perpetrator offered conditionally to return the exploited tokens.

On Thursday, the hacker stole 20 million OP tokens (worth more than $30 million) after the Optimism team mistakenly transferred them to a multi-signature wallet address presumed to be controlled by Wintermute. This is a market-maker that Optimism had hired and loaned OP tokens to support the token's liquidity on exchanges.

Still, Wintermute did not have control over the address on the Optimism Layer 2 network and the perpetrator found a way to claim the tokens. Later, the hacker sold 1 million of them and sent another 1 million to an Optimism address believed to be owned by Ethereum founder Vitalik Buterin.

After the exploit, the Wintermute team had requested that the exploiter return the stolen tokens to a specific return address, and offered assurances that no legal action would be taken if this was done.

Optimism hacker's on-chain message to Vitalik Buterin (source: Etherscan)

In the on-chain message to Vitalik on Friday, the hacker offered to make the transfer, but on the condition that Buterin make the first move and transfer the 1 million OP tokens he had been sent in order to verify the genuineness of the return address.