Offchain Labs exposes two serious vulnerabilities in the OP Stack fraud proof

ChainCatcher news, according to official sources, the Arbitrum development team Offchain Labs announced on March 22 that they disclosed two serious security vulnerabilities found in the Optimism testnet to the OP Labs team. These vulnerabilities exist in the Optimism fraud proof system deployed by OP Labs. Offchain Labs provided a demonstration exploit code to the OP Labs team.

On March 25, OP Labs confirmed the validity of these two issues, and both parties coordinated the vulnerability disclosure timeline. OP Labs requested Offchain Labs to temporarily refrain from publicly disclosing these vulnerabilities until they are resolved. Later yesterday (April 25), the Optimism testnet was updated, and today Offchain Labs disclosed these vulnerabilities for the first time.

These vulnerabilities allow malicious parties to force the OP Stack fraud proof mechanism to accept fraudulent chain history or to prevent the OP Stack fraud proof mechanism from accepting the correct chain history. These issues stem from flaws in the OP fraud proof design regarding timer handling.