Analysis: Arbitrum froze KelpDAO hacker ETH as a system-level transaction, injected by the Security Committee through ArbOS

Mars Finance News, on April 21, Dragonfly Managing Partner Haseeb Qureshi released an analysis regarding “Arbitrum Security Council freezing the KelpDAO hacker’s 30,766 ETH.” He stated that this transaction type is ArbitrumUnsignedTxType (EIP-2718 type 0x65/101), which is a system-level transaction that cannot be signed by a regular EOA and can only be injected by the Arbitrum Security Council via ArbOS. This action did not carry out a chain rollback or historical rewriting; functionally, it is a state-level recovery: the attacker’s private key can still sign transactions, but the ETH at that address is transferred by the chain itself. This action also demonstrates the Security Council’s authority under “catastrophic emergencies” as described in Arbitrum’s progressive decentralization documentation.