Analysis: Arbitrum Freezes KelpDAO Hacker's ETH with System-Level Transaction, Injected via ArbOS by Security Council

BlockBeats News, April 21st, Dragonfly partner Haseeb Qureshi released an analysis regarding the "Arbitrum Security Council Freezes 30,766 ETH Stolen by KelpDAO Hacker." He stated that the transaction type was 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 into ArbOS by the Arbitrum Security Council. This operation did not involve any chain rollback or historical rewriting; functionally, it was a state-level recovery where the attacker's private key can still sign transactions, but the ETH from that address was moved by the chain itself. This operation also showcased the Security Council's power in a "catastrophic emergency" as described in the Arbitrum Progressive Decentralization documentation.