In the theft report released by Binance, there is a technical detail that I don't know if you have noticed—

Through EIP-7702, the attacker bundled 50 signed authorizations into a single transaction.

Thus, after Binance suspended withdrawals, funds continued to flow out, with a single wallet losing about 167,464 ETH + $1.6 billion USDT.

Before EIP-7702, the exchange's hot wallet was an ordinary wallet (EOA): the private key is in the hands of whoever controls it. The exchange's freezing capability comes from a premise— as long as I do not sign, the money does not move.

However, EIP-7702 allows EOA to borrow smart contract code execution.

So the path is as follows:

EOA hot wallet

└── Sign a 7702 delegation once

└── Account behavior is then determined by the delegated contract code

└── The code can automatically transfer assets

└── Even if the exchange stops signing, it cannot be prevented

Now comes the industry-level question:

Binance took nearly 4 hours to discover and clear this malicious delegation; do other exchanges' custody designs also have the same problem?

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