SAN FRANCISCO – The biggest crypto hack in history began with a rehearsal.

As trading hummed along on Binance at midweek, hackers were quietly running sequences of code on accounts they controlled on the Ethereum blockchain – just a couple dollars or so at a time.

According to cybersecurity analysts, they were testing a programme designed to seize control of accounts owned by the world’s largest crypto exchange and smuggle their contents elsewhere.

Just after 4pm New York time on Oct 29, they attacked.

In short order, the infiltrators drained more than US$6 billion from wallets across at least four different blockchains, setting off a worldwide effort to contain the damage.

From New York to Abu Dhabi to Kyiv, security researchers and…