In a single withdrawal, hackers syphoned US$40 million (NZ$60m) in bitcoin from one of the largest cryptocurrency exchanges in the world.
Binance said it would suspend all deposits and withdrawals for at least a week while it conducts a security review - a move that affects 6 million users - although trading will continue. The company said that thieves employed phishing and viruses to commandeer the 7,000 bitcoin, and that hackers might still control some user accounts.
The heist builds on the explosive growth in cryptocurrency crime and investor scams, which increased more than 400 per cent in 2018 and added up to about US$1.7 billion in losses, according to the cybersecurity firm CipherTrace. More than half that total, or US$950 million, was taken from exchanges such as Binance and wallets that allow people to store digital currencies.
Many people are drawn to bitcoin because they can make transactions anonymously. Though the trades are recorded in public transactions, individual account holders are not personally identifiable, a key reason the cryptocurrency is so appealing to criminals. Law enforcement agencies do have ways of tracking stolen bitcoin, however, including tying a person's known IP address to their bitcoin transactions and tracing how hackers exchange large amounts of bitcoin into hard currency.
Binance said the theft affected one of its Internet-connected wallets, which contained about 2 per cent of its total bitcoin holdings. The company said that no user money will be affected and that insurance will cover the losses in full.