Theft of 523 million units of the cryptocurrency XEM belonging to 260,000 customers by anonymous hackers.
Coincheck said the stolen funds were stored in a “hot wallet”. A hot wallet is a computer connected to the internet and thus accessible to a hacker.
Best practice in the industry is to keep most funds in a “cold wallet” held offline.
The timeline shows attacker was a registered customer. The NEM foundation has tagged the stolen cryptocoins, like stolen bank notes with serial numbers. So exchanges can tell if the hacker tries to upload the stolen coins. page 
FRIDAY JANUARY 26 (TOKYO) - 00.02AM Unidentified hacker sends 10 XEM, worth about $10, from Coincheck to their own traceable wallet - 00:10AM Having penetrated the company’s security and found a fortune in XEM sitting in a “hot wallet”, the hacker then executes six separate transactions over an eight-minute period and steals 520m XEM, worth roughly $500m - 03:00AM The hacker starts sending the coins on to other digital wallets - 03:35AM Another 1.5m coins are taken - 04:33AM A further 1m XEMs are taken from the Coincheck vaults - 08:26AM The final 800,000 XEMs are removed - 11:25AM Coincheck discovers the theft and raises the alarm
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## “They always talked about security. But that was just talk.”
“I totally believed in Coincheck. I trusted it,” says Ms Yamazaki. page