Incident reportExchange hackNEM
Coincheck −$530M
Half a billion dollars, sitting in a hot wallet.
What happened
Japanese exchange Coincheck lost 523 million NEM tokens, worth about $530 million, because they were held in an internet-connected hot wallet with a single key.
Timeline
Jan 26
NEM is drained from Coincheck's hot wallet.
Jan 28
Coincheck promises to repay affected users.
Apr 2018
Monex Group buys the exchange.
Aftermath
Coincheck repaid users in yen, and Japan tightened its rules for exchanges.
Date2018-01-26
Lost$530M
WhoUnknown at the time
Cold wallets are hard to set up.
Lesson If it's online, assume someone else can see it.