https://www.reuters.com/article/us-markets-bitcoin-korea/south-korean-exchange-coinrail-says-hit-by-hackers-bitcoin-slides-idUSKBN1J703I >South Korean cryptocurrency exchange Coinrail said it was hacked over the weekend, prompting an extended sell-off of bitcoin to a 2-month low amid growing concerns about security at small- to mid-sized virtual currency exchanges.