Over the weekend, crypto exchange Coinrail tweeted that it was hacked, and noted that lesser-known cryptocurrencies such as Pundi X were among those affected, according to Google Translate. The Pundi X-bitcoin pair is the most-traded on Coinrail, CoinMarketCap data showed. However, Coinrail's public statements did not mention bitcoin, according to Google Translate. Nevertheless, Bitcoin hit a low of $6,647.33 on Sunday, its lowest since April 9, according to CoinDesk's bitcoin price index, and coincided with a broader crypto sell-off. The digital currency traded off those lows Monday morning, near $6,774.