The individual or group behind the alleged Tether attack may have been involved in a previous well-known hack in the bitcoin space.
Analysts reacted positively to news that exchange Bitfinex had redeemed roughly 1% of its outstanding debt tokens on 1st September.
Bitcoin prices fell sharply on 2nd August, extending declines as markets responded to news that a major exchange had been hacked.
Withdrawals are once again live on Poloniex after it lost 12.3% of its bitcoins to hackers.
Binance has suspended trading and withdrawals amid a site upgrade.
A South Korean bitcoin exchange is moving to declare bankruptcy following what it said was a debilitating cyber attack.
Bitfinex has announced it has bought back all outstanding investor liabilities resulting from a hack on its platform nearly six months ago.
Digital currency exchange ShapeShift says it now believes that a hacking incident announced last week involved a former employee.
Digital currency exchange service ShapeShift is offline after a security incident earlier this week.
Bitcoin exchange Cointrader has announced that it is shutting down following what it claimed was a debilitating hack.