It's not been unusual from time to time to hear about a bitcoin exchange being under DDoS attack here and there, but over the past few weeks, it seems many exchanges have come under attack. There seems to be some coordinated attack on bitcoin exchanges going on, knocking many offline, with a few over just the past 24-48 hours. We've heard of the bigger ones in the past, such as Kraken and OKCoin. There other ones that are happening too. Some are for ransom. Some aren't saying, they just say DDoS... maybe the attackers if successful, then move on to extort, not sure. But something is going on and exchanges are the target.
Yesterday BitBargain was under attack:
exchanges/uk-bitcoin-exchange-bitbargai ... t2676.html
Today Bitcoin Thailand and The Rock Trading...
https://twitter.com/BitcoinThai/status/ ... 6464559104
https://twitter.com/TheRockTrading/stat ... 9318414337