In connection with the last Ddos-attak on the EXMO exchange (the official response of the exchange), it is a question of time who will be the next target.
You're asking questions that its like we are nostradamus or we are those bastards that will attack a website for ddos.
There are lots of paid tools/services that fights for it, tho it cannot prevent from happening at least it minimize its damage.
If you're worried of who will be the next target exchange of hack or ddos. Then probably you should diversify your trading funds to at least 3 trusted exchange.
Or if you are worried about such scenario happening to the exchange you are using, better use binance as they have insurance for their traders. So even if they are hacked or something, you know, you can still get your coins. Because no one here can tell you which exchange is next. Because even these top exchanges are vulnerable to those attacks. Hackers are getting a hold of more sophisticated softwares nowadays, so it is not surprising if one day, one of them will be hacked.