In the binance hack, the attackers did not gain access to the servers themselves but rather abused API keys and other user information in order to construct and authorize a transaction that shouldn't have been authorized.
Yeah it can be the proper explanation of recent binance hack. Getting access on main server was the old entrance for hackers and now they are running after API.
It's really unexpected to hear this kinda hacking attempt news continuously. Crypto currencies are running with world's most secure technology but trading platforms are suffering the issue of hacking again and again. It's not something like that exchanges are not careful enough about their website security but hackers are using every tiny hole to reach their target.
There is no way to deny that its high time for exchanges to strengthen their entire system before getting another massive attack soon.