Yes. That's something bad happening in the crypto world. Indeed, many hackers try to attack blockchain security systems. But it is very rare for those who succeed. But most of the ones they managed to attack were exchange security systems. This time they tried to hack into PolyNetwork's security system, and they managed to break through. And bring bad impact for PolyNetwork.
With such an incident (security system hacking), it should be a lesson for anyone to always be aware of the account security system.
Because account security is very important in all areas of work.