I would say hackers are everywhere and they can not stop running the crypto currencies because they know very it's anonymous nature is leading factor for them. They kind of get extra layer of protection. Anyway with some research they can be caught.
About the precautions . .
1. You should store your tokens and/or coins in the wallet for which you hold the private keys.
2. Obviously store these private keys in safe place and I would suggest that you should save them in the offline password manager.
3. Never ever go to link of your wallet from different websites, chats etc. Always bookmark your wallet website link.
4. Using the hardware wallet is advisable but looking at the cost you may prefer focusing on the first three points.
5. Storing the tokens on exchanger is worst idea. Hence follow the rules 1, 2 & 3.
5. Do not use public internet and I am pretty sure if you access wallets like that then you will loose your money.
That's all I know and I follow.
Yeah you are right...the online bitcoin wallets is have a chance for hackers
Bitcoin is impossible to steal... only require more effort of it.
In cyber security report cryptojacking remains in acute threat in 2018