Whatsapp has announced that they have been hacked and that the hackers have installed spyware on a number of people's smartphones. This vulnerability was discovered by the WhatsApp team and only sent out a notification after the problem was fixed.
You will get a missed WhatsApp call, and in some instanced the call log will be deleted as the spyware can easily trawl through calls, texts and other data. It is also able to activate your phone’s camera and microphone as well as perform other malicious activities. This means you will have no record that the spyware has been installed in your phone.
So to be sure, here is how you can find out whether your device has been hacked:
Check if your battery life hasn't suddenly dropped
See if your data usage has suddenly spiked
Be careful what you click on
Install Lookout Security App
Most importantly, update your version of WhatsApp immediately! This will remove the spyware and keep your smartphone safe.