Have a look at their privacy policy here.

When you click “Ok” it returns you back to the previous screen which is giving you a choice of “don’t allow” that they won’t accept! So to install this app you MUST allow them to save your entire address book contacts on their servers. I clicked “Don’t Allow” and then it prompted this… Here’s a screenshot of what you are prompted with on first install… Legal? Well for one thing the Israeli founded company is registered in Cyprus, where a lot of online gambling companies register. When you first install Viber on your iPhone or Android it will prompt you to allow access your address book, if allowed Viber not only saves your phone number and details but they ALSO saves the phone numbers and contact info of all your contacts! This is without the knowledge of those on your contact list. To investigate I installed it today and within a few seconds I discovered a lot of alarming stuff about how they gather everyone’s contact info and I do mean everyone. I even checked Google Play on my Android (it has a very handy list of ALL apps ever installed on your Android) and Viber was no where to be found! So my question, where & how did they get “my” contact info and why am I listed as a “Viber” when I’ve never even heard of the app!? I was like, “what?!” How is that possible and we tried calling my listed Viber contact to see what if anything would ring. Recently (original article 2013), I became aware of Viber only because my wife used it to talk to her sister and on her smartphone it showed me already listed as a Viber user. What about yours? Find out now and see why this is important. 81% of all smartphones are powered by Linux.

Keep tabs on the ever changing privacy policy.

Its up to each user if this is ok or not. Viber continues to scan and also save your contacts’ phone numbers from your address book on their servers. However, unlike other apps, which only scan your contacts. Update: Over the past couple of months Viber has been modifying their privacy policy to help increase user confidence.

Viber online when phone turned off