There are many signs indicating that the WhatsApp application on your phone has been hacked, and these signs include the following: Discovering a rapid depletion of battery life could be a potential sign of compromise. If you're using mobile data and notice a rapid depletion of your data plan, it could indicate that your WhatsApp application might be compromised. If you discover unfamiliar apps on your phone that you didn't download and don't recognize the source of, it could be an indication of a compromised device. Changes in certain phone settings that you didn't make could be a sign of compromise. Active devices on your WhatsApp that you do not own could be an indication of compromise.