Each WhatsApp account history is occasionally stored and synchronized with a backup copy located on the application server. This measure enables simultaneous use of one account on several devices or its complete transfer when changing a phone number.
WhaSpy exploits the widespread vulnerability of cellular networks based on SS7 by using the security hole of mobile operators and remote intercepting a packet of incoming data by phone number (including the QR code needed to verify WhatsApp). After that, the history of compromised account is uploaded to the virtual Android device. Then archive with account history is formed and becomes available for download on the Dashboard.