One of the most concerning revelations arising from the recent WikiLeaks publication is the possibility that government organizations can compromise WhatsApp, Telegram and other end-to-end encrypted chat applications. While this has yet to be proven, many end-users are concerned as WhatsApp and Telegram use end-to-end encryption to guarantee user privacy. This encryption is designed to ensure that only the people communicating can read the messages and nobody else in between.
Nevertheless, this same mechanism has also been the origin of a new severe vulnerability we have discovered in both messaging services’ online platform – WhatsApp Web and Telegram Web. The online version of these platforms mirror all messages sent and received by the user, and are fully synced with the users’ device.