It is relatively easy to find out contact information from messaging apps such as WhatsApp and Telegram. This is shown by a study by a German university.
WhatsApp and telegram
Billions of users worldwide use messaging apps such as WhatsApp, Telegram and Signal. What these services have in common is that you can easily come into contact with people, because the apps search your phone contacts and you can start a conversation based on those phone numbers.
It is precisely that process whereby the apps read your phone contacts, which is very risky according to Business Insider. This is shown by a new study by the German Würzburg University and the Technical University Darmstadt.
The process by which phone numbers are shared with the servers of the messaging apps is called ‘mobile contact discovery’, and according to the researchers, it is then possible to carry out a so-called ‘crawling attack’ on the apps WhatsApp, Telegram and Signal.
Create a behavioral model
The researchers were able to discover random telephone numbers and then analyzed that data. This allowed them to view the profile of those contacts with the name, profile picture, status message and the information when that person was last online.
It shows that few people adjust their privacy settings and that about half set a profile picture on WhatsApp. According to the researchers, malicious parties can build a behavioural model about their victims in this way if they regularly analyze this information.
In addition, it is striking that 40 percent of the users of the users of Signal – an app that strongly focuses on privacy, also have a WhatsApp account. And about half of those Signal users have a profile picture on WhatsApp.
Messages that you send via WhatsApp, Signal and Telegram are always protected with end-to-en