Top 50 Android applications are sharing users' personal data to advertisers without their knowledge.
According to research by British outlet Channel 4 News, when users grant permissions to applications, they unwittingly granted the same rights to advertisers.
That meant application permissions to access phone contacts would be extended to advertisers.
The model, discovered by MWR Security, breached privacy laws according to the European Commission.
“If users knew about this, I think they would be concerned about it. But at the moment I don't think they are aware of the situation and how widely their information can be used," researcher Nils said, adding that "a lot" of apps in the top 50 were affected.
MWR Security revealed that a one-off app it built sent text messages from the user's phone, their call log and contacts' details to an advertising company called MobClix, which has not responded to comment requests.
Nils told SC Magazine the advertising space was sold by the application developer via MobClix; the permissions allow the third party to access data or add names to the user's contact list or events to their calendar.
“With the Android permission model, the user can decide what the app can access and what it cannot, but most people will not make decisions based on that. They give permission to the third party and hand their trust to the app developer.”
Viviane Reding, vice-president of the European Commission who recently announced sweeping changes to the European Data Protection Directive, told Channel 4 News the model broke laws "because nobody has the right to get your personal data without you agreeing to this".
“Maybe you want somebody to get this data and agree and it's fine. You're an adult and you can do whatever you want. But normally you have no idea what others are doing with your data,” she said.
“They are spotting you, they are following you, they are getting information about your friends, about your whereabouts, about your preferences. That is certainly not what you thought you bought into when you downloaded a free-of-charge app. That's exactly what we have to change.”