An investigation from privacy advocacy group Privacy International on the flow of personal information has questioned whether Facebook and its advertisers are violating Europe’s GDPR.

To date there have not been any major challenges using the data privacy regulation. There have of course been numerous violations of user privacy, but as these incidents occurred prior to the implementation of GDPR, the old-version of the rules and punishments were used. This investigation from Privacy International could prove to be a landmark.

The investigation itself questions whether Facebook and the app-developers which use its platform for data collection and user identification is acting responsibly and legally. Using the Facebook Software Development Kit (SDK), data is automatically sent back to the social media giant, irrelevant as to whether consent has been collected, or even if the user has a Facebook book account.

“Facebook routinely tracks users, non-users and logged-out users outside its platform through Facebook Business Tools,” Privacy International states on its website.

“App developers share data with Facebook through the Facebook Software Development Kit (SDK), a set of software development tools that help developers build apps for a specific operating system. Using the free and open source software tool called ‘mitmproxy’, an interactive HTTPS proxy, Privacy International has analysed the data that a number of Android apps transmit to Facebook through the Facebook SDK.”

After testing dozens of different apps, Privacy International claims 61% automatically transfer data to Facebook the moment a user opens the app, while others routinely send Facebook data that is incredibly detailed. Some of these users may be logged out of the platform or might not even have a Facebook account in the first place. Developers tested include travel comparison app Kayak, job search company Indeed and crowd-sourced search service Yelp.

Looking at the Kayak example, not only was information transferred back to Facebook once the app was opened and closed, but also during each stage of the search process. In the example Privacy International gives, the user selected a flight from London Gatwick to Tokyo between December 2 and 5, Narita Airport was then selected, before another search was conducted searching for hotels for two adults in the city. All of this information was sent to Facebook without prompt, despite Kayak claiming, ‘don’t worry, we’ll never share anything without your permission’, when the user signs in.

Alone this information is useful, but not incredibly so. However, when you consider the huge number of apps which will be sending information back to Facebook, an incredibly detailed picture of the user can be built. Using the other apps tested in this investigation, Facebook could also learn or make assumptions about the user’s religion (Muslim Pro), music interests (Shazam), salary and disposable income (Indeed Job Search) and interest in physical activities (MyFitnessPal). All of this information could be used to feed incredibly personalised advertisements to the user.

The big question which remains is whether this could be perceived as a violation of GDPR. Facebook has stated it released an update to the SDK which allowed developers to suspend the automatic data transfers, though this was only for version 4.34 and later. With the Opt-out section (the Google advertising ID) automatically turned off, some might suggest the user is being led as opposed to asked.

Another factor which could work against Facebook is the collection of data on users who do not have Facebook accounts; this is much more suspect. As per GDPR, a company has to have a specific and justified reason to collect personal information. It does appear Facebook is collecting information on users despite having no purpose or valid reason to do so.

With fines for violating GDPR up to 3% of annual turnover, the stakes are very high. This could prove to be one of the first tests of the rules, designed to protect the privacy of the general public, and few will be surprised Facebook is a central character in the story. With the social media giant seemingly antagonising many governments around the world, we suspect there will be a queue forming to have a swing with the sharp GDPR stick.