The research analysed over 300 Google Play apps, including Uber, Twitter, Tinder and Snapchat, for the signatures of 25 trackers, unknown to users at the time of app installation and primarily used for targeted advertising, behavioural analytics and location tracking.

The study found that over 75% of the apps analysed contain the signatures of trackers, but trackers can also be added to new versions of apps in the future as software is developed. 

Researchers at Yale Privacy Lab said the findings raise serious concerns around privacy. “Lack of transparency about the collection, transmission, and processing of data via these trackers raises serious privacy concerns and may have grave security implications for mobile software downloaded and in active use by billions of people worldwide."

According to the researchers, trackers and Android apps are partial ‘black boxes', making analysis and auditing difficult.

Yale Privacy Lab is using the study to call for increased transparency from app developers and Google. The researchers said: “Android users, and users of all app stores, deserve a trusted chain of software development, distribution, and installation that does not include unknown or masked third-party code.” 

Exodus Privacy’s web-based interface has been made available to the public at https://exodus-privacy.eu.org.