https://techcrunch.com/2020/03/10/your-vpn-or-ad-blocker-app-could-be-collecting-your-data/

The underpinnings of how app store analytics platforms operate were exposed this week by BuzzFeed, which uncovered the network of mobile apps used by a popular analytics firm Sensor Tower to amass app data. The company had operated at least 20 apps, including VPNs and ad blockers, whose main purpose was to collect app usage data from end users in order to make estimations about app trends and revenues. Unfortunately, these sorts of data collection apps are not new — nor unique to Sensor Tower’s operation.

Sensor Tower was found to operate apps such as Luna VPN, for example, as well as Free and Unlimited VPN, Mobile Data, and Adblock Focus, among others. After BuzzFeed reached out, Apple removed Adblock Focus and Google removed Mobile Data. Others are still being investigated, the report said.