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18,000 Android Apps Found Violating Ad Tracking Rules

The International Computer Science Institute in Berkeley, California, has discovered that many popular apps can still track your internet activities, even when you try to use an Android privacy control to stop it.

 & Michael Kan Principal Reporter

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Getting online advertisers to stop tracking you over Android may not be as easy it seems. New research has found that over 18,000 Android apps can create permanent records on their users, even when they try to stop the tracking.

The apps in question should only be collecting a digital "advertising ID" from your phone as a way to serve up targeted ads. If you'd like to opt out, all you should need to do is go to the phone's settings and reset the advertising ID.

However, the International Computer Science Institute in Berkeley, California, has discovered that many popular apps are doing more than just capturing the advertising ID from Android phones. They're also collecting other identifiers, such as the device's serial number, the IMEI number, and other hardware or network indicators — none of which you can reset.

As a result, the apps can still identify your device, even if you decide to reset the advertising ID, said Serge Egelman, a researcher at the institute. "What little users can do is use the privacy controls, but as this research shows, those controls don't appear to do anything," he told PCMag.

The data collection also appears to violate Google's own developer policies, which forbids apps from collecting the advertising ID with device information. According to Egelman's findings, which were first reported by CNET, some of the most popular Android apps, with millions of installs, all engage in the practice. Much of the data is also being sent to various ad networks.

Research from AppCensus

However, Google is pushing back on some of the research. The company told PCMag that collecting both the advertising ID and other device indicators can be done for legitimate purposes, like detecting fraud or account registrations, which is permitted under Google's policy.

Nevertheless, the tech giant said it's taking action against many of the apps identified in Egelman's research. "We take these issues very seriously. Combining Ad ID with device identifiers for the purpose of ads personalization is strictly forbidden," the company said in a statement. "We're constantly reviewing apps —including those listed in the researcher's report — and will take action when they do not comply with our policies."

Still, Egelman said the company should be doing more to stop the online tracking. "Google has made a choice to allow this," he said, noting that the iOS versions of the same apps don't have the same capabilities. "iOS has solved this problem by simply making the identifiers unavailable to developers."

The institute has created a service calls AppCensus, which can tell you what data a mobile app is collecting from your phone. Simply type in the app's name, and AppCensus will provide you a privacy analysis.

To reset an Android phone's advertising ID, go to Settings > Google > Ads to access the option.

About Our Expert

Michael Kan

Michael Kan

Principal Reporter

My Experience

I've been a journalist for over 15 years. I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017, where I cover satellite internet services, cybersecurity, PC hardware, and more. I'm currently based in San Francisco, but previously spent over five years in China, covering the country's technology sector.

Since 2020, I've covered the launch and explosive growth of SpaceX's Starlink satellite internet service, writing 600+ stories on availability and feature launches, but also the regulatory battles over the expansion of satellite constellations, fights with rival providers like AST SpaceMobile and Amazon, and the effort to expand into satellite-based mobile service. I've combed through FCC filings for the latest news and driven to remote corners of California to test Starlink's cellular service.

I also cover cyber threats, from ransomware gangs to the emergence of AI-based malware. In 2024 and 2025, the FTC forced Avast to pay consumers $16.5 million for secretly harvesting and selling their personal information to third-party clients, as revealed in my joint investigation with Motherboard.

I also cover the PC graphics card market. Pandemic-era shortages led me to camp out in front of a Best Buy to get an RTX 3000. I'm now following how the AI-driven memory shortage is impacting the entire consumer electronics market. I'm always eager to learn more, so please jump in the comments with feedback and send me tips.

The Best Tech I've Had:

  • My first video game console: a Nintendo Famicom
  • I loved my Sega Saturn despite PlayStation's popularity.
  • The iPod Video I received as a gift in college
  • Xbox 360 FTW
  • The Galaxy Nexus was the first smartphone I was proud to own.
  • The PC desktop I built in 2013, which still works to this day.

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