Your free Android apps talk to thousands of ad sites

If you've used ad-sponsored Android apps, you've probably wondered where those ads are coming from, and whether or not there's anything to be worried about. According to French researchers, you have a reason to be cautious. They've found a way to automatically scan Android apps for connections to advertising and user tracking sites, and some of those programs are more than a little dodgy. A selection of 2,000 free Google Play apps connected to a whopping 250,000 sites spread over 2,000 domains. Most of them talk to only a handful of sites (Google's ad services dominate the top 10), but 10 percent connect to 500 or more -- one egregious offender links to over 2,000 sites. Only 30 percent of the apps talked to user tracking sites, but some of those were communicating with 800 or more addresses.

The actual danger to your phone isn't likely to be high. Only a small slice of those apps appeared to connect to suspicious sites, and many of the rest come from developers that Google holds in high esteem. Also, the researchers were using a phone running Android 4.1 Jelly Bean, so their experience might be different than what you'd get running the latest version of Lollipop. Still, the issue is that you rarely know which ad and tracker sites are involved, and there's no easy way to block the connections you don't want. While this study doesn't mean that you should ditch ad-backed apps entirely, it does serve as a friendly reminder that you should be careful before grabbing them.

[Image credit: Family O'Abe, Flickr]