The inclusion of ads in mobile applications or apps is fraught with privacy or security risks, so beware, says a new study.
These app developers incorporate "in-app ad libraries," which are provided by Google, Apple or other third-parties, for revenue generation.
These libraries retrieve ads from remote servers and run the ads on a user's smartphone periodically. Every time an ad runs, the app developer receives a payment. Significantly, researchers found more than half of the 100,000 of the apps contained so-called ad libraries.
And 297 of the apps included aggressive ad libraries that were enabled to download and run code from remote servers - which raises significant privacy and security concerns.
"Running code downloaded from the Internet is problematic because the code could be anything," says Xuxian Jiang, assistant professor of computer science at North Carolina State University and study co-author.
"For example, it could potentially launch a 'root exploit' attack to take control of your phone - as demonstrated in a recently discovered piece of Android malware called RootSmart."
In Google Play (formerly known as the Android Market) and other markets, many developers offer free apps, according to a North Carolina statement.
Jiang's team looked at a sample of 100,000 apps available on Google Play between March and May 2011 and examined the 100 representative ad libraries used by those apps.
One significant find was that 297 of the apps (one out of every 337 apps) used ad libraries "that made use of an unsafe mechanism to fetch and run code from the Internet - a behaviour that is not necessary for their mission, yet has troubling privacy and security implications," Jiang says.
Jiang's team found that 48,139 of the apps had ad libraries that track a user's location via GPS, presumably to allow an ad library to better target ads to the user.
These ad libraries pose security risks because they offer a way for third parties - including hackers - to bypass existing Android security efforts.
Specifically, the app itself may be harmless, so it won't trigger any security concerns. But the app's ad library may download harmful or invasive code after installation.
These findings will be presented on April 17 at the Vth ACM Conference on Security and Privacy in Wireless and Mobile Networks in Tucson.