Internet security company Bitdefender has said that adware is now found on 90 percent of free Android apps, with 75 percent classed as ‘aggressive’.
 
Such adware can create shortcuts on smartphone homescreens, change default search engine settings, and push notifications to the Android notification tray, all of which can reduce device performance.
 
Bitdefender chief security researcher Catalin Cosoi said the Android permission system is unable to provide information about adware or the resources it can access, meaning it’s difficult for users to spot aggressive adware behaviour until the app has been installed or antivirus software has flagged it.
 
The most popular app to include the aggressive adware us Ant Smasher, which has been downloaded from Google Play more than 50 million times and is also available on third party app stores. Galaxy S3 Go Launcher Ex – which changes device homescreens to resemble a Samsung Galaxy S3 – is also a widespread app known to contain aggressive adware.