Symantec recently spotted a new tactic being used by apps on the Google Play Store to stealthily perform ad-clicking on users’ devices. A developer known as Idea Master has published two popular apps on the Play Store in the past year, with a collective download count of approximately 1.5 million. Symantec has informed Google of the observed behaviour and the apps have now been removed from the Play Store.
The two apps, a notepad app (Idea Note: OCR Text Scanner, GTD, Color Notes) and a fitness app (Beauty Fitness: daily workout, best HIIT coach), are packed using legitimate packers originally developed to protect the intellectual property of Android applications. Android packers can change the entire structure and flow of an Android Package Kit (APK) file, which complicates things for security researchers who want to decipher the APK’s behavior. This also explains the developer’s ability to remain on Google’s Play Store performing malicious acts under the radar for nearly a year before being detected.
Unlike hidden views where the view is set to transparent in order to hide content from the user, this threat actor deploys a much more cunning way of running the advertisements while keeping them hidden from the user. The app can then initiate an automated ad-clicking process that produces ad revenue. As threat actors generate ghost clicks and ad revenue, impacted devices will suffer from drained batteries, slowed performance, and a potential increase in mobile data usage due to frequent visits to advertisement websites.
These apps went unnoticed on the Google Play Store for nearly a year, affecting roughly 1.5 million users before Symantec uncovered their sneaky behaviour. The apps’ use of Android packers and the unusual method of hiding advertisements adds a level of complexity for security researchers.
Symantec and Norton products detect these apps as the following:
Since the applications are still available on Google Play, we strongly encourage users to manually uninstall them from their devices.
Additionally, Symantec advises users to take the following precautions:
• Keep your software up to date.
• Do not download apps from unfamiliar sites.
• Only install apps from trusted sources.
• Pay close attention to the permissions requested by apps.
• Install a suitable mobile security app, such as Norton or Symantec Endpoint Protection Mobile, to protect your device and data.
• Make frequent backups of important data.
You can read the full blog here.