Click-fraud apps frequently appear on Google Play and third-party markets. They are sometimes hard to identify because the malicious behavior that simulates clicks is similar to the behavior of many legitimate applications (using common API calls and permissions). Further, part of the malicious code does not reside in the original malware and comes from a control server. Using special methods to perform the clicking allows the attackers to decide when and how pursue their fraud.
The McAfee Mobile Malware Research Team recently found on Google Play a group of Android/Clickers published by the developer “TubeMate 2.2.9 SnapTube YouTube Downloader J.” Five apps were updated on Google Play on August 4 and were removed a few days later, along with the developer profile.
By checking “com.ggnegmth.app” on GooglePlay we saw something suspicious in this application: a nonsense name, no description, and poorly reviewed. Of course, those traits do not guarantee an app is malicious, but this lineup should serve as a warning for Android users looking for new apps.
Analyzing and reverse engineering this sample shows us a DeviceAdminReceiver class that connects to a hardcoded URL to obtain parameters that indicate how and where to perform click-fraud activities:
This function is part of a service initiated by a receiver related to DeviceAdmin.
Once the URL is requested, the control server returns an HTML page with the parameters in an uncommon way—inside the title tag, as we see in the following:
All the parameters are in one line, but the malware interprets them using the string “eindoejy” to separate them, obtaining the target URL, JavaScript functions to perform clicks, HTTP headers used in the fraudulent HTTP request, and another Google Play package to monetize the clicks in the abused ad network. We thought that string “eindoejy” could be an anagram of “I enjoyed” or “die enjoy,” but we found other variants in which the word used to split the parameters is different.
Once installed, Android/Clicker.BN adds an icon to the main menu that is not related to the downloaded app from Google Play. The new icon appears to be a system utility. Some examples of the icons loaded by the malware:
When Android/Clicker.BN executes, it requests device administration privileges:
Some of the apps can access YouTube inside a WebView and list trending channels, others lock and blacken the screen, and others crash the UI while in the background running click fraud—which not only harms advertisers and publishers, but also generates malicious traffic on infected devices, impacts battery and overall usage performance, and opens the door to new malicious payloads.
McAfee Mobile Security detects this threat as Android/Clicker.BN!Gen and prevents its execution. To further protect yourself against malicious apps, use only legitimate app stores, and pay attention to suspicious traits such as nonsense names, missing descriptions, and poor reviews. Also verify that the app’s request for permissions are related to its functionality. Be wary when apps request device administration API access, which is usually requested only by security apps, antimalware, mobile device management, or corporate email clients. Most apps and games will never ask for device admin rights.
SHA-256 hashes:
- b212cb284f6aba06599877ab49c1e0373909d65bd6f3c03f01d8c0e3d88dc85a
- f309ab9ecd2fb4895ba8eca873976e124817b1d8acfc553aa91798b6e82d79ea
- d642e69a53cba9b7c2a612173f9b410a6b1ac055ed575ad8019b263a5edaaeaf
- 50247e85ecb6452aa847a572ca04ab310cf8e9288520f824d13ebcc207be7c13
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