Repackaged applications, which are a category of fake applications, play a crucial role in the proliferation of mobile malware. Like fake apps, repackaged apps use social engineering tactics, displaying similar user interface (UI), icon, package names and app labels as the legitimate/official version of the apps they spoofed. This is done to trick users into downloading fake apps and consequently, generating profit.
Based on the research, nearly 80% of the top 50 free apps found in Google Play have bogus versions. These apps can range from business, media and video, and games. In addition, more than half of fake apps today are tagged as ‘high-risk’ and ‘malicious’ due to the risk it pose to the users.
Figure 1. Breakdown of free apps available in Google Play with and without fake versions
Several third-party app stores distribute repackaged apps, some of which are even Trojanized apps or apps that have been modified to add malicious code. Some samples include FAKEBANK, premium abusers, and Trojanized game apps. Cybercriminals add mobile ad software development kits (SDKs) in their bogus apps so as to generate income by pushing advertisements. Furthermore, they also change the mobile ad SDKs of legitimate apps just so they can get the earnings instead of the original developers. Another means of ‘trojanizing’ an app is by inserting malicious code into classes.dex file, which can introduce risks like malware infection and data theft.
Because of the security risks that repackaged apps pose to users, it is advisable for these app stores to include rules and audit mechanism to control the propagation of fake/repacked apps. Google Play has implemented a rule preventing apps which are similar in terms of code and physical appearance with an already existing app.
In the past, we discussed how repackaged apps leverage the popularity of mobile apps with Flappy Bird as a case sample in our monthly mobile review. In our research paper, Fake Apps: Feigning Legitimacy, we provided an in-depth discussion on repackaged apps, its risks to users, and ways which they can secure their mobile devices.
With additional analysis by Symphony Luo
Update as of July 17, 2014, 9:08 A.M. PDT:
Note that the fake apps samples we gathered are from third party sources and none was found in Google Play.
