Invisible Adware: Unveiling Ad Fraud Targeting Korean Android Users

Authored by SangRyol Ryu  

We live in a world where advertisements are everywhere, and it’s no surprise that users are becoming tired of them. By contrast, developers are driven by profit and seek to incorporate more advertisements into their apps. However, there exist certain apps that manage to generate profit without subjecting users to the annoyance of ads. Is this really good?  

Recently, McAfee’s Mobile Research Team discovered a concerning practice among some apps distributed through Google Play. These apps load ads while the device’s screen is off, which might initially seem convenient for users. However, it’s a clear violation of Google Play Developer policy on how ads should be displayed. This affects not only the advertisers who pay for invisible Ads, but also the users as it drains battery, consumes data and poses potential risks such as information leaks and disruption of user profiling caused by Clicker behavior. 

The team has identified 43 apps that collectively downloaded 2.5 million times. Among the targeted apps are TV/DMB Player, Music Downloader, News, and Calendar applications. McAfee is a member of the App Defense Alliance focused on protecting users by preventing threats from reaching their devices and improving app quality across the ecosystem. We reported the discovered apps to Google, which took prompt action. Most apps are no longer available on Google Play while others are updated by the developer. McAfee Mobile Security detects this threat as Android/Clicker. For more information, and to get fully protected, visit McAfee Mobile Security. 

Many affected apps

How does it work? 

This ad fraud library uses specific tactics to avoid detection and inspection. It deliberately delays the initiation of its fraudulent activities, creating a latent period from the time of installation. What’s more, all the intricate configurations of this library can be remotely modified and pushed using Firebase Storage or Messaging service. These factors significantly add to the complexity of identifying and analyzing this fraudulent behavior. Notably, the latent period typically spans several weeks, which makes it challenging to detect. 

Getting latent period by using Firebase Messaging Service 

It is important to be cautious about the implications of granting permissions, such as excluding ‘power saving’ and allowing ‘draw over other apps’. These permissions can enable certain activities to occur discreetly in the background, raising concerns about the intentions and behavior of the applications or libraries in question. Allowing these permissions can result in more malicious behavior, such as displaying phishing pages, also to displaying ads in the background. 

Asked permissions to run in the background and keep it hidden 

When the device screen is turned off after the latent period, the fetching and loading of ads starts, resulting in users being unaware of the presence of running advertisements on their devices. This ad library registers device information by accessing the unique domain (ex: mppado.oooocooo.com) linked with the application. Then go to Firebase Storage to get the specific advertisement URL and show the ads. It is important to note that this process consumes power and mobile data resources. 

Observed traffic when the screen off 

If users quickly turn on their screens at this point, they might catch a glimpse of the ad before it is automatically closed. 

Example of an advertising site displayed when the screen is off 

In conclusion, it is essential for users to exercise caution and carefully evaluate the necessity of granting permissions like power saving exclusion, or draw over other apps before allowing them. While these permissions might be required for certain legitimate functionalities for running in the background, it is important to consider the potential risks linked with them, such as enabling hidden behaviors or reducing the relevance of ads and contents displayed to users because the hidden Clicker behavior. By using McAfee Mobile Security products, users can further safeguard their devices and mitigate the risks linked with these kinds of malware, providing a safer and more secure experience. For more information, visit McAfee Mobile Security

Indicators of Compromise (IoC’)

Domains:

best.7080music.com 

m.gooogoole.com 

barocom.mgooogl.com 

newcom.mgooogl.com 

easydmb.mgooogl.com 

freekr.mgooogl.com 

fivedmb.mgooogl.com 

krlive.mgooogl.com 

sixdmb.mgooogl.com 

onairshop.mgooogle.com 

livedmb.mgooogle.com 

krbaro.mgooogle.com 

onairlive.mgooogle.com 

krdmb.mgooogle.com 

onairbest.ocooooo.com 

dmbtv.ocooooo.com 

ringtones.ocooooo.com 

onairmedia.ocooooo.com 

onairnine.ocooooo.com 

liveplay.oocooooo.com 

liveplus.oocooooo.com 

liveonair.oocooooo.com 

eightonair.oocooooo.com 

krmedia.oocooooo.com 

kronair.oocooooo.com 

newkrbada.ooooccoo.com 

trot.ooooccoo.com 

thememusic.ooooccoo.com 

trot.ooooccoo.com 

goodkrsea.ooooccoo.com 

krlive.ooooccoo.com 

news.ooooccoo.com 

bestpado.ooooccoo.com 

krtv.oooocooo.com 

onairbaro.oooocooo.com 

barolive.oooocooo.com 

mppado.oooocooo.com 

dmblive.oooocooo.com 

baromedia.oooocooo.com 

musicbada.oouooo.com 

barolive.oouooo.com 

sea.oouooo.com 

blackmusic.oouooo.com 

Android Packages 

About Author

AndyC

Andy Curtis is an award-winning security consultant, researcher and public speaker. He has been working in the computer security industry since the early 1990s, having been employed by state and federal government, leading healthcare and banking providers across three continents. He has given talks about computer security for some of the world’s largest companies, worked with law enforcement agencies on investigations into hacking groups, and is a regular voice on TV and radio explaining IT security threats.

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