Update: Since April 24, when the article below was first published, Check Point researchers learned that the FalseGuide attack is far more extensive than originally understood. Five additional apps containing the malware were found on Google Play, developed by “Анатолий Хмеленко.” The apps were uploaded to the app store as early as November 2016, meaning they hid successfully for five months, accumulating an astounding number of downloads. The updated estimate now includes nearly 2 million infected users
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Is someone trying to build a botnet on Google Play?
Check Point mobile threat researchers detected a new strain of malware on Google Play, Google’s official app store. The malware, dubbed “FalseGuide,” was hidden in more than 40 guide apps for games, the oldest of which was uploaded to Google Play on February 14, 2017. Several of the apps managed to reach more than 50,000 installs, and the total number of infected devices is estimated to reach up to 600,000 devices. Check Point notified Google about the malware, and it was swiftly removed from the app store. At the beginning of April, two new malicious apps were uploaded to Google Play containing this malware, and Check Point notified Google once again.
Similar to previous malware found on Google Play, such as Viking Horde and DressCode,
FalseGuide creates a silent botnet out of the infected devices for adware purposes. A botnet is a group of devices controlled by hackers without the knowledge of their owners. The bots are used for various reasons based on the distributed computing capabilities of all the devices.
FalseGuide requests an unusual permission on installation – device admin permission. The malware uses the admin permission to avoid being deleted by the user, an action which normally suggests a malicious intention. The malware then registers itself to a Firebase Cloud Messaging topic which has the same name as the app. Once subscribed to the topic, FalseGuide can receive messages containing links to additional modules and download them to the infected device. After a long wait, we were able to receive such a module and determine that the botnet is used to display illegitimate pop-up ads out of context, using a background service that starts running once the device is booted. Depending on the attackers’ objectives, these modules can contain highly malicious code intended to root the device, conduct a DDoS attack, or even penetrate private networks.
FalseGuide masquerades as guiding apps for games for two major reasons. First, guiding apps are very popular, monetizing on the success of the original gaming apps. Second, guiding apps require very little development and feature implementation. For malware developers this is a good way to reach a widespread audience with minimal effort. The malicious apps were submitted under the names of two fake developers – Sergei Vernik and Nikolai Zalupkin, suggesting a Russian connection, while the second is clearly (to a Russian speaker) a made up name.
Mobile botnets are a growing trend since early last year, growing in both sophistication and reach. This type of malware manages to infiltrate Google Play due to the non-malicious nature of the first component, which only downloads the actual harmful code. Users shouldn’t rely on the app stores for their protection, and implement additional security measures on their mobile device, just as they use similar solutions on their PCs.
Fig. 1 An app containing FalseGuide malware on Google Play
Appendix 1 – list of malicious apps found on Google Play
| Package name | App name | Date | Min | Max |
| free.oosapp.infofifamobile | Guide or FIFA Mobile | 21.2.17 | 50000 | 100000 |
| info.artapp.guidelegonexoknights | Guide for LEGO Nexo Knights | 15.2.17 | 10000 | 50000 |
| free.oosapp.inforollingsky | Guide for Rolling sky | 20.2.17 | 5000 | 10000 |
| info.artapp.guidelegocitymycity | Guide for LEGO City My City | 14.2.17 | 10000 | 50000 |
| free.oosapp.infoterraria | Guide for Terraria | 20.2.17 | 10000 | 50000 |
| free.oosapp.infoworldoftanksblitz | Справочник для World of Tanks | 20.2.17 | ||
| info.artapp.guidezombietsunami | Руководство для Zombie Tsunami | 15.2.17 | ||
| info.artapp.guidedriftzone | Руководство для Drift Zone 2 | 22.2.17 | 1 | 5 |
| info.artapp.guidemobilelegendsbangbang | Руководство для Mobile Legends | 22.2.17 | 1 | 5 |
| info.artapp.guideinjusticegodsamongus | Руководство для Injustice Gods | 22.2.17 | 1 | 5 |
| info.artapp.guideninjagoshadowofronin | Руководство для Injustice Gods | 22.2.17 | 1 | 5 |
| info.artapp.guideasphaltairborne | Руководство для Asphalt 8 | 22.2.17 | 1 | 5 |
| free.oosapp.infocriminalcase | Справочник для Criminal Case | 21.2.17 | 1 | 5 |
| free.oosapp.infonbalivemobile | Справочник для NBA LIVE Mobile | 21.2.17 | 1 | 5 |
| free.oosapp.infohayday | Справочник для NBA LIVE Mobile | 21.2.17 | 1 | 5 |
| free.oosapp.infosubwaysurfers | Справочник для Subway Surfers | 21.2.17 | 1 | 5 |
| free.oosapp.infozombietsunami | Справочник для Zombie Tsunami | 21.2.17 | 1 | 5 |
| free.oosapp.infogtasanandreas | Справочник для Zombie Tsunami | 20.2.17 | 1 | 5 |
| info.artapp.guideterraria | Руководство для Terraria | 18.2.17 | 1 | 5 |
| info.artapp.guidehayday | Руководство для Hay Day | 18.2.17 | 5 | 10 |
| info.artapp.guideworldoftanksblitz | Руководство для World of Tanks | 18.2.17 | 1 | 5 |
| mobi.guide.pokemon.go.pro | Guide for Pokemon GO | 1.3.17 | 50000 | 100000 |
| guide.tipsamazingspiderman.infopro | Guide Amazing Spider-Man 2 | 2.3.17 | 1000 | 5000 |
| mobi.proguide.lego.marvel.superhero | ProGuide LEGO Marvel Superhero | 1.3.17 | 1000 | 5000 |
| guide.tipsdreamleaguesoccer.infopro | Guide Dream League Soccer | 2.3.17 | 10000 | 50000 |
| mobi.leguide.lego.city.under.cover.pro | LEGUIDE LEGO City Undercover | 27.2.17 | 10000 | 50000 |
| mobi.guide.fnaf2.pro | Руководство для FNAF 2 | 1.3.17 | 1 | 5 |
| mobi.guide.roblox.pro | Руководство для Roblox | 1.3.17 | 1 | 5 |
| guide.tipsfnaftwo.infopro | Guide For FNAF 2 | 8.3.17 | 1000 | 5000 |
| guide.tipsgreattheautovipcity.infopro | Инструцкция The Auto Vip City | 3.3.17 | 1 | 5 |
| mobi.tips.superr.mario.pro | Руководство для Super Mario | 28.2.17 | ||
| mobi.great.the.auto4.pro | Руководство Great The Auto 4 | 28.2.17 | ||
| mobi.guide.cadillacs.pro | Руководство для Cadillacs | 1.3.17 | ||
| mobi.guide.amazing.spider.man2.pro | Руководство для Spider-Man 2 | 28.2.17 | ||
| guide.tipssupermario.infopro | Инструкция к Super Mario | 2.3.17 | ||
| guide.tipslegofriends.infopro | Интсрукция к LEGO Friends | 3.3.17 | 1 | 5 |
| guide.tipsgreattheautofive.infopro | Инструкция к Great The Auto 5 | 2.3.17 | 1 | 5 |
| guide.tipsgreattheautofour.infopro | Инструкция к Great The Auto 4 | 8.3.17 | 1 | 5 |
| guide.tipscadillacs.infopro | Guide for Cadillacs | 3.3.17 | 5000 | 10000 |
| guide.tipsroblox.infopro | Guide for Roblox | 3.3.17 | 10 | 50 |
| mobi.guide.dream.league.soccer.pro | Руководство для League Soccer | 28.2.17 | 1 | 5 |
| mobi.leguide.lego.city.mycity.pro | LEGUIDE LEGO City My City | 27.2.17 | 5000 | 10000 |
| com.megaguide.rollingsky.tricks | Guide for Rolling Sky | 11.4.17 | 500 | 1000 |
| com.megaguide.legoninjagotournament.tricks | Guide for Ninjago Tournament | 6.4.17 | 50000 | 100000 |
| free.guidegame.hungrysharkfree | Guide for Hungry Shark World | 22.11.16 | 100000 | 500000 |
| free.guidegame.fifafree | Guide For FIFA 17 | 30.11.16 | 10000 | 50000 |
| free.guidegame.slitherfree | Guide for slither.io | 29.11.16 | 50000 | 100000 |
| free.guidegame.mortalkombatxfree | Guide for Mortal Kombat X | 23.11.16 | 50000 | 100000 |
| free.guidegame.shadowfightfree | Guide for Shadow fight 3 and 2 | 23.11.16 | 100000 | 500000 |
| Total | 528535 | 1846160 |
Appendix 2 – list of SHA256 hashes:
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