Authored by SangRyol Ryu
Cybercriminals are always after illegal advertising revenue. As we have previously reported, we have seen many mobile malwares masquerading as a useful tool or utility, and automatically crawling ads in the background. Recently the McAfee Mobile Research Team has identified new Clicker malware that sneaked into Google Play. In total 16 applications that were previously on Google Play have been confirmed to have the malicious payload with an assumed 20 million installations.
McAfee security researchers notified Google and all of the identified apps are no longer available on Google Play. Users are also protected by Google Play Protect, which blocks these apps on Android. McAfee Mobile Security products detect this threat as Android/Clicker and protect you from malware. For more information, to get fully protected, visit McAfee Mobile Security.
How it works
The malicious code was found on useful utility applications like Flashlight (Torch), QR readers, Camara, Unit converters, and Task managers:
Once the application is opened, it downloads its remote configuration by executing an HTTP request. After the configuration is downloaded, it registers the FCM (Firebase Cloud Messaging) listener to receive push messages. At first glance, it seems like well-made android software. However, it is hiding ad fraud features behind, armed with remote configuration and FCM techniques.
Attribute name
Known meaning of the value
FCMDelay
Initial start hours after first installation
adButton
Visivility of a button of Advertisement
adMob
AdMob unit ID
adMobBanner
AdMob unit ID
casOn
Whether CAS library works or not
facebookAd
FaceBook Ad ID
fbAdRatio
Ratio of FB AD
googleAdRatio
Ratio of AdMob
is
Decide BootService to run or not
urlOpen
to open popup or not when starts PowerService
popUrl
URL for PowerService
popUpDelay
Delay time for PowerService
liveUrl
URL for livecheck service
pbeKey
Key for making unique string
playButtonList
URL for other service
reviewPopupDialog
‘y’ it shows review dialog
tickDelay
Delay time for TickService
tickEnable
Value of TickService enabled
tickRandomMax
Value of TickService random delay
tickRandomMin
Value of TickService random delay
tickType
Set the type of TickService
updateNotiVersion
Value for showing update activity
The FCM message has various types of information and that includes which function to call and its parameters. The picture below shows some of FCM message history:
When an FCM message receives and meets some condition, the latent function starts working. Mainly, it is visiting websites which are delivered by FCM message and browsing them successively in the background while mimicking user’s behavior. This may cause heavy network traffic and consume power without user awareness during the time it generates profit for the threat actor behind this malware. In the picture below there is an example of the network traffic generated to get the information required to generate fake clicks and the websites visited without user’s consent or interaction:
Malicious components: CAS and LivePosting
So far, we have identified two pieces of code related to this threat. One is “com.click.cas” library which focuses on the automated clicking functionality while “com.liveposting” library works as an agent and runs hidden adware services:
Depending on the version of the applications, some have both libraries working together while other applications only have “com.liveposting” library. The malware is using installation time, random delay and user presence to avoid the users from noticing these malicious acts. The malicious behavior won’t start if the installation time is within an hour and during the time the user is using the device, probably to stay under the radar and avoid being detected right away:
Conclusion
Clicker malware targets illicit advertising revenue and can disrupt the mobile advertising ecosystem. Malicious behavior is cleverly hidden from detection. Malicious actions such as retrieving crawl URL information via FCM messages start in the background after a certain period of time and are not visible to the user.
McAfee Mobile Security detects and removes malicious applications like this one that may run in the background without user’s knowledge. Also, we recommend having a security software installed and activated so you will be notified of any mobile threats present on your device in a timely manner. Once you remove this and other malicious applications, you can expect an extended battery time and you will notice reduced mobile data usage while ensuring that your sensitive and personal data is protected from this and other types of threats.
IoCs (Indicators of Compromise)
liveposting[.]net
sideup[.]co[.]kr
msideup[.]co[.]kr
post-blog[.]com
pangclick[.]com
modooalba[.]net
SHA256
Package name
Name
Downloaded
a84d51b9d7ae675c38e260b293498db071b1dfb08400b4f65ae51bcda94b253e
com.hantor.CozyCamera
High-Speed Camera
10,000,000+
00c0164d787db2ad6ff4eeebbc0752fcd773e7bf016ea74886da3eeceaefcf76
com.james.SmartTaskManager
Smart Task Manager
5,000,000+
b675404c7e835febe7c6c703b238fb23d67e9bd0df1af0d6d2ff5ddf35923fb3
kr.caramel.flash_plus
Flashlight+
1,000,000+
65794d45aa5c486029593a2d12580746582b47f0725f2f002f0f9c4fd1faf92c
com.smh.memocalendar
달력메모장
1,000,000+
82723816760f762b18179f3c500c70f210bbad712b0a6dfbfba8d0d77753db8d
com.joysoft.wordBook
K-Dictionary
1,000,000+
b252f742b8b7ba2fa7a7aa78206271747bcf046817a553e82bd999dc580beabb
com.kmshack.BusanBus
BusanBus
1,000,000+
a2447364d1338b73a6272ba8028e2524a8f54897ad5495521e4fab9c0fd4df6d
com.candlencom.candleprotest
Flashlight+
500,000+
a3f484c7aad0c49e50f52d24d3456298e01cd51595c693e0545a7c6c42e460a6
com.movinapp.quicknote
Quick Note
500,000+
a8a744c6aa9443bd5e00f81a504efad3b76841bbb33c40933c2d72423d5da19c
com.smartwho.SmartCurrencyConverter
Currency Converter
500,000+
809752e24aa08f74fce52368c05b082fe2198a291b4c765669b2266105a33c94
com.joysoft.barcode
Joycode
100,000+
262ad45c077902d603d88d3f6a44fced9905df501e529adc8f57a1358b454040
com.joysoft.ezdica
EzDica
100,000+
1caf0f6ca01dd36ba44c9e53879238cb46ebb525cb91f7e6c34275c4490b86d7
com.schedulezero.instapp
Instagram Profile Downloader
100,000+
78351c605cfd02e1e5066834755d5a57505ce69ca7d5a1995db5f7d5e47c9da1
com.meek.tingboard
Ez Notes
100,000+
4dd39479dd98124fd126d5abac9d0a751bd942b541b4df40cb70088c3f3d49f8
com.candlencom.flashlite
손전등
1,000+
309db11c2977988a1961f8a8dbfc892cf668d7a4c2b52d45d77862adbb1fd3eb
com.doubleline.calcul
계산기
100+
bf1d8ce2deda2e598ee808ded71c3b804704ab6262ab8e2f2e20e6c89c1b3143
com.dev.imagevault
Flashlight+
100+
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