What Is Joker Malware? How It Infected Android Apps?

Joker is a malicious Trojan that is primarily designed to infect Android users. The spyware communicates with people via apps. 

Joker Malware. How It Infected Android Apps?

In few Google Play Store apps, Joker malware has been discovered. The malware infiltrates the device of a customer with programs, gathers data, and then registers these users without user knowledge or agreement for premium membership.

Joker Trojan malware has been found in Google Play Store applications for three years. Quick Heal Security Labs has recently discovered eight Google Play Store wildcard malware. The eight applications have been reported to Google, and all have since been taken out of its store by the company. Joker Trojan collects data via SMS, contact lists, and device information from the victim's device. The Trojan interacts discreetly with publicity websites and signs up for premium services without the knowledge of the victim.

These requests request notification access at launch, which is used for the obtaining of notification data, according to the Quick Heal report. The program then receives notification data from SMS and requests access to the Contacts. The app makes and manages phone calls when permission is granted. After that, it continues to work without showing the user any malicious conduct.

Malware authors propagated malware applications on Google Play Store using scanner apps, wallpaper applications, and chat apps, according to the cybersecurity corporation. Such programs can easily become objectives.

In July 2020, the Joker virus infected more than 40 Android apps available from the Google Play Store and forced Google to delete the affected Play Store applications. The Joker malware has struck again, this time targeting eight new Android apps. Users' data is stolen, including SMS, contact lists, device information, OTPs, and more. 

In July, Google removed 11 Joker-infected apps from the Play Store, followed by 34 removals in October. The rogue programs had over 120,000 downloads, according to the cybersecurity film Zcaler.

The Zcaler blog stated, "This malware is meant to collect SMS messages, contact lists, and device information, as well as discreetly sign the victim up for premium wireless application protocol (WAP) services."

“Joker is one of the most well-known malware families that targets Android devices on a regular basis." Despite the fact that this virus is well-known, it continues to make its way into Google's official app store by modifying its code, execution methods, or payload retrieval tactics. In a blog post, Zcaler stated, "This malware is designed to collect SMS messages, contact lists, and device information while also secretly signing the victim up for premium wireless application protocol (WAP) services."

Eight Joker Malware Applications:

  1. Auxiliary Message
  2. Fast Magic SMS
  3. Super Message
  4. Free CamScanner 
  5. Super SMS 
  6. Element Scanner
  7. Go Messages
  8. Travel Wallpaper

The Joker malware, for those who don't know, is a popular type that can steal users' SMS messages, contact lists, and device information. It even has the ability to sign consumers up for premium wireless application protocol (WAP) services without their knowledge. 

The malware has been discovered infecting multiple Android apps, and each time it comes back with new code, execution methods, or payload-retrieving strategies, it infects more. The malicious apps were reportedly frequently downloaded, with over 1,20,000 installations on the Google Play Store. Following are the apps that were affected:

1. Tangram App Lock
2. Direct Messenger
3. Private SMS
4. One Sentence Translator 
5. Style Photo Collage
6. Meticulous Scanner
7. Desire Translate
8. Talent Photo Editor 
9. Care Message
10. Part Message
11. PDF Scanner of all good
12. Mint Leaf Message
13. Unique Keyboard
14. Paper Doc Scanner
15. Blue Scanner
16. Hummingbird PDF Converter 

How Did Joker Gain Access To The Device?

The Joker was (and possibly still is) distributed through Google Play store applications. Fortunately, Google detects harmful programs and removes them from Google Play. Furthermore, with services like Google Play Pass, the danger of a device being infected with a Trojan like Joker is reduced. It's worth noting that malware is frequently disseminated via untrustworthy distribution channels including peer-to-peer networks (e.g., torrent clients, eMule), unofficial websites, third-party downloaders, free file hosting pages, freeware download sites, and so on. These are frequently used by cyber thieves to host malicious files that, when downloaded and accessed, install malware. Malware can also be propagated by emails that contain a malicious Microsoft Word, PDF document, executable file (.exe), JavaScript file, or archive file (ZIP, RAR), but only if recipients open the files will their devices be infected (or open files downloaded via included website links). Malware can be installed through a variety of false updates and installers. Instead of installing updates, they just install malware or take advantage of faults or flaws in obsolete software. 

Safety Tips And How To Delete Such Apps

The Joker malware is thought to have gotten around the Google Play Store in three methods. The first method used direct download, in which the payload was transmitted to the command and control (C&C) server via a direct URL. The second approach used a one-stage download that required a stager payload to download the final payload, while the third method (two-stage download) required two-stager payloads.  

To stay safe from malicious apps, users should pay attention to the permissions that an app requests. It's usually a good idea to check the app's comments and reviews before downloading it.  

You can go to the Play Store, search for the app, and then uninstall it from the app page by clicking on the ‘Uninstall' button. This will uninstall the app from your phone.

You can also long-press on the app from the home screen to erase it by dragging it off your screen or clicking the ‘X button on the home screen.

Because the Joker malware keeps reappearing on the Play Store, you can use some standard precautions to avoid downloading potentially malicious apps. Before you download an app, make sure to read the app ratings and reviews. Avoid the app if there are several complaints in the reviews. Also, if you see reviews that exaggeratedly praise the app despite the poor ratings, those reviews are fraudulent, and you should avoid these apps as well.