Authored by Wenfeng Yu and ZePeng Chen
As smartphones have turn into an integral a part of our day by day lives, malicious apps have grown more and more misleading and complicated. Lately, we uncovered a seemingly innocent app known as “BMI CalculationVsn” on the Amazon App Retailer, which is secretly stealing the package deal identify of put in apps and incoming SMS messages underneath the guise of a easy well being software. McAfee reported the found app to Amazon, which took immediate motion, and the app is not out there on Amazon Appstore.
Determine 1. Utility printed on Amazon Appstore
Superficial Performance: Easy BMI Calculation
On the floor, this app seems to be a primary software, offering a single web page the place customers can enter their weight and peak to calculate their BMI. Its interface appears totally per a normal well being software. Nevertheless, behind this harmless look lies a spread of malicious actions.
Determine 2. Utility MainActivity
Malicious Actions: Stealing Non-public Knowledge
Upon additional investigation, we found that this app engages within the following dangerous behaviors:
- Display screen Recording: The app begins a background service to file the display and when the consumer clicks the “Calculate” button, the Android system will pop up request display recording permission message and begin display recording. This performance is prone to seize gesture passwords or delicate information from different apps. Within the evaluation of the most recent present samples, it was discovered that the developer was not prepared for this operate. The code didn’t add the recorded mp4 file to the C2 server, and originally of the startRecording() technique, the developer added a code that immediately returns and doesn’t execute comply with code.
Determine 3. Display screen Recorder Service Code
When the recording begins, the permission request dialog shall be displayed.
Determine 4. Begin Recording Request.
- Put in App Data: The app scans the system to retrieve a listing of all put in functions. This information might be used to determine goal customers or plan extra superior assaults.
Determine 5. Add Consumer Knowledge
- SMS Messages: It intercepts and collects all SMS messages acquired on the system, doubtlessly to seize one-time password (OTP), verification codes and delicate info. The intercepted textual content messages shall be added to Firebase (storage bucket: testmlwr-d4dd7.appspot.com).
Malware underneath improvement:
In line with our evaluation of historic samples, this malicious app continues to be underneath improvement and testing stage and has not reached a accomplished state. By looking for associated samples on VirusTotal primarily based on the malware’s package deal identify (com.zeeee.recordingappz) revealed its improvement historical past. We will see that this malware was first developed in October 2024 and initially developed as a display recording app, however halfway by the app’s icon was modified to the BMI calculator, and the payload to steal SMS messages was added within the newest model.
Determine 6. The Timeline of Utility Growth
The tackle of the Firebase Set up API utilized by this app makes use of the character “testmlwr” which signifies that this app continues to be within the testing part.
App Developer Data:
In line with the detailed details about this app product on the Amazon web page, the developer’s identify is: “PT. Visionet Knowledge Internasional”. The malware creator tricked customers by abusing the names of an enterprise IT administration service supplier in Indonesia to distribute this malware on Amazon Appstore. This reality means that the malware creator could also be somebody with information of Indonesia.
Determine 7. Developer Data
The way to Shield Your self
To keep away from falling sufferer to such malicious apps, we advocate the next precautions:
- Set up Trusted Antivirus Apps: Use dependable antivirus software program to detect and stop malicious apps earlier than they’ll trigger hurt.
- Evaluation Permission Requests: When putting in an app, rigorously study the permissions it requests. Deny any permissions that appear unrelated to its marketed performance. As an illustration, a BMI calculator has no legit motive to request entry to SMS or display recording.
- Keep Alert: Look ahead to uncommon app habits, akin to diminished system efficiency, fast battery drain, or a spike in information utilization, which might point out malicious exercise working within the background.
Conclusion
As cybercrime continues to evolve, it’s essential to stay vigilant in defending our digital lives. Apps like “BMI CalculationVsn” function a stark reminder that even the only instruments can harbor hidden threats. By staying alert and adopting strong safety measures, we are able to safeguard our privateness and information.
IoC
Distribution web site:
- hxxps://www.amazon.com/PT-Visionet-Knowledge-Internasional-CalculationVsn/dp/B0DK1B7ZM5/
C2 servers/Storage buckets:
- hxxps://firebaseinstallations.googleapis.com/v1/tasks/testmlwr-d4dd7
- hxxps://6708c6e38e86a8d9e42ffe93.mockapi.io/
- testmlwr-d4dd7.appspot.com
Pattern Hash:
- 8477891c4631358c9f3ab57b0e795e1dcf468d94a9c6b6621f8e94a5f91a3b6a
