Detecting Google Play Store Tampering

TL;DR

Yes, some tampering with the Google Play Store can be detected, but it’s not foolproof. Methods include checking app signatures, verifying package integrity, using SafetyNet Attestation (though this is being phased out), and monitoring for unusual permissions or behaviour. The effectiveness depends on the sophistication of the tamperer.

Detecting Google Play Store Tampering: A Step-by-Step Guide

1. Understand the Risks
• Malicious actors might modify apps before distribution (e.g., injecting malware).
• Compromised devices could have altered Play Store clients, leading to fake updates or app installations.
• Rooted devices are more vulnerable as they bypass security checks.
2. Check App Signatures

Every Android app is digitally signed by the developer. Verify that the signature matches the expected one for legitimate apps.

• Using adb: You can extract the signing certificate using:

  adb shell pm dump | grep -i signature

• Compare this signature with the official developer’s published key. Google Play Console provides information about app signing keys.
3. Verify Package Integrity (APK Hash)

Calculate the hash of the APK file and compare it to a known good value.

• Using adb:

  adb shell pm path

  will give you the APK’s location. Then, on your computer:

  sha256sum /path/to/apk

• If the hash doesn’t match, the app has been altered.
4. SafetyNet Attestation (Deprecated but Relevant)

Google’s SafetyNet API used to provide a basic device integrity check. It indicated if the device was rooted or had other security compromises.

• Important: Google is phasing out SafetyNet in favour of Play Integrity API (see step 6). Existing implementations may need updating.
5. Monitor App Permissions

Unexpected or excessive permissions can be a sign of tampering.

• Use Android’s permission manager to review the permissions granted to apps.
• Look for permissions that don’t align with the app’s stated functionality.
6. Play Integrity API (Recommended)

This is Google’s replacement for SafetyNet, offering more robust device integrity checks.

• Requires integration into your Android application. It provides a response indicating the integrity of the device and Play Store environment.
• See Google’s official documentation for implementation details.
7. Root Detection (Limited Reliability)

Detecting root status can indicate a compromised device, but it’s easily bypassed.

• Various libraries and techniques exist for root detection. However, sophisticated users can often circumvent these checks.
8. Network Monitoring (Advanced)

Monitor network traffic for suspicious activity originating from the Play Store client or apps.

• Look for connections to unknown servers or unusual data transfers.
• Requires advanced networking knowledge and tools like Wireshark or packet capture analysis.
9. Regular Updates

Keep your Android device and Play Store app updated with the latest security patches.