security: add FLAG_IMMUTABLE to PendingIntents #95

Sec0xEd · 2025-12-18T00:18:12Z

Summary

Add FLAG_IMMUTABLE to PendingIntents in ActionServiceImpl and UIIntentsImpl to prevent potential PendingIntent hijacking attacks.

Two PendingIntents were created with FLAG_UPDATE_CURRENT alone, without specifying mutability:

ActionServiceImpl.makeStartActionPendingIntent()
UIIntentsImpl.getPendingIntentForLowStorageNotifications()
Starting from Android 12, apps must explicitly specify the mutability of PendingIntents. Without FLAG_IMMUTABLE, a malicious app could potentially modify the PendingIntent before it's delivered, leading to:
Intent redirection attacks
Data tampering
Privilege escalation

Added FLAG_IMMUTABLE to both PendingIntents since they:

Add FLAG_IMMUTABLE to PendingIntents in ActionServiceImpl and UIIntentsImpl to prevent potential PendingIntent hijacking attacks. Starting from Android 12, PendingIntents should specify mutability explicitly. These PendingIntents don't require modification by external apps, so FLAG_IMMUTABLE is the appropriate choice. References: - https://developer.android.com/reference/android/app/PendingIntent#FLAG_IMMUTABLE - https://developer.android.com/about/versions/12/behavior-changes-12#pending-intent-mutability