CVE-2023-44129 Messaging - Gaining access to arbitrary content providers via QClipIntentReceiverActivity

The vulnerability is that the Messaging (“com.android.mms”) app patched by LG forwards attacker-controlled intents back to the attacker in the exported “com.android.mms.ui.QClipIntentReceiverActivity” activity. The attacker can abuse this functionality by launching this activity and then sending a broadcast with the “com.lge.message.action.QCLIP” action. The attacker can send, e.g., their own data/clipdata and set Intent.FLAG_GRANT_* flags. After the attacker received that intent in the “onActivityResult()” method, they would have access to arbitrary content providers that have the android:grantUriPermissions="true" flag set.