Privileged Provider Activation Abuse

← Privileged System-Provider Activation

privileged_provider_activation_abuse   HARD

Description

An app becomes an enabled system provider (accessibility / notification-listener / VPN / IME / device-admin / call-screening / phone-account / MediaProjection / credential-provider) through an enablement flow that can be coerced (tapjacked/overlaid into the toggle) and is not re-confirmed, then exposes a confused-deputy path so the granted capability is driven on an untrusted caller’s behalf - the activation workflow is the security boundary (Android tapjack-to-enable phone-account CVE-2023-20913 class).

How it works

Becoming an enabled system provider (accessibility, notification listener, VPN, IME, device-admin, call-screening, phone-account, media-projection, credential-provider) is the real security boundary. Here the enablement toggle is tapjacked: the confirming tap is delivered through an attacker overlay and the flow never checks FLAG_WINDOW_IS_OBSCURED nor re-confirms, so the app is silently enabled as a phone-account provider. It then acts as a confused deputy, driving the granted capability for an untrusted caller (Android tapjack-to-enable phone-account CVE-2023-20913 class). The secure path refuses an obscured confirmation and re-checks the caller on invoke. The “real state” panel lists the providers actually enabled on this device via Settings.Secure; to fully arm one, enable it in Settings (for example the DVMA custom keyboard, or an accessibility service).

How to exercise it. DVMA is the harness - open this module from the home index and tap the demo action. The screen ships the malicious input and simulates the attacker (e.g. the companion app, crafted intent, or scanned payload) in-process, and the evidence panel prints the proof. The Tools (optional) and Attack inputs below are only needed to reproduce the exploit end-to-end on a real device.

Exploit steps

1. Set up. Build DVMA with a flavor that enables the Privileged System-Provider Activation category (e.g. --dart-define-from-file=config/flavors/dev.json) and run on an Android emulator you control. The demo needs no external tooling; for the optional on-device reproduction the relevant tools are: adb, drozer, jadx.
2. Locate the target. From the home index, open Privileged Provider Activation Abuse (privileged_provider_activation_abuse). The How it works section above describes this module’s specific weakness; the screen states the intended-secure behavior and exposes the vulnerable action.
3. Exploit. Drive the provider-activation / enablement workflow (accessibility, notification-listener, VPN, IME, phone-account, MediaProjection, credential-provider) and confirm the granted capability is invoked on an untrusted caller’s behalf - the enablement flow is the boundary.
4. Observe the evidence. Trigger the vulnerable action and read the evidence panel - it prints the concrete proof (leaked value, accepted replay, executed payload, or unauthorized result).
5. Contrast with the secure path. Run the module’s secure/hardened action (where provided) and confirm the same attack is rejected - this is what a correct implementation should do.

Tools (optional)

• adb
• drozer
• jadx

Attack inputs

Payloads/artifacts you author for the on-device attack. The demo already ships and simulates these in-process (e.g. the malicious companion app / crafted intent is emulated inside the screen), so you only need to craft them to reproduce the exploit on a real device:

• overlay PoC app

Real-world references

Concrete public disclosures that match this vulnerability class:

• CVE-2023-20913 (Android tapjacking enables malicious phone account)