Privileged Input-Provider (IME) Event Injection

← Privileged System-Provider Activation

privileged_input_provider_injection   HARD

Description

The default input-method (IME) surface accepts key/motion events from an untrusted caller because a permission/caller check is missing, so a co-resident app injects synthetic input into other apps - typing, taps, confirmations - for local privilege escalation. This is the INJECT direction of the keyboard boundary (attacker drives the privileged IME), not the read/exposure direction (Android IME event-injection CVE-2025-26450 class).

How it works

The default input-method (IME) service is a privileged surface that can synthesize key and motion events into whatever app has focus. Here it accepts a batch of injected events from an untrusted co-resident caller without checking that the caller is the system or holds INJECT_EVENTS, so the attacker drives synthetic taps and keystrokes into other apps and auto-confirms a sensitive action (tapping “approve payment”). This is the inject direction of the keyboard boundary (Android IME event-injection CVE-2025-26450 class), the opposite of read/exfil interception. The secure path requires the caller to be the system or hold the injection permission and refuses untrusted callers. The “real state” panel lists the input providers actually enabled on this device (Settings.Secure enabled IMEs and accessibility services); enabling one and granting INJECT_EVENTS or an accessibility service fully arms the injection path.

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, frida.
2. Locate the target. From the home index, open Privileged Input-Provider (IME) Event Injection (privileged_input_provider_injection). 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
• frida

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:

• malicious companion app
• injected key/motion events

Real-world references

Concrete public disclosures that match this vulnerability class:

• CVE-2025-26450 (Android IME key/motion-event injection, missing permission check)