AccessibilityService Privilege Abuse

← Improper Platform Usage

accessibility_service_privilege_abuse   HARD

CategoryImproper Platform Usage
OWASP Mobile (2024)M4
MASVSMASVS-PLATFORM-1MASVS-AUTH-1
MASWEMASWE-0040
CWECWE-862CWE-284CWE-441
PlatformAndroid

Description

An AccessibilityService performs a privileged action (launching an activity from the background, hiding/suppressing UI, injecting a gesture/click) with insufficient caller / service-state validation, so the a11y capability is abused for privilege escalation or UI manipulation (Android AccessibilityServiceConnection CVE-2025-26462 / CVE-2023-21109 class).

How it works

An AccessibilityService performs a privileged action (launching an activity from the background, hiding or suppressing UI, injecting a gesture) with insufficient caller or service-state validation, so the accessibility capability is abused for privilege escalation or UI manipulation (Android AccessibilityServiceConnection CVE-2025-26462 / CVE-2023-21109 class). Here the vulnerable service launches a fake consent activity from the background with no genuine foreground accessibility event behind it. This is an offline, deterministic simulation. The secure path requires the service to be user-enabled, the action to be tied to a real foreground accessibility event, and the action to be on an allowlist, refusing background launches and UI hiding.

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 Improper Platform Usage 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, accessibility inspector, jadx, drozer.
  2. Locate the target. From the home index, open AccessibilityService Privilege Abuse (accessibility_service_privilege_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. From a co-resident/attacker context (adb shell am start/drozer, or a crafted deep link / QR), send the untrusted input to the exported component or WebView and confirm the app performs the unsafe action (navigation, JS execution, file/URI access) with no validation.
  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)

Real-world references

Concrete public disclosures that match this vulnerability class: