Implicit Intent Leaks Sensitive Data

← Improper Platform Usage

implicit_intent_sensitive_data   MEDIUM

Description

Sensitive data is placed on an implicit intent (no explicit component/package), so any co-resident app registering a matching filter receives it (Samsung Smart View CVE-2025-21024 class).

How it works

Sensitive extras (an auth token and the account email) are placed on an implicit intent, one that names only an action and sets no explicit component or package, and broadcast. Android resolves an implicit intent by its action and delivers it to every app that registered a matching intent-filter, so a co-resident malicious app that claimed the same action silently receives the payload (the Samsung Smart View CVE-2025-21024 class). On Android, DVMA emits the implicit broadcast and the companion attacker (which claimed the same action) receives the extras. The secure path sends an explicit intent addressed to the single trusted package, so the eavesdropper gets nothing.

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, drozer, jadx.
2. Locate the target. From the home index, open Implicit Intent Leaks Sensitive Data (implicit_intent_sensitive_data). 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.
6. Map it back. Cross-reference the MASTG v2 test(s) MASTG-TEST-0374, MASTG-TEST-0372 for the canonical procedure and remediation.

Tools (optional)

• adb
• drozer
• jadx