Background Activity Launch Abuse

← Improper Platform Usage

background_activity_launch_abuse   MEDIUM

Description

An untrusted / local caller drives a background component to startActivity() reaching security-sensitive UI, so with no background-activity-launch restriction the app is coerced into phishing overlays, task hijacking, or consent-dialog manipulation on the user’s behalf (Android background-activity-launch CVE-2025-26462 class).

How it works

An untrusted or local caller drives a background component to startActivity() and reaches a security-sensitive UI, a phishing overlay, a task-hijack surface, or a consent dialog it can manipulate, because there is no background-activity-launch restriction (Android CVE-2025-26462 class). Here a background attacker surfaces a fake consent dialog over the user. This is an offline, deterministic simulation. The secure path enforces background-activity-launch rules: the caller must be in the foreground or present a valid launch token, refusing the background launch otherwise.

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 Background Activity Launch Abuse (background_activity_launch_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.
6. Map it back. Cross-reference the MASTG v2 test(s) MASTG-TEST-0364 for the canonical procedure and remediation.

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:

• malicious companion app

Real-world references

Concrete public disclosures that match this vulnerability class:

• CVE-2025-26462 (Android unauthorized background activity launch -> LPE)