Screenshot / Task-Switcher Leakage

← Insecure Data Storage

screenshot_taskswitcher_leakage   EASY

Description

Sensitive screen rendered into the app-switcher snapshot with no FLAG_SECURE.

How it works

This sensitive screen does not set FLAG_SECURE (Android) and does not blur its iOS snapshot, so it is eligible to be captured into the recents (task-switcher) thumbnail when the app is backgrounded, readable by anyone with the device or via a recents screenshot. A researcher can confirm the posture with the FLAG_SECURE probe and by opening the app switcher; setting FLAG_SECURE / setRecentsScreenshotEnabled(false) would hide the thumbnail. The offline model still tracks the background/foreground state when the native probe is unavailable.

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 Insecure Data Storage category (e.g. --dart-define-from-file=config/flavors/dev.json) and run on an emulator/simulator you control. The demo needs no external tooling; for the optional on-device reproduction the relevant tools are: Android: adb shell screencap, adb shell screenrecord, scrcpy · iOS: idevicescreenshot, QuickTime screen recording.
2. Locate the target. From the home index, open Screenshot / Task-Switcher Leakage (screenshot_taskswitcher_leakage). 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. Exercise the flow that persists data, then inspect on-device storage (adb shell run-as <pkg> / pull the app sandbox, or objection’s android keystore/ios nsuserdefaults helpers) and confirm the sensitive value is present in cleartext or without hardware backing.
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-0289, MASTG-TEST-0291, MASTG-TEST-0292, MASTG-TEST-0290 for the canonical procedure and remediation.

Tools (optional)

Android

• adb shell screencap
• adb shell screenrecord
• scrcpy

iOS

• idevicescreenshot
• QuickTime screen recording