Missing FLAG_SECURE (screen recording exposure)

← Improper Platform Usage

missing_flag_secure   EASY

Description

Sensitive screen allows screenshots/recording (no FLAG_SECURE).

How it works

This secret-bearing screen never sets FLAG_SECURE, so screenshots and screen recording (adb screenrecord, or screen-mirroring malware) can capture it. Sensitive screens must set FLAG_SECURE. This is a native window flag; the button simulates a recorder capturing the frame.

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 shell screencap, adb shell screenrecord, scrcpy.
2. Locate the target. From the home index, open Missing FLAG_SECURE (screen recording exposure) (missing_flag_secure). 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-0291, MASTG-TEST-0293 for the canonical procedure and remediation.

Tools (optional)

• adb shell screencap
• adb shell screenrecord
• scrcpy