Over-Broad Media Access (no scoped photo picker)

← Improper Platform Usage

photo_picker_over_access   EASY

Description

Requests full media/photo-library permission instead of the modern scoped photo picker, over-collecting user photos.

How it works

To let the user attach one photo, the app requests full media-library permission and receives every photo on the device (including sensitive scans), plus standing access to future photos. The modern scoped photo picker returns only the item the user selected and grants no standing permission, collecting exactly what is needed.

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 emulator/simulator you control. The demo needs no external tooling; for the optional on-device reproduction the relevant tools are: MobSF · Android: aapt, jadx, apktool · iOS: ipsw, plutil.
2. Locate the target. From the home index, open Over-Broad Media Access (no scoped photo picker) (photo_picker_over_access). 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-0254, MASTG-TEST-0255 for the canonical procedure and remediation.

Tools (optional)

• MobSF

Android

• aapt
• jadx
• apktool

iOS

• ipsw
• plutil