QR Scanner -> URL With No Validation

← Improper Platform Usage

qr_url_no_validation   EASY

Description

A scanned QR code’s payload is treated as a trusted URL/deeplink and opened/navigated without validation (Firefox iOS QR-scanner CVE-2025-54145 class).

How it works

A scanned QR code’s payload is treated as a trusted URL or deeplink and opened or navigated without validation. A QR code is fully attacker-controlled, so it can carry a “javascript:” URI, a privileged in-app deeplink, or a phishing link, and the app acts on it as if the user typed it (Firefox iOS QR-scanner CVE-2025-54145 class). This is an offline, deterministic simulation: the handler classifies the payload and reports what it would open or execute. The secure path refuses “javascript:” and privileged “dvma://” deeplinks from an untrusted QR, only allowing plain https external links.

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: frida · Android: adb · iOS: xcrun simctl openurl.
2. Locate the target. From the home index, open QR Scanner -> URL With No Validation (qr_url_no_validation). 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.

Tools (optional)

• frida

Android

• adb

iOS

• xcrun simctl openurl

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:

• crafted QR

Real-world references

Concrete public disclosures that match this vulnerability class:

• CVE-2025-54145 (Firefox iOS QR scanner)
• CVE-2025-54144 (Firefox iOS URL scheme)