SSRF via URL / Media Handler

← Improper Platform Usage

ssrf_url_media_handler   MEDIUM

Description

An attacker-controlled URL parameter passed into a fetch/media loader is not restricted to an allowlist, so the app can be steered to internal/loopback endpoints (WhatsApp iOS CVE-2026-23866 SSRF-via-URL-scheme class).

How it works

An attacker-controlled URL parameter is passed into a fetch or media loader with no allowlist and no check that the destination is a public host. The app can be steered at internal, loopback, or link-local endpoints, here the cloud metadata service (169.254.169.254), issuing requests from inside the trust boundary (WhatsApp iOS CVE-2026-23866 SSRF-via-URL-scheme class). The vulnerable path opens a real socket to the caller URL, so the loopback or metadata request actually leaves the device and can be watched in a proxy. The secure path only fetches https URLs on a public-host allowlist, refusing all internal targets without dispatching.

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: Burp Suite, mitmproxy.
2. Locate the target. From the home index, open SSRF via URL / Media Handler (ssrf_url_media_handler). 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)

• Burp Suite
• mitmproxy

Real-world references

Concrete public disclosures that match this vulnerability class:

• CVE-2026-23866 (WhatsApp iOS SSRF)