Ordered-Broadcast Result Injection

← Improper Platform Usage

ordered_broadcast_result_injection   MEDIUM

Description

The app sends an ordered broadcast and then TRUSTS the aggregated getResultData() / result-extras, but a co-resident receiver registered at a higher priority runs first and calls setResultData() / setResultExtras() (or abortBroadcast()) to poison or suppress the result the app consumes for a security decision. The attacker sits in the middle of the app’s own broadcast pipeline. The secure path never trusts ordered-broadcast results for security decisions and protects the broadcast with a signature permission (Android ordered-broadcast class).

How it works

The app sends an ordered broadcast and then trusts the aggregated getResultData() and result-extras for a security decision. Ordered broadcasts are delivered in priority order, so a co-resident receiver registered at a higher priority runs first and calls setResultData() or setResultExtras() to poison the result before the app aggregates it. The attacker sits in the middle of the app’s own broadcast pipeline, so the “authoritative” result is attacker-controlled. The secure path guards the broadcast with a signature permission (so the attacker receiver never runs) and never uses an ordered-broadcast result as the source of a security decision.

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, drozer, jadx.
2. Locate the target. From the home index, open Ordered-Broadcast Result Injection (ordered_broadcast_result_injection). 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-0366 for the canonical procedure and remediation.

Tools (optional)

• adb
• drozer
• jadx

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:

• high-priority malicious receiver

Real-world references

Concrete public disclosures that match this vulnerability class:

• Android: ordered broadcasts, setResultData / abortBroadcast