Every exported activity, URL scheme and universal link is an entry point another app or a web page can call with values it chooses. An unverified link or an exported screen that performs a transfer hands that authority to anyone.
- Export only the components other apps must reach, and protect them with permissions.
- Prefer verified links (Android App Links with
autoVerify, iOS universal links) to custom URL schemes. - Use explicit, immutable
PendingIntents, and share single files with temporary URI grants rather than paths. - Validate every parameter that arrives through IPC as untrusted input.
MASTG tests in the local projects
The local projects run these OWASP MASTG v2.0.0 tests for MASVS-PLATFORM-1, as tests you can repeat on your own machine.
| MASTG test | Platform | Project |
|---|---|---|
| MASTG-TEST-0370: Missing Input Validation in Custom URL Scheme Handlers | iOS | Keep an iOS app's storage, links and web bridge in bounds · LinkTests |
| MASTG-TEST-0395: Missing Input Validation in Universal Link Handlers | iOS | Keep an iOS app's storage, links and web bridge in bounds · LinkTests |
| MASTG-TEST-0364: Exported And Unprotected Activities That Expose Sensitive Functionality | Android | Repair an Android app's links, components, network policy and storage · ComponentTests |
| MASTG-TEST-0393: Use of Unverified App Links | Android | Repair an Android app's links, components, network policy and storage · ComponentTests |
| MASTG-TEST-0394: Missing Input Validation in Custom URL Scheme Handlers | Android | Repair an Android app's links, components, network policy and storage · LinkTests |
Guides on this site
Harden an iOS app's storage, network and entry points
Store secrets in the Keychain with the narrowest accessibility class, set file protection explicitly, keep App Transport Security on, prefer universal links, constrain WKWebView bridges, keep step-up keys in the Secure Enclave, verify App Attest on the server and ship an accurate privacy manifest, mapped to OWASP MASVS 2.1.
Harden an Android app's storage, network and entry points
Encrypt local secrets with Android Keystore keys now that Jetpack Security is deprecated, set transport policy in Network Security Configuration, close exported components and mutable PendingIntents, confine WebViews, verify App Links and judge Play Integrity verdicts on the server, mapped to OWASP MASVS 2.1.
Review mobile storage, links and platform permissions
Keep local artifacts and platform entry points from exposing authority that belongs on the server.
Review trust boundaries in mobile and native clients
Protect local data and platform interactions while keeping server-side authorization independent of the client’s behavior.
Worked threat model: a mobile banking app
A complete worked threat model for a mobile banking-style app: the data-flow diagram and its elements, STRIDE threats on the client, the transport and the backend, and the mitigations mapped to OWASP MASVS v2 controls and current Android and iOS platform APIs.
Practice
- Keep an iOS app's storage, links and web bridge in bounds · Local project
- Repair an Android app's links, components, network policy and storage · Local project
References
List data from the publisher. A guide is listed as the main subject when the weakness or risk is what the guide is about, and as covering it when a dedicated section or worked example addresses it.
Control statements are quoted from OWASP MASVS v2.1.0, licensed CC BY-SA 4.0; the rest is this site's summary. MASTG tests are those the iOS and Android projects here run, with their titles from mas.owasp.org. License.