+MASTG-BEST-0034 Validate WebView Input (iOS)

MASTG-BEST-0034 Validate WebView Input (iOS)

Platform: iOS
Knowledge: MASTG-KNOW-0076

Always treat any data passed to a WKWebView as untrusted unless it is fully controlled by the app. This includes URLs loaded through load(_:)), local files loaded through loadFileURL), HTML passed to loadHTMLString), JavaScript passed to evaluateJavaScript), and any data inserted into the rendered page.

If the app loads a URL into a WKWebView, the URL should be parsed and validated against a strict allowlist of expected schemes, hosts, paths, and other relevant components. Do not allow attacker-controlled input, such as deep links, custom URL schemes, pasted text, or server-supplied values, to determine arbitrary WebView destinations.

For deep links and custom URL schemes, only accept known commands and fixed destinations. Do not forward arbitrary URL parameters directly into WKWebView.load(_:).

If untrusted data must be displayed inside web content, avoid HTML and JavaScript injection patterns such as innerHTML or string built evaluateJavaScript calls. Prefer safe text only rendering and context appropriate escaping.

If local content is loaded with loadFileURL, keep allowingReadAccessTo as narrow as possible and never combine broad local file access with untrusted HTML or script injection.

1. Overzicht

Titel	Standaard

1.1 Referenties

1.2 Geïdentificeerde eisen

1.3 Gerelateerde regelingen

2. Geïdentificeerde eisen

Eisen
Bron	Eis

3. Gerelateerde regelingen

Regelingen
Bron	Regelgeving

Gekoppelde issues

Koppelingen
Koppelingstype	Issue
is related to	MASTG-TEST-0332 Attacker-Controlled URI in WebViews (iOS)

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- OWASP Application Security Verification Standard (ASVS) 5.0.0, Mai 2025, aus OWASP/ASVS: © 2008-2025 The OWASP Foundation, lizenziert unter CC BY-SA 4.0. Änderungen: in Abschnitte aufgeteilt und in das GRCA-Format umgewandelt, der Wortlaut unverändert. Diese Bearbeitungen stehen ebenfalls unter CC BY-SA 4.0.
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