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    Frontend Security Testing

    Comprehensive guide to testing client-side security in AI-generated applications. Learn how to find XSS, exposed credentials, and browser-based vulnerabilities.

    Frontend Security Matters

    AI-generated frontend code often exposes sensitive data in client-side code, trusts client-side validation, or creates XSS vulnerabilities. Frontend security testing is essential because attackers have full access to inspect and manipulate client-side code.

    Frontend Security Testing Checklist

    Follow these 10 steps for comprehensive frontend security testing. Critical items must be tested before deploying client-facing applications.

    Step 1

    XSS vulnerability testing

    Critical

    Test all input fields and dynamic content rendering for reflected, stored, and DOM-based XSS vulnerabilities.

    Step 2

    Client-side validation bypass

    Critical

    Test that security-critical validation is enforced on the backend and cannot be bypassed through client manipulation.

    Step 3

    Sensitive data exposure

    Critical

    Review client-side code for hardcoded API keys, tokens, credentials, or sensitive business logic.

    Step 4

    CORS policy testing

    Critical

    Verify CORS configuration to ensure only authorized origins can interact with your application.

    Step 5

    Clickjacking protection

    Critical

    Test for X-Frame-Options or CSP frame-ancestors to prevent clickjacking attacks on sensitive pages.

    Step 6

    Content Security Policy

    Verify CSP headers are properly configured to prevent XSS and data injection attacks.

    Step 7

    Local storage security

    Review what data is stored in localStorage and sessionStorage for sensitive information exposure.

    Step 8

    Third-party script review

    Audit all third-party JavaScript libraries and CDN resources for supply chain security risks.

    Step 9

    Authentication token handling

    Verify JWT tokens or session identifiers are not exposed in URLs or insecure storage.

    Step 10

    Postmessage security

    Test postMessage handlers for origin validation and message injection vulnerabilities.

    Common Frontend Vulnerabilities

    DOM-Based XSS

    Critical

    JavaScript code dynamically creates HTML from user input without proper sanitization or encoding.

    Exposed API Keys

    Critical

    API keys, tokens, or credentials hardcoded in client-side JavaScript or HTML source code.

    Client-Side Trust

    High

    Application relies on client-side validation or authorization checks that can be easily bypassed.

    Insecure Dependencies

    High

    Using frontend libraries with known vulnerabilities or outdated packages with security issues.

    Related Resources

    Penetration Testing Guide

    Complete penetration testing methodology

    Code Security Scanning

    Scan JavaScript code for vulnerabilities

    Manual Security Testing

    Manual testing techniques for client-side flaws

    Common Security Flaws

    Most common vulnerabilities in AI-generated code

    Scan Your Frontend Code

    VibeEval automatically scans client-side code for exposed credentials, XSS vulnerabilities, and insecure configurations in your AI-generated applications.

    Start Frontend Security Scan