Skills Development CORS Policy Validator

CORS Policy Validator

v20260222
validating-cors-policies
Analyzes CORS configurations via the cors-policy-validator plugin to spot misconfigurations, validate headers or files, and report vulnerabilities so developers can secure web apps and APIs from unsafe cross-origin access.
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Overview

Overview

This skill empowers Claude to assess the security and correctness of CORS policies. By leveraging the cors-policy-validator plugin, it identifies misconfigurations and potential vulnerabilities in CORS settings, helping developers build more secure web applications.

How It Works

  1. Analyze CORS Configuration: The skill receives the CORS configuration details, such as headers or policy files.
  2. Validate Policy: It utilizes the cors-policy-validator plugin to analyze the provided configuration against established security best practices.
  3. Report Findings: The skill presents a detailed report outlining any identified vulnerabilities or misconfigurations in the CORS policy.

When to Use This Skill

This skill activates when you need to:

  • Validate a CORS policy for a web application.
  • Check the CORS configuration of an API endpoint.
  • Identify potential security vulnerabilities in existing CORS implementations.

Examples

Example 1: Validating a CORS Policy File

User request: "Validate the CORS policy in cors_policy.json"

The skill will:

  1. Read the cors_policy.json file.
  2. Use the cors-policy-validator plugin to analyze the CORS configuration.
  3. Output a report detailing any identified vulnerabilities or misconfigurations.

Example 2: Checking CORS Headers for an API Endpoint

User request: "Check CORS headers for the API endpoint at https://example.com/api"

The skill will:

  1. Fetch the CORS headers from the specified API endpoint.
  2. Use the cors-policy-validator plugin to analyze the headers.
  3. Output a report summarizing the CORS configuration and any potential issues.

Best Practices

  • Configuration Source: Always specify the source of the CORS configuration (e.g., file path, URL) for accurate validation.
  • Regular Validation: Regularly validate CORS policies, especially after making changes to the application or API.
  • Heuristic Analysis: Consider supplementing validation with manual review and heuristic analysis to catch subtle vulnerabilities.

Integration

This skill can be integrated with other security-related plugins to provide a more comprehensive security assessment. For example, it can be used in conjunction with vulnerability scanning tools to identify potential cross-site scripting (XSS) vulnerabilities related to CORS misconfigurations.

Info
Category Development
Name validating-cors-policies
Version v20260222
Size 2.85KB
Updated At 2026-02-26
Language