name: validating-cors-policies
description: Validate CORS policies for security issues and misconfigurations. Use when reviewing cross-origin resource sharing. Trigger with 'validate CORS', 'check CORS policy', or 'review cross-origin'.
version: 1.0.0
allowed-tools:
- Read
- WebFetch
- WebSearch
- Grep
license: MIT
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
- Analyze CORS Configuration: The skill receives the CORS configuration details, such as headers or policy files.
- Validate Policy: It utilizes the cors-policy-validator plugin to analyze the provided configuration against established security best practices.
- 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:
- Read the
cors_policy.json file.
- Use the cors-policy-validator plugin to analyze the CORS configuration.
- 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:
- Fetch the CORS headers from the specified API endpoint.
- Use the cors-policy-validator plugin to analyze the headers.
- 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.
Prerequisites
- Access to codebase and configuration files in {baseDir}/
- Security scanning tools installed as needed
- Understanding of security standards and best practices
- Permissions for security analysis operations
Instructions
- Identify security scan scope and targets
- Configure scanning parameters and thresholds
- Execute security analysis systematically
- Analyze findings for vulnerabilities and compliance gaps
- Prioritize issues by severity and impact
- Generate detailed security report with remediation steps
Output
- Security scan results with vulnerability details
- Compliance status reports by standard
- Prioritized list of security issues by severity
- Remediation recommendations with code examples
- Executive summary for stakeholders
Error Handling
If security scanning fails:
- Verify tool installation and configuration
- Check file and directory permissions
- Validate scan target paths
- Review tool-specific error messages
- Ensure network access for dependency checks
Resources
- Security standard documentation (OWASP, CWE, CVE)
- Compliance framework guidelines (GDPR, HIPAA, PCI-DSS)
- Security scanning tool documentation
- Vulnerability remediation best practices