Best Practices for Report-Only Mode

Best Practices for Report-Only Mode

Implementing Report-Only mode effectively requires following established best practices:

// CSP Report-Only Best Practices Implementation
class CSPReportOnlyBestPractices {
  constructor() {
    this.config = {
      // Minimum report-only duration by environment
      durations: {
        development: 1, // 1 week
        staging: 2, // 2 weeks
        production: 4 // 4 weeks
      },
      
      // Violation thresholds before policy adjustment
      violationThresholds: {
        legitimate: 100, // Consider allowing if >100 violations
        suspicious: 10, // Investigate if 10-100 violations
        rare: 1 // Ignore if <10 violations
      }
    };
  }
  
  generateReportOnlyStrategy(environment) {
    return {
      phases: [
        {
          name: 'Discovery',
          duration: this.config.durations[environment] / 2,
          policy: this.getDiscoveryPolicy(),
          goals: [
            'Identify all resource dependencies',
            'Catalog third-party services',
            'Document inline code usage'
          ]
        },
        {
          name: 'Refinement',
          duration: this.config.durations[environment] / 2,
          policy: this.getRefinementPolicy(),
          goals: [
            'Eliminate false positives',
            'Optimize directive specificity',
            'Test with real user traffic'
          ]
        }
      ],
      
      analysisSchedule: {
        daily: ['Review new violation sources', 'Check for attack patterns'],
        weekly: ['Adjust policy based on violations', 'Review performance impact'],
        beforeEnforcement: ['Final security audit', 'Stakeholder approval']
      }
    };
  }
  
  getDiscoveryPolicy() {
    // Permissive policy for initial discovery
    return [
      "default-src * data: blob: 'unsafe-inline' 'unsafe-eval'",
      "report-uri /csp-discovery-reports"
    ].join('; ');
  }
  
  getRefinementPolicy() {
    // More restrictive policy based on discovery findings
    return [
      "default-src 'self'",
      "script-src 'self' 'unsafe-inline' 'unsafe-eval'", // To be refined
      "style-src 'self' 'unsafe-inline'", // To be refined
      "img-src 'self' data: https:",
      "font-src 'self'",
      "connect-src 'self'",
      "report-uri /csp-refinement-reports"
    ].join('; ');
  }
  
  analyzeReportOnlyResults(violations) {
    const analysis = {
      legitimateSources: [],
      suspiciousSources: [],
      recommendations: []
    };
    
    // Group violations by source
    const sourceGroups = this.groupViolationsBySource(violations);
    
    Object.entries(sourceGroups).forEach(([source, data]) => {
      if (data.count > this.config.violationThresholds.legitimate) {
        analysis.legitimateSources.push({
          source,
          count: data.count,
          directives: data.directives,
          recommendation: `Add ${source} to ${data.directives.join(', ')}`
        });
      } else if (data.count > this.config.violationThresholds.suspicious) {
        analysis.suspiciousSources.push({
          source,
          count: data.count,
          recommendation: 'Investigate necessity before adding to policy'
        });
      }
    });
    
    return analysis;
  }
}

CSP Report-Only mode serves as an essential bridge between security aspirations and practical implementation. By following a structured approach to Report-Only deployment, analysis, and transition, organizations can implement robust Content Security Policies that enhance security without disrupting user experience. The key to success lies in patience, thorough analysis, and gradual enforcement based on real-world data rather than assumptions. Remember that Report-Only mode is not just a testing phase but a valuable ongoing tool for policy maintenance and security monitoring.## Advanced CSP Patterns - Nonces, Hashes, and Strict-Dynamic

Advanced Content Security Policy patterns provide powerful mechanisms for maintaining security while supporting modern web application requirements. Nonces, hashes, and the strict-dynamic keyword represent the cutting edge of CSP implementation, offering solutions that balance security with flexibility. This comprehensive guide explores these advanced patterns, demonstrating how to implement them effectively in production environments.