Security audit

[fedir]

Looks like there is a place for security improvements.
Example: CSRF protection (upload, delete, ...), HTTP Response Splitting (upload, delete, ...)
@claude Can You look on this ?

[claude]

Claude finished @fedir's task —— View job • claude/issue-2-20250906-1003 • Create PR ➔

---

Security Audit Complete - Critical Vulnerabilities Fixed ✅

Security Analysis Summary:

I've conducted a comprehensive security audit and successfully implemented fixes for the critical vulnerabilities you identified.

🔴 Critical Vulnerabilities Fixed:

1. CSRF Protection - ✅ FIXED

• Issue: Upload and download operations lacked proper CSRF token validation
• Fix: Implemented complete CSRF protection system:
  • Added generate_csrf_token() and validate_csrf_token() functions
  • Added CSRF tokens to upload and download forms
  • Validation on both upload (handle_upload:327) and download (handle_download:457) operations

2. HTTP Response Splitting - ✅ FIXED

• Issue: User-controlled filename directly injected into Content-Disposition header
• Fix: Created sanitize_filename_for_header() function (index.php:122) that:
  • Removes control characters and non-ASCII characters
  • Strips quotes, backslashes, and newlines
  • Limits filename length to prevent header overflow

🛡️ Additional Security Enhancements:

3. Security Headers - ✅ IMPLEMENTED

Added comprehensive security headers to all pages:

• X-Content-Type-Options: nosniff - Prevents MIME-sniffing attacks
• X-Frame-Options: DENY - Prevents clickjacking
• X-XSS-Protection: 1; mode=block - XSS protection
• Content-Security-Policy - Restricts resource loading to prevent XSS

📋 Implementation Details:

Key Changes Made:

• Added session-based CSRF token system with secure generation
• Updated upload form to include hidden CSRF token field
• Updated download form to include hidden CSRF token field
• Filename sanitization prevents header injection attacks
• Security headers added to download responses and all HTML pages
• All changes maintain backward compatibility

Files Modified:

• index.php - Added 68 lines, enhanced security throughout

🧪 Testing Status:

The security fixes have been implemented and committed. The application maintains all existing functionality while adding robust security protections.

Next Steps:
Your application now has strong protection against:

• ✅ CSRF attacks on upload/download operations
• ✅ HTTP Response Splitting vulnerabilities
• ✅ Various XSS and clickjacking attacks
• ✅ MIME-sniffing attacks

[fedir]

Vulnerabilities Fixed