This document outlines the comprehensive security measures implemented in the Network Scanner tab.

• All inputs validated for correct type (string, number)
• No loose equality or implicit type coercion

• Regex pattern: ^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$
• Validates strict IPv4 format (e.g., 192.168.1.1)
• Rejects incomplete IPs, non-numeric characters

• Whitelist of valid subnet masks only
  • 255.0.0.0
  • 255.255.0.0
  • 255.255.255.0
  • 255.255.255.128, .192, .224, .240, .248, .252, .254, .255

• Range: 1-65535 (valid port range)
• Start port <= end port requirement
• Type validated as integer

• Range: 100-5000 milliseconds
• Prevents DOS with extremely high/low values

• Range: 1-50 threads
• Prevents resource exhaustion

• Regex pattern for valid domain names
• Prevents special characters
• Max length: 255 characters

Blocks dangerous patterns:

• Shell metacharacters: ;, &, |, `, $, (, )
• Path traversal: ../
• System paths: /etc/, /proc/
• Windows commands: cmd.exe, powershell, bash

• Escapes leading characters: =, +, -, @
• Escapes double quotes with ""
• Prevents CSV injection attacks

• Uses textContent instead of innerHTML for user-controlled data
• Manually constructs DOM with createElement()
• HTML escaping function:

  & → &
  < → &lt;
  > → &gt;
  " → &quot;
  ' → &#039;

• All hostnames escaped before rendering
• All IP addresses escaped (defense in depth)
• Port numbers converted to string and joined safely

• Window: 1 second
• Max Requests: 5 per second per user
• Prevents: DOS attacks, spam scanning

if (!SecurityManager.checkRateLimit('scanner')) {
    // Reject scan request
    // Log security event
}

1. SCAN_INITIATED - Scan started with parameters
2. SCAN_RESULTS_DISPLAYED - Results shown to user
3. CSV_EXPORT - Data exported
4. INVALID_INPUT - Bad input received (reason logged)
5. INJECTION_ATTEMPT - Malicious pattern detected
6. RATE_LIMIT_EXCEEDED - Too many requests
7. SCAN_ERROR - Error occurred during scan
8. CSV_EXPORT_ERROR - Export failed
9. SCANNER_RATE_LIMIT - Rate limit triggered

Each entry contains:

• Timestamp (ISO 8601)
• Event type
• Details (JSON stringified)
• User agent
• Limited to 1000 most recent entries

SecurityManager.getAuditLog() // Returns filtered log
SecurityManager.clearAuditLog() // Clears log

• Error text escaped before display
• No stack traces shown to user
• Detailed errors logged only in console/audit

• Safe HTML construction
• Clear error styling
• No dangerous content rendering

• Values escaped for formula injection
• Quotes properly escaped
• Safe file download with cleanup
• Blob-based download prevents URL exposure

• No sensitive system paths exposed
• Port numbers only (no service names)
• Hostnames (if resolved) are safe
• MAC addresses disabled for security

• IP Range: Full subnet (256 IPs)
• Port Range: 1-65535 (customizable per-scan)
• Threads: 1-50 (parallel scanning)
• Timeout: 100-5000ms per IP
• Max Results: Unlimited (filtered UI display)

• Audit log capped at 1000 entries
• Results held in memory only during session
• File downloads use Blob API
• URL objects properly revoked

• ✓ Ping hosts (ICMP)
• ✓ Check common ports
• ☐ Resolve hostnames (DNS)
• ☐ Get MAC addresses (disabled)

Each feature requires explicit user consent

• Trimmed whitespace
• Type validation on form inputs
• Disabled buttons during active scan
• Clear visual feedback

• Online/offline status badges
• Color-coded results
• Progress bar with percentage
• Real-time statistics

• Strict input validation
• Type checking
• Regex pattern matching
• Whitelist approach (subnet masks)
• Command injection prevention
• CSV formula injection prevention
• XSS prevention (textContent, createElement)
• HTML escaping
• Rate limiting
• Audit logging
• Error sanitization
• Resource limits
• Safe file downloads
• Memory management
• User consent for features

// Test injection attempts
testInputs = [
    '192.168.1.1; rm -rf /',
    '192.168.1.1` cat /etc/passwd `',
    '192.168.1.1$(whoami)',
    '=2+5',  // CSV injection
    '<img src=x onerror=alert()>'  // XSS
];

// Trigger rate limiting
for (let i = 0; i < 10; i++) {
    scanBtn.click(); // Should be blocked after 5
}

// Verify logging
console.log(SecurityManager.getAuditLog());

1. Defense in Depth - Multiple validation layers
2. Whitelist Approach - Allow only known-good values
3. Fail Secure - Errors reject input, not accept it
4. Minimal Disclosure - Users see safe, generic error messages
5. Audit Trail - All security events logged
6. Input Validation - Strict before processing
7. Output Encoding - Safe before display
8. Resource Limits - Prevent DOS attacks
9. User Consent - Optional features require user choice
10. Code Review Ready - Clear, documented security code

This implementation follows:

• OWASP Top 10 protection principles
• CWE (Common Weakness Enumeration) guidelines
• Electron Security Best Practices
• CSP (Content Security Policy) concepts

• Review audit logs weekly
• Check for attack patterns
• Update validation patterns quarterly
• Test injection attempts monthly

• Keep Node.js updated
• Keep Electron updated
• Update security patterns
• Review new CVEs
• Test with new attack vectors

For security issues or vulnerabilities:

1. Document the issue
2. Check audit logs
3. Review validation logic
4. Test with safe inputs
5. Contact maintainers

Do not publicly disclose security vulnerabilities.