Version: 2.901.0
Last Updated: April 2026
Security Contact: GitHub Issues

FinBuddy with KautilyaAI takes security seriously. This document outlines our comprehensive security practices, vulnerability reporting process, and data protection measures for both financial data and AI interactions.

FinBuddy implements multiple layers of security to protect user financial data and ensure secure AI interactions:

• End-to-End Encryption: All data encrypted in transit (HTTPS) and at rest (Firebase)
• Local-First Architecture: Data processed locally with cloud sync, not cloud-dependent
• User Isolation: Complete data separation between users via Firebase security rules
• Zero-Knowledge: We cannot access your personal financial data
• AI Data Protection: KautilyaAI interactions are processed securely without storing personal conversations

• Secure AI Processing: Google Gemini 2.0 Flash with enterprise-grade security
• Data Minimization: Only necessary financial context shared with AI, no personal identification
• Wisdom-Only Mode: Currently operates in READ-only mode for enhanced data safety
• Firebase Functions v2: Modern serverless security with CORS protection
• API Key Protection: Gemini API keys secured via Firebase secrets management
• Context Isolation: User financial data processed in isolated function environments

• OAuth 2.0: Secure Google authentication with industry standards
• Token Management: Automatic token refresh with secure local storage
• Session Security: Configurable timeout and automatic logout
• Multi-Factor Ready: Framework supports 2FA implementation
• Firebase Auth: Enterprise-grade authentication with security rules

• XSS Protection: React's built-in XSS prevention + Content Security Policy
• CSRF Protection: Firebase SDK handles CSRF token validation
• PWA Security: Service Worker with integrity checks and secure caching
• HTTPS Only: All connections require SSL/TLS encryption
• Input Sanitization: All user inputs sanitized before AI processing

• Prompt Injection Protection: Advanced validation prevents malicious AI prompts
• Response Filtering: AI responses filtered for inappropriate content
• Rate Limiting: Prevents abuse of AI endpoints
• Audit Logging: All AI interactions logged for security monitoring
• Error Handling: Secure error messages without exposing system details

We take security vulnerabilities seriously and appreciate responsible disclosure.

🚨 For Security Issues - DO NOT use public GitHub issues

1. Email: Create a GitHub issue with [SECURITY] prefix (for non-critical issues)
2. Critical Issues: Email repository maintainers directly via GitHub profile
3. Emergency: For immediate threats, create urgent GitHub issue

Please provide detailed information to help us understand and resolve the issue:

📋 **Vulnerability Report Template**

**Vulnerability Type**: (e.g., Authentication bypass, XSS, Data exposure)
**Severity Level**: Critical / High / Medium / Low
**Affected Component**: (Frontend, Firebase rules, Authentication, etc.)
**Attack Vector**: (Local, Network, Remote)

**Description**:
[Clear description of the vulnerability]

**Steps to Reproduce**:
1. Step one
2. Step two
3. Step three

**Impact**:
[Potential impact and what an attacker could achieve]

**Proof of Concept**:
[Screenshots, code snippets, or demonstration (if safe)]

**Suggested Fix**:
[If you have suggestions for remediation]

**Environment**:
- Browser: [Chrome 91, Firefox 89, etc.]
- OS: [Windows 10, macOS 11, etc.]
- App Version: [2.2.1]
- Firebase Environment: [Production, Development]

• Authentication bypass allowing unauthorized access
• Remote code execution
• Mass data exposure
• Financial data theft vectors

• Privilege escalation
• Stored XSS in core features
• User data exposure
• Session hijacking

• Reflected XSS
• CSRF in non-critical functions
• Information disclosure (non-sensitive)
• Rate limiting bypass

• UI/UX security improvements
• Non-exploitable information disclosure
• Security header optimizations
• Development environment issues

// vite.config.ts - Security headers
export default defineConfig({
  server: {
    headers: {
      'Content-Security-Policy': [
        "default-src 'self'",
        "script-src 'self' 'unsafe-inline' https://apis.google.com",
        "style-src 'self' 'unsafe-inline' https://fonts.googleapis.com",
        "font-src 'self' https://fonts.gstatic.com",
        "img-src 'self' data: https://firebasestorage.googleapis.com",
        "connect-src 'self' https://*.googleapis.com https://api.openai.com"
      ].join('; ')
    }
  }
});

• Type Safety: TypeScript prevents type-related vulnerabilities
• Form Validation: Zod schema validation on all user inputs
• XSS Prevention: React's automatic escaping + DOMPurify for HTML content
• SQL Injection: N/A (NoSQL Firestore with parameterized queries)

// Example: Secure expense input handling
const addExpense = async (expense: ExpenseInput) => {
  // 1. Type validation
  const validatedExpense = ExpenseSchema.parse(expense);
  
  // 2. User authentication check
  if (!user?.uid) throw new Error('Authentication required');
  
  // 3. Input sanitization
  const sanitizedDescription = DOMPurify.sanitize(validatedExpense.description);
  
  // 4. Firestore security rules handle authorization
  await addDoc(collection(db, 'users', user.uid, 'expenses'), {
    ...validatedExpense,
    description: sanitizedDescription,
    userId: user.uid, // Explicit user association
    createdAt: serverTimestamp()
  });
};

// Comprehensive security rules
rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    // User data isolation
    match /users/{userId}/{document=**} {
      allow read, write: if request.auth != null && 
        request.auth.uid == userId &&
        isValidUserData(resource.data);
    }
    
    function isValidUserData(data) {
      return data.keys().hasAll(['userId']) &&
        data.userId == request.auth.uid;
    }
  }
}

// File upload security
rules_version = '2';
service firebase.storage {
  match /b/{bucket}/o {
    match /receipts/{userId}/{receiptId} {
      allow read, write: if request.auth != null && 
        request.auth.uid == userId &&
        // File size limit (10MB)
        request.resource.size < 10 * 1024 * 1024 &&
        // Image files only
        request.resource.contentType.matches('image/.*') &&
        // Filename validation
        receiptId.matches('^[a-zA-Z0-9._-]+$');
    }
  }
}

// Secure authentication setup
const auth = getAuth(app);
const provider = new GoogleAuthProvider();

// Security-focused OAuth scopes
provider.addScope('profile');
provider.addScope('email');
// Note: We do NOT request financial data scopes

// Secure sign-in with popup
const signInWithGoogle = async () => {
  try {
    const result = await signInWithPopup(auth, provider);
    const user = result.user;
    
    // Verify token integrity
    const token = await user.getIdToken();
    if (!token) throw new Error('Authentication failed');
    
    // Log security event
    console.log('Secure authentication successful');
  } catch (error) {
    console.error('Authentication error:', error);
    throw error;
  }
};

• Automatic Token Refresh: Firebase SDK handles token lifecycle
• Secure Token Storage: Tokens stored in Firebase-managed secure storage
• Session Timeout: 1 hour default with automatic refresh
• Logout on Suspicion: Automatic logout on security events

• Dynatrace Integration: Application performance and security monitoring
• Error Tracking: Real-time error reporting with security context
• Authentication Monitoring: Failed login attempts and suspicious activity
• API Rate Limiting: Prevent abuse and DoS attacks

// Security event logging
const logSecurityEvent = (event: SecurityEvent) => {
  // Local logging (development)
  console.log(`[SECURITY] ${event.type}: ${event.description}`);
  
  // Production monitoring (Dynatrace)
  if (process.env.NODE_ENV === 'production') {
    sendToDynatrace({
      source: 'budget-buddy-security',
      event_type: event.type,
      severity: event.severity,
      user_id: event.userId,
      timestamp: new Date().toISOString(),
      details: event.details
    });
  }
};

# GitHub Actions security workflow
name: Security Audit
on: [push, pull_request]
jobs:
  security:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Run npm audit
        run: npm audit --audit-level=moderate
      - name: Check dependencies
        run: npm audit fix --dry-run
      - name: Security linting
        run: npm run lint:security

# .env.example - Template for secure configuration
# Never commit actual values!

# Firebase Configuration (Public - OK to expose)
VITE_FIREBASE_API_KEY=your-firebase-api-key
VITE_FIREBASE_AUTH_DOMAIN=your-project.firebaseapp.com
VITE_FIREBASE_PROJECT_ID=your-project-id

# Sensitive Keys (Keep Secret)
VITE_OPENAI_API_KEY=your-openai-key
VITE_DYNATRACE_TOKEN=your-dynatrace-token

# Production Security
VITE_ENVIRONMENT=production
VITE_ENABLE_ANALYTICS=true
VITE_SECURITY_LOGGING=true

# Security checks for development
npm run security:audit    # Dependency vulnerability scan
npm run security:lint     # Security-focused linting
npm run security:test     # Security unit tests
npm run security:check    # Complete security check

1. 🔒 Use Strong Passwords: For your Google account (we use Google OAuth)
2. 🔐 Enable 2FA: On your Google account for additional security
3. 🌐 Use HTTPS: Always access via https://finbuddy-2025.web.app
4. 📱 Keep Updated: Use latest browser versions for security patches
5. 🚫 Avoid Public WiFi: For financial data access when possible

1. 🔑 Secure API Keys: Never commit secrets to version control
2. 🛡️ Input Validation: Validate all user inputs on both client and server
3. 🔒 Follow Principle of Least Privilege: Minimal permissions required
4. 📝 Security Reviews: Review all security-related code changes
5. 🔄 Regular Updates: Keep dependencies updated and audit regularly

1. 🌐 HTTPS Only: Enforce SSL/TLS for all connections
2. 🔒 Environment Isolation: Separate dev/staging/prod environments
3. 📊 Monitor Security: Set up alerts for suspicious activities
4. 🔄 Regular Backups: Automated backups with encryption
5. 🛡️ Security Headers: Implement comprehensive security headers

1. 🔍 Detection: Automated monitoring or user reports
2. 🚨 Assessment: Evaluate severity and impact
3. 🛡️ Containment: Immediate measures to prevent further damage
4. 🔧 Remediation: Fix the vulnerability and deploy patches
5. 📊 Communication: Update affected users and stakeholders
6. 📝 Post-Mortem: Document lessons learned and improve processes

• Project Maintainer: GitHub Profile
• Security Issues: Create GitHub issue with [SECURITY] prefix
• Critical Vulnerabilities: Email via GitHub profile contact

• OWASP Top 10
• Firebase Security Guidelines
• React Security Best Practices
• TypeScript Security

• Firebase Setup Guide - Secure Firebase configuration
• Deployment Guide - Secure deployment practices
• Observability Guide - Security monitoring setup

• GDPR Ready: Data export, deletion, and portability features
• CCPA Compliant: California Consumer Privacy Act compliance
• SOC 2: Firebase infrastructure meets SOC 2 standards
• ISO 27001: Firebase certified for information security management

• OWASP Compliance: Following OWASP guidelines for web application security
• OAuth 2.0 / OpenID Connect: Industry-standard authentication protocols
• TLS 1.3: Latest encryption standards for data in transit
• AES-256: Advanced encryption for data at rest

FinBuddy is committed to protecting user financial data through:

• ✅ Privacy by Design: Data minimization and user control
• ✅ Security by Default: Secure configurations out of the box
• ✅ Transparent Security: Open source code for security review
• ✅ Continuous Improvement: Regular security updates and patches
• ✅ Responsible Disclosure: Clear vulnerability reporting process

Last Security Review: August 2025 (v2.5.1)
Next Scheduled Review: November 2025 (v2.6.0)
Security Contact: GitHub Issues