What are some ways to secure an Angular application?

There are many ways to secure Angular apps. Hire Angular developers with proficiency in following client-side best practices. They should also be well-verse in providing security measures to protect users and limit exposures to attacks.

Here’s a deep dive into Angular security best practices, along with examples and why each is important:

Use Angular’s Built-in Sanitization

What: Angular automatically sanitizes values bound to the DOM (especially in [innerHTML]) to prevent Cross-Site Scripting (XSS).

Why: Cross-Site Scripting attacks inject malicious scripts to the target app. Angular DOM sanitizer filters untrusted values and ensures they are free from any malware before allowing them to interact with the DOM.

Example:

@Component({ selector: 'app-safe-html', template: `<div [innerHTML]="trustedHtml"></div>`
})
export class SafeHtmlComponent { htmlSnippet = '<script>alert("xss")</script>'; trustedHtml = this.sanitizer.bypassSecurityTrustHtml(this.htmlSnippet); // Only if you trust the source constructor(private sanitizer: DomSanitizer) {}
}

Don’t use bypassSecurityTrustHtml unless you absolutely trust the content. Otherwise, Angular will sanitize dangerous tags like

Use Route Guards to Protect Routes

What: Make use of Angular route guards (CanActivate, CanLoad, etc.) for preventing unauthorized access to certain parts of your application.

Why: It prevents unauthorized navigation by users (e.g., admin pages).

Example:

@Injectable({ providedIn: 'root' })
export class AuthGuard implements CanActivate { constructor(private auth: AuthService, private router: Router) {} canActivate(): boolean { if (this.auth.isLoggedIn()) { return true; } else { this.router.navigate(['/login']); return false; } }
}

Route config

{ path: 'dashboard', component: DashboardComponent, canActivate: [AuthGuard] }

Don’t Use LocalStorage or SessionStorage for Sensitive Data Storage

What: Do not store tokens, passwords, or personal user info in localStorage or sessionStorage.

Why: They are accessible via JavaScript and can be compromised in an XSS attack.

Better Practice: Use HttpOnly cookies (set via server) to store authentication tokens. These are not accessible via JavaScript.
// Don’t do this:

localStorage.setItem('token', 'eyJhbGciOiJI...');

Do this on the backend:

Set-Cookie: token=jwt-token; HttpOnly; Secure; SameSite=Strict

Follow Content Security Policy (CSP)

What: Configure your web server to send a CSP header that limits what content can be loaded (scripts, styles, images, etc.).

Why: It helps overcome cross-site scripting and code injection attacks by limiting allowed sources.

Example:

Content-Security-Policy: default-src 'self'; script-src 'self'; style-src 'self'

Use HTTPS for All Communications

What: Always use https:// for all APIs and your Angular application.

Why: This encrypts communication between your app and the backend, to get protection against Man-In-The-Middle (MITM) attacks. Most browsers now block features like geolocation, service workers, and PWA features on HTTP.

Escape User Input in Templates

What: Avoid direct DOM manipulation or injecting dynamic content without sanitization.
Why: It’s another protection layer against XSS.

Bad Example (Don’t do this):

document.getElementById('msg')!.innerHTML = userInput;

Instead, let Angular handle it with property bindings:

<div>{{ userInput }}</div>

Implement Role-Based Authorization

What: Use roles/claims from your backend (e.g., from JWT or OAuth) and check those on both client and server sides.
Why: You might allow all logged-in users to access the dashboard, but only admins should see admin controls.

Example:

canActivate(): boolean { const user = this.authService.getCurrentUser(); return user && user.roles.includes('admin');
}

Keep Dependencies Updated

What: Regularly update Angular and third-party libraries.
Why: Outdated libraries may contain security vulnerabilities. Use tools like:

npm audit fix
npm outdated

Use Angular’s HttpClient with Interceptors

What: Use HttpInterceptor to inject authentication tokens securely and consistently.
Example:

@Injectable()
export class TokenInterceptor implements HttpInterceptor { constructor(private auth: AuthService) {} intercept(req: HttpRequest<any>, next: HttpHandler) { const token = this.auth.getToken(); const cloned = req.clone({ headers: req.headers.set('Authorization', `Bearer ${token}`) }); return next.handle(cloned); }
}

Lazy Load Sensitive Modules

What: Only load modules like /admin or /user-dashboard after a route guard is passed.

Why: Reduces attack surface and ensures sensitive code is not bundled unnecessarily.

Server-Side Validation (ALWAYS)

What: Never trust client-side validation alone. Always validate and sanitize on the backend.

Conclusion

Secure an Angular app to protect user data and malware or cyber attacks. Follow best practices for Angular development like using in-built sanitization, route guards, HTTPS and server-side validation.