5 Most Reliable Practices to Maintain Angular App Security

5 Most Reliable Practices to Maintain Angular App Security

Published at - Aug 13, 2021

Angular is one of the most famous JavaScript framework for developing single-page web applications. These web apps have proven to be immensely vulnerable to cyberattacks from several sources. So, everyone’s responsibility is to safeguard their data. Here, we will help you build a secure Angular app by providing 5 Most Reliable Practices to Maintain Angular App Security. 

Making the app safe and comprehensive should prioritize every product owner as it is crucial to deliver a tension-free experience to users. Following are the most reliable practices recommended to prevent vulnerabilities in your app.

Avoid Cross-site Scripting (XSS)

Anyone can inject their malicious scripts into DOM elements to steal your website information, like web tokens or essential credentials. There are several ways that cybercriminals can inject their malicious scripts; one such easy is by adding a <script> tag. For example, they might insert text fields or pop-ups to obtain user information. Another menacing malfunction they might implement is to insert <a> tags, which, if a user taps them, will take the user to some inappropriate website.

To prevent such kinds of cruel activities, any values inserted into a page must be sanitized. Unfortunately, angular considers every value as unreliable by default. So, every user’s responsibility is to filter them before they are included.


This process of validating unreliable values depends on various contexts. The security contexts are attributes (binding values), style (CSS), HTML(binding inner HTML), and resources (referring to files). You will have to convert the unreliable values provided by users into reliable values with tools like DomSanitizer.

import { Component, OnInit } from '@angular/core';
import { SecurityService } from './data.service';
import { DomSanitizer, SafeHtml } from '@angular/platform-browser';
  selector: 'app-root',
  template: `<div [innerHtml] = "safeValue"></div>`,
  providers: [SecurityService]
export class AppComponent implements OnInit {
  safeValue: SafeHtml;
  constructor(private secure: SecurityService) {
    this.safeValue = this.secure.getSafeHtml("<h1>Sanitization Success</h1>");
  ngOnInit() {

You have to include a <h1> tag within the div and bind InnerHtml and the SafeValue attribute. It is crucial to use attribute binging while conducting sanitization. So, we pass the HTML string to our service technicians to get a secured value.

Below is the service code, for example, DomSanitizer’ser’s API bypassSecurityHTML for sanitization of the value.

import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs';
import { DomSanitizer } from '@angular/platform-browser';
export class SecurityService {
constructor(private sanitizer: DomSanitizer) {
getSafeHtml(html: string) {
return this.sanitizer.bypassSecurityTrustHtml(html);

At last, a “Sanitization Succes” screen will appear as the output of this sanitized HTML insertion.

Block Vulnerabilities related to HTTP

Cross-site script inclusion (XSSI) and cross-site request forgery(CSRF/XSRF) are the two significant HTTP vulnerabilities that impact the security concerns of an Angular app. But Angular consists of some built-in helpers to avoid them at the client-side itself.

Cross-site Request Forgery

Third-party sites can redirect your users to their websites, which might give them malicious requests to the app server. This method is known as cross-site request forgery (CSRF/XSRF).

Like if you are using a banking app and have tapped on an in-app advertisement by mistake. This will launch a new tab, and that website might ask your banking server to send money to their bank account. If the app is not safe, it would be a considerable risk for your money and data.

To prevent such forgeries, apps must ensure the primary origin of any request, which needs both client-level and server-level security,

The most usual and effective method is sending a confirmation token in the cookie using the server. The client code reads that cookie and adds a customized request header with a token in every subsequent request. Then, the server verifies the received cookie value by comparing it with the request header value and rejecting it if the values do not match or are missing. Since almost every browser applies the same-origin policy, the approach is safe.

Cross-site Script Inclusion (XSSI)

This is another method of cybercriminals stealing user’s data by adding vulnerable scripts in our app. It is also well-known as a JSON vulnerability. Cybercriminals might add an API link using a <script> tag to read app information. But it is only feasible if the JSON is executable. HttpClient library of Angular recognizes this convention and eliminates the string “)]}’,\n” from all responses automatically before further parsing to make it non-executable.

Prevent Risky Angular APIs

Avoid Angular APIs spotted in the documentation as “Security risk.” The most common malicious API you can use is ElementRef. It gives you permission to access the DOM directly and makes your app more vulnerable to XSS threats. Review any ElementRef in your line of code carefully. Use this API as a final resort when you require direct access to the DOM. Use data binding and templating provided by Angular instead.

Alternatively, you can choose Renderer2, which helps you by offering an API that can be used safely even if direct access to native elements is unavailable.

Stay in Touch with Latest Angular Library

Angular regularly upgrades its libraries, which may help you fix security errors discovered in the former versions. Check the Angular changelog for security updates. It’s best practice to level up your app using the latest version.

No Need to Customize Angular Files

The frequent customization of Angular files will make you dependent on the version you have. Probably you will miss the potential security fixes in the later editions. So, advanced practice is to share your enhancements or fixes with the Angular community and create a pull request. Moreover, your modifications might override the existing behavior and lead to a few security concerns.


Here, we have discussed how to build a secure Angular app and the best practices to prevent vulnerabilities in it. Then, you can implement them to provide a quality user experience without disturbing the algorithm of your app development process.

angular best practices, angular app, angular application, angular web app, angular building, app development app

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About author

Harendra Kanojiya

Hello, I am Harendra Kumar Kanojiya - Owner of this website and a Fullstack web developer. I have expertise in full-stack web development using Angular, PHP, Node JS, Python, Laravel, Codeigniter and, Other web technologies. I also love to write blogs on the latest web technology to keep me and others updated. Thank you for reading the articles.

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