Web applications are broadly popular nowadays. It is easier to find customers and users for your applications on the web as almost everyone has an internet connection and access to the web. 

Approximately 4.93 billion people have an internet connection that makes up 63.2% of the world population.

Source: BroadbandSearch

This is the reason web application development is a prominent part of the IT industry.

Such vastly popular technology also brings attention to malicious elements. Web application security attacks are becoming frequent. One such example of cyber threats to websites or applications is XSS Attacks. 

In this blog, we will go through this code injection attack in detail and answer the following questions:

1. What is XSS Attack all about?
2. What are the different kinds of XSS attacks?
3. How to prevent sites/applications from XSS attacks?

What is an XSS attack?

Cross-site scripting (XSS) attack is a common type of code injection attack that targets web applications by detecting their vulnerabilities and injecting malicious code. In this attack, web applications are not directly affected. Instead, the users who interact with such sites or applications are the potential target. 

The XSS attack occurs when a hacker sends a malicious code to the victim via a web application using the browser-side script style. Attackers take the advantage of web application vulnerabilities found to cause a successful attack.

Types of XSS Attacks

XSS attacks of three types:

• Stored XSS
• Reflected XSS
• DOM Based XSS

1. Stored XSS

Stored XSS is the most damaging vulnerability. This attack occurs when the malicious data payload provided by the attacker is saved on the server. This payload is permanently exposed to the webpage and gets triggered when the user performs regular browsing operations.

2. Reflected XSS

This common cross-site scripting vulnerability is generated when the data provided by the users, usually via HTTP query parameters (example., a form submission) is displayed on the page without properly being filtered or stored.

3. DOM Based XSS

DOM Based on XSS attacks is a type of Cross-site scripting vulnerability that occurs when JavaScript obtains data from an attacker’s regulated source and passes it to modify the DOM environment. This makes the victim’s browser run unexpectedly.

Prevention Against XSS Attacks

The applications can be challenging concerning their complexity. Therefore, it is difficult to secure them from XSS attacks. But with proper prevention measures, you can safeguard your web application from these attacks.

• Must filter out the input received from the user-end.
• At the output, encode the output data to restrict them from signifying as active by implementing combinations of HTML, URL, JavaScript, and CSS encoding.
• You can scan your web application for the potential XSS vulnerabilities using web vulnerability scanner tools.
• Implement proper response headers and block XSS in HTTP responses that are not expected to include any HTML or JavaScript and make sure that browsers execute the intended response.
• You can also implement Content Security Policy (CSP) to subdue the dreadful impact of any other XSS vulnerabilities.

In the End

To know more about the XSS attacks and other web application attacks, you can pursue the Web Application Security Certified Professional course by Krademy.