What is Cross-Site Scripting (XSS)?
Cross-Site Scripting, abbreviated as XSS, is one of the most common security vulnerabilities affecting web applications. In XSS, attackers exploit websites by injecting malicious scripts into content that is viewed by other users. These scripts can be written in various languages, most commonly in JavaScript.
Types of Cross-Site Scripting
There are several types of Cross-Site Scripting, each using different methods:
Reflected XSS
Reflected XSS occurs when user data is immediately embedded into the HTTP response without being cached or stored. This type of attack is often spread through malicious links.
Stored XSS
Stored XSS, also known as persistent XSS, saves the malicious data on the server. These scripts are delivered to multiple users each time the vulnerable page is viewed.
DOM-based XSS
DOM-based XSS occurs when the client-side code of the web application allows the execution of malicious scripts in the browser without requiring server interaction.
Risks of Cross-Site Scripting
The risks posed by XSS are significant, as attackers can gain access to user information such as cookies, session IDs, and other sensitive information. Furthermore, attackers can steal login credentials, introduce malicious code, and redirect users to phishing websites.
Protective Measures against Cross-Site Scripting
To protect your application from XSS attacks, you should take the following measures:
✔ Validate and sanitize inputs: Ensure that all user inputs are validated and sanitized before being integrated into the application. ✔ Use HTTP-Only and Secure flags: Set HTTP-Only and Secure flags on cookies to prevent them from being read by malicious scripts. ✔ Implement a Content-Security-Policy (CSP): Employ a Content-Security-Policy to regulate which resources are allowed to be loaded or executed from a page.
Have your systems tested for XSS vulnerabilities
Regular security testing is essential to identify and remediate potential XSS vulnerabilities.
Related Terms and Further Topics
📌 Related Terms: Web Application Firewalls (WAF), vulnerabilities in web applications, security testing
Cross-Site Scripting is a serious security risk that can significantly compromise the integrity of web applications. By understanding the risks and implementing comprehensive security measures, organizations can better protect their web applications.
