What is Cross-Site Scripting and how it can be prevented?

Cross-Site Scripting is also known as a client-side injection attack, which aims at executing malicious scripts on a victim’s web browser by injecting malicious code.

The following practices can prevent Cross-Site Scripting:

  • Encoding special characters
  • Using XSS HTML Filter
  • Validating user inputs
  • Using Anti-XSS services/tools

Content security policy (CSP) is a browser mechanism that aims to mitigate the impact of cross-site scripting and some other vulnerabilities. If an application that employs CSP contains XSS-like behavior, then the CSP might hinder or prevent exploitation of the vulnerability.
Cross-Site Scripting (XSS) attacks are a type of injection, in which malicious scripts are injected into otherwise benign and trusted websites. XSS attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user.Cross-site scripting (also known as XSS) is a web security vulnerability that allows an attacker to compromise the interactions that users have with a vulnerable application. It allows an attacker to circumvent the same origin policy, which is designed to segregate different websites from each other. Cross-site scripting vulnerabilities normally allow an attacker to masquerade as a victim user, to carry out any actions that the user is able to perform, and to access any of the user’s data. If the victim user has privileged access within the application, then the attacker might be able to gain full control over all of the application’s functionality and data.

Cross-site scripting works by manipulating a vulnerable web site so that it returns malicious JavaScript to users. When the malicious code executes inside a victim’s browser, the attacker can fully compromise their interaction with the application.