Cross-Site Scripting (XSS) is a web security vulnerability that allows an attacker to inject malicious scripts in web pages viewed by other users. These scripts may steal sensitive information, hijack user sessions, or send users to malicious websites.
How XSS Works
The most common type of XSS attack is injecting malicious code into a task input field like a comments section, search box or message board. Once a website will receive this input, if the input is not well sanitized or validated, it will run the script on the user browser.
Types of XSS Attacks
Reflected XSS: The malicious script is reflected back from the server to the user’s browser.
Stored XSS: where the attack script is stored on the server and run when a victim accesses the affected page.
DOM XSS: this attack uses the vulnerabilities of the browser to inject malicious scripts into the Document Object Model (DOM)
Protecting Against XSS
Steps to follow to protect a website from XSS attacks?
Validation & Sanitization of Input: Validate & sanitize all input data (User Input/ Site Input/ API Input) to remove or neutralize malicious code.
Output Encoding: Ensure output is encoded so that any injected JavaScript is not recognized as HTML.
Employ a Web Application Firewall (WAF): Use a WAF that enables detection and prevention of XSS attacks.
Maintain Updated Software: Regularly update web frameworks, libraries, and plugins to protect against known vulnerabilities.
Prevention–Dev: Implement secure code–but perhaps that is no longer as critical for future looking systems as we have to accept we are all compromised now.
Security Audits: Perform periodic security audits to detect and eliminate vulnerabilities.
Knowing how XSS attacks work and using strict security measures can help developers eliminate these vulnerabilities and prevent their websites and users from being compromised.
