Cross-Site Scripting (XSS) is a type of computer security vulnerability where attackers inject malicious scripts into trusted websites and web applications that are accessed by unsuspecting users. These scripts are usually executed within the user's web browser, allowing the attacker to perform various malicious activities, such as stealing sensitive information, spreading malware, manipulating website content, or even taking control of the user's session.
XSS attacks typically occur when web applications do not properly sanitize user-generated input, especially when it is displayed on web pages without validation or proper encoding. Attackers exploit this vulnerability by injecting malicious scripts, often in the form of HTML, JavaScript, or other scripting languages, into the website's input fields, comment sections, or URLs. When the vulnerable page is viewed by another user, the injected script is executed within their browser, leading to unintended consequences.
There are several types of XSS attacks, including stored XSS (where the malicious code is permanently stored on the target server), reflected XSS (where the malicious code is embedded in a URL that the victim clicks on, and the script gets executed on the server side), and DOM-based XSS (where the script manipulates the Document Object Model of the web page, causing it to execute unintended actions).
To prevent XSS attacks, developers should implement proper input validation and output encoding techniques. This includes validating and sanitizing user input, encoding any user-generated data before displaying it on web pages, and implementing strict content security policies. Regular security audits, patching vulnerabilities, and keeping up with the latest security guidelines are essential in maintaining a secure web application environment.
