Cross-Site Scripting (XSS) is a type of cyber attack that involves injecting malicious code, known as a "payload," into a website or web application. The payload is usually in the form of a script, such as JavaScript, and is designed to be executed by the user's web browser when they visit the compromised website or application.
XSS attacks can be used to steal sensitive information from users, such as login credentials or financial information. They can also be used to modify the content or functionality of a website or application, potentially leading to the disruption of services or the spread of misinformation.
There are several ways that attackers may try to exploit XSS vulnerabilities. One common method is to inject a payload into a website or application through a form field or input box. For example, an attacker may try to trick a user into entering a payload into a search field on a website, which is then stored in the website's database and executed whenever the user or another user performs a search.
Another method is to inject a payload into a website or application through a URL parameter. For example, an attacker may create a link to a website that includes a payload in the URL, which is then executed by the user's web browser when they click the link.
To protect against XSS attacks, websites and applications can implement a number of measures, such as input validation and sanitization, which involves checking and cleaning user input to ensure that it does not contain any harmful code. Developers can also use server-side technologies, such as content security policies, to prevent the execution of malicious scripts on the client side.
Overall, XSS attacks can have serious consequences for both individuals and organizations, as they can potentially allow attackers to access or modify sensitive information or disrupt the operation of a website or application. It is important for both users and developers to be aware of this threat and take steps to prevent it.