XSS stands for Cross-Site Scripting, which is a type of attack in which an attacker injects malicious code into a website or web application, allowing them to execute arbitrary code in the context of the victim’s browser.
In PHP, XSS attacks occur when an application does not properly sanitize user input and outputs it back to the user without encoding or escaping it. This allows an attacker to inject JavaScript code into the web page, which is then executed by the victim’s browser when they visit the compromised page.
For example, an attacker may craft a malicious link that includes a script tag, which when clicked by the victim, will execute the script and steal their session ID or other sensitive information.
To prevent XSS attacks in PHP, it is important to properly sanitize all user input and output to ensure that any HTML or JavaScript code is encoded or escaped before it is displayed to the user. This can be achieved using PHP’s built-in functions such as htmlspecialchars(), htmlentities(), and strip_tags().
In addition, developers should also use secure cookies, implement content security policies (CSPs), and validate input to ensure that it matches the expected format and does not contain any malicious code.
