If you’ve ever visited a website and noticed an XSS vulnerability, you’ve probably wondered what the attacker’s purpose is. They may want to gather user data, masquerade as the user, or redirect the user to a malicious website. Here’s an example of an XSS attack. You can’t see it, but it works! The attacker simply uses the XSS vulnerability to gain access to sensitive information or redirect a user to an inappropriate website.
Stored and Reflected XSS Attacks
Stored and Reflected XSS attacks are both methods of injecting malicious code into a web application. A stored XSS attack is when the attacker intercepts a legitimate request and adds malicious code to the server. The impact of this attack is greater than a reflected XSS attack, because each user visiting the compromised website will be exposed to the malicious code. This method is especially dangerous when a website allows user sharing.
Types of XSS Vulnerabilities
How to Protect Yourself
XSS, or cross-site scripting vulnerabilities, are attacks that exploit browser weaknesses. They happen when an application uses data from an untrusted source and includes it in an unsafe way. The data could come from an HTTP request, social media post, or network monitoring application. Fortunately, there are many ways to protect yourself from reflected XSS attacks. Encryption, validation, and escaping/encoding techniques can protect your website from this type of attack.
Alternate XSS Syntax
The Alternate XSS Syntax vulnerability affects websites and web applications that store user input. This can be in the form of user-supplied data in a message forum, visitor log, comment field, and other places. The data is then retrieved by the victim through a web application’s request and rendered in the browser. The attacker’s payload may be stored in the browser or HTML5 database and never sent to the target server.