Cross-Site Scripting (XXS Flaws)

Cross-Site Scripting, abbreviated as XSS, is a type of cyberattack that uses injection.

The cyberattacker’s scripts are cleverly fed to a trusted web site, maybe your business’s website, and then spit out to your visitors’ computers, which execute the malicious code because they have no way of knowing not to trust the script.

More specifically, the XSS attack is usually some malicious JavaScript code accepted by a web application on your website that asks for, receives, and processes user data. That’s the cyberattacker’s way in.

The code itself is usually some kind of script that tells your website to send it out to other visitors, who could be your customers or employees. Once sent back out from your website, it runs on their browsers to steal information or hijack their computers for the cyber attacker’s use.

The flaws in your website design that allow this kind of attack to work are very widespread on the Internet and are possible anywhere that a web application uses input from a site visitor within some kind of output that it generates and does not validate or encode the input.

Because your visitors’ computers think the script came from a benign source, the malicious code can access any cookies, hijack user sessions, or find sensitive information stored in the browser and used with your website.

These scripts are really tricky! They can even rewrite the content of the HTML on your page so that it appears differently to your website’s visitors and makes them think you’re telling them or asking them something that you are not.

XSS vulnerabilities can be extremely difficult to detect and remove from a web application. The best way to find an XSS flaw is to conduct a professional security sweep of your website’s code and analyze all functions in which input from an HTTP request could possibly make its way into the HTML output.