Why is JavaScript Vulnerable?

News stories increasingly feature JavaScript security problems. Security professionals are asking “Why is JavaScript vulnerable?”

JavaScript is vulnerable because it is easy for hackers and other threat actors to input query strings into forms to access, steal, or contaminate protected data.

• JavaScript is the standard for the processing of personal information in client-side websites and applications. There are many open-source and third-party libraries available today, the majority of which have known vulnerabilities and are easy for threat actors to infiltrate.
• By default, JavaScript environments do not have a security  permissions model built in. The World Wide Web Consortium standard is that security permissions—what code is able to execute and what types of activities scripts are allowed to do—  are housed in browsers, and the responsibility to manage them lies with the site owner. The onus is on site owners to implement CSP, SRI, & other policies.

Most Common JavaScript Vulnerabilities

The most common JavaScript security vulnerabilities include:

• Source code vulnerabilities
• Input validation
• Reliance on client-side validation
• Unintended script execution
• Session data exposure
• Unintentional user activity

By taking advantage of these vulnerabilities, hackers can leverage JavaScript to engage in malicious activities. Two of the most prominent attack types include cross-site scripting (XSS), which involves client-side code injection enabling threat actors to steal data inputted by the client and cross-site request forgery (CSRF or XSRF), which forces users to execute malicious or unwanted actions on a web application. Other threats include JavaScript sniffers and JavaScript injection attacks. Magecart and e-skimming attacks are also reasons why JavaScript is vulnerable.

Why is JavaScript Security Important?

More than 99% of all websites use JavaScript. Up to 80% of all websites are believed to use a third-party JS library or web framework for their client-side scripting. So, applying JavaScript security best practices is essential.

Learn More

To learn more about JavaScript problems, read the blog How to Check If Your JavaScript Security Is Working. And if you want to learn more about JavaScript security, check out our new e-book The Ultimate Guide to JavaScript Security.