Web Security


Formjacking is a cyberattack in which malicious actors compromise a website's payment or data entry forms to steal sensitive information, such as credit card details, without the user's knowledge.

Attackers inject malicious code into the website's code, intercepting data entered by visitors.

What is formjacking?

Formjacking works by exploiting vulnerabilities in a website's code or infrastructure and retrieving data.

This stolen information is then used for fraudulent activities or sold on the dark web. Formjacking poses a significant threat to online security and privacy, making it crucial for websites to implement strong cybersecurity measures to prevent such attacks.

How does it work?

Here’s how it usually works: 

  • Attackers seek out websites with security weaknesses or vulnerabilities that can be exploited. These vulnerabilities might be in the website's code, content management system, or third-party code that’s running on the website;

  • Once a vulnerability is identified, the attacker injects malicious JavaScript code into the website's codebase. This code is often designed to run silently in the background;

  • The injected code intercepts user input data, such as credit card numbers, personal information, and/or login credentials, when visitors enter it into online forms on the compromised website;

  • The stolen data is then sent to a server controlled by the attacker, where it is collected and stored for illicit purposes;

  • The formjacking attack can continue undetected, compromising data from multiple website visitors over an extended period, allowing attackers to gather a significant amount of sensitive information.

How to detect and prevent formjacking?

To detect and prevent formjacking, some security measures can be put in place. It’s important to regularly update the website's software, plugins, and extensions to fix any potential weaknesses and make sure the website uses a secure connection (HTTPS) to keep data safe during transmission.

Setting up the Content Security Policy (CSP) helps stop unauthorized code from running on your site by specifying which domains are allowed to execute scripts.

The website should be regularly scanned for vulnerabilities and odd activities, as well as the server logs. Using a Web Application Firewall (WAF) is also a form of prevention, as it can filter out and block malicious traffic.

Preventing formjacking is synonymous with analyzing the source code of the website. Anything related to forms and data submission has to be checked out frequently so that any vulnerabilities can be detected and fixed.

How Jcrambler can help you

Prevent client-side attacks with Jscrambler’s security platform

Recommended to read next

Web Security

Client-side Security

Web applications' client-side security has been a low priority for businesses, increasing opportunities for threat actors to exploit end-user activities.

8 min read

Read More
Web Security

Web Application Security

Magecart attack refers to the methods, technologies, or processes for protecting web applications from cyber attacks by Internet-based threats.

6 min read

Read More