Have you heard of keyloggers? They consist of software that, as the name suggests, is designed to record a user’s keystrokes. Most keyloggers are used for malicious purposes, such as capturing the login credentials of an unsuspecting victim. If your computer is infected with a keylogger, the attacker who deployed it will see every word and letter that you type. While all keyloggers are designed to record keystrokes, though, they are available in different types.

#1) Form Grabbing

Form grabbing is a type of keylogger that’s specifically designed to record data entered into web forms. Web forms are elements on websites that allow visitors to enter data. Some of them are used for logins, whereas others are used for visitor comments. Regardless, a form-grabbing keylogger can see what you enter into these forms. Form-grabbing keyloggers are typically deployed on websites rather than the hosts’ computers.

#2) JavaScript

Different keyloggers use different technologies to record keystrokes. JavaScript keyloggers are characterized by the use of JavaScript. They are written in JavaScript code, which is injected into websites and web pages. Once injected, a JavaScript keylogger will run scripts to record the keystrokes of the website’s or page’s visitors.

#3) Memory Injection

Another common type of keylogger is memory injection. Memory-injection keyloggers are designed to modify the memory tables in a user’s web browser. It’s one of the more technical types of keyloggers. By modifying the memory tables, an attacker can bypass the web browser’s safeguards to eavesdrop on the user’s keyloggers.

#4) API

There are also Application Programming Interface (API) keyloggers. API keyloggers are characterized by the use of an API. They run inside of applications where they are able to record keystrokes. Each time you press a key — or when you release your finger from a key — an event is recorded in the API keylogger.

#5) Hardware

While most keyloggers are software based, some of them are hardware based. Hardware-based keyloggers typically consist of dongles. These dongles may be connected to a Universal Serial Bus (USB) port. Once connected, hardware-based keyloggers will run automatically in the background of the user’s computer while recording his or her keystrokes.

There are different types of keyloggers. As revealed here, some of the most common types include form grabbing, JavaScript, memory injection, API and hardware. Each type works in a different way, but they are all designed to record keystrokes — typically for a malicious purpose like data theft.