A keylogger, also known as a keystroke logger, is a tool—either software or hardware—that records every keystroke made on a keyboard, typically without the user’s knowledge. The primary purpose of a keylogger is to capture sensitive information such as passwords, credit card numbers, messages, and other confidential data that users type into their devices. This information is often sent to a remote attacker, who can use it for identity theft, financial fraud, or unauthorized access to systems.
Types of Keyloggers
Software Keyloggers
These are malicious programs installed on a device, often through infected downloads, email attachments, or compromised websites. Once active, they run in the background, intercepting and recording keystrokes. Advanced software keyloggers can also capture screenshots, clipboard contents, and even audio or video from the device’s microphone or camera.
Hardware Keyloggers
These are physical devices connected between a keyboard and a computer, or embedded inside the keyboard itself. They record keystrokes directly from the hardware and store the data for later retrieval. Hardware keyloggers require physical access to the device to install and collect data, but they are generally harder to detect than software versions.
How Keyloggers Work
• Recording Keystrokes: Keyloggers monitor and log every key pressed on the keyboard.
• Data Storage/Transmission: The captured data is saved to a file, which may be accessed locally or sent remotely to an attacker.
• Additional Features: Some keyloggers can also capture screenshots, clipboard data, or even audio and video inputs
Detection and Protection
Detecting keyloggers can be challenging, especially for advanced variants that operate at the kernel level or are embedded in hardware. Specialized anti-keylogger software and regular security scans can help identify and remove software-based keyloggers. Physically inspecting hardware connections can help detect hardware-based keyloggers.