keylogger

A keylogger is a surveillance tool designed to record a user’s keystrokes. It can be implemented as hardware placed between the keyboard and computer or as a software program that runs on the device. Some keyloggers also capture additional data such as application activity, clipboard contents, screenshots, or form data submitted in web pages.

Hardware keyloggers are physical devices that intercept electrical signals or USB communications. Software keyloggers operate at the operating system level, embedding themselves in the system as background processes or services. Modern variants may attempt to operate covertly, reporting logs to a local file or transmitting them to a remote server.

Keyloggers have legitimate uses, such as parental control, employee monitoring with proper consent, or digital forensics. They can also be used maliciously to steal passwords and other sensitive information, raise privacy concerns, or bypass security controls. Legal restrictions vary by jurisdiction and context, and improper installation can be illegal and violate privacy rights.

Detecting and preventing keyloggers involves endpoint protection, regular system auditing, and physical security for hardware devices. Users should employ up-to-date security software, enable two-factor authentication, use password managers, avoid using untrusted devices, and apply software updates. In organizations, clear monitoring policies and user consent are important components of lawful use.

Related topics include spyware, digital forensics, and monitoring software.