A keylogger is a type of surveillance technology used to monitor and record each keystroke typed on a specific computer's keyboard that is often used as a spyware tool by cybercriminals to steal personally identifiable information, login credentials and gain access to sensitive enterprise data.
There are two types of keyloggers; hardware and software.
A hardware-based keylogger is a small device that serves as a connector between the keyboard and the computer. The device is designed to resemble an ordinary part of the computer cabling or a USB adaptor, making it relatively easy for someone who wants to steal keystrokes to do so undetected. However, hardware keyloggers require the criminal to have physical access to the computer and are therefore rare in comparison to software based keyloggers.
A keylogging software program does not require physical access to the user's computer for installation. It is usually malware downloaded unwittingly by clicking on a link in a phishing email or website and can launch and operate stealthily in order to evade manual detection or antivirus scans. Keylogger software can infect all types of devices including PC and Apple desktops and laptops as well as smartphones, such as the Apple iPhone and all Android devices.