A keylogger is malicious software or hardware designed to capture and record every keystroke typed on a computer or mobile device without the user's knowledge. These covert surveillance tools represent one of the most persistent cybersecurity threats, capable of stealing passwords, credit card numbers, personal information, and confidential business data by monitoring keyboard input in real time.
Types of Keyloggers
Software Keyloggers
Application-Level Keyloggers: Monitor keyboard input within specific applications, targeting web browsers, email clients, and financial software where users enter sensitive credentials
Kernel-Level Keyloggers: Operate at the operating system core, providing comprehensive keystroke monitoring difficult to detect using standard security tools; require elevated privileges but monitor all keyboard activity
Hypervisor-Based Keyloggers: Operate at the virtualization layer, below the operating system, making them nearly impossible to detect from within the compromised system
Form Grabbers: Capture data submitted through web forms before it is encrypted for transmission
Hardware Keyloggers
USB Keyloggers: Physical devices connecting between keyboards and computers, capturing all input while appearing as legitimate USB devices to operating systems
Wireless Keyboard Sniffers: Intercept wireless signals between keyboards and receivers
Acoustic Keyloggers: Use sound analysis to identify keystrokes from keyboard sounds
How Keyloggers Operate: Keyloggers infiltrate systems through phishing emails, malicious downloads, infected USB drives, or physical hardware installation. Once active, they record typed characters, capture screenshots, monitor web activity, and track application usage patterns while operating silently in the background. Captured keystroke data is transmitted to remote servers controlled by attackers or stored locally for later retrieval.
Defense Against Keyloggers: Protection includes maintaining updated endpoint security software, using password managers (which auto-fill credentials without typing), implementing MFA, and training employees to avoid phishing emails that deliver keylogger payloads. Pangratis blocks phishing emails that deliver keylogger malware, preventing initial infection through the most common delivery vector.