A keylogger is a spying tool used to obtain private information from a computer user.
Keyloggers have different functionalities depending upon their type, but basically, there are two types of keyloggers:
• Keylogger software
• Hardware-based keyloggers
After installation, the software keylogger saves all the information entered by the user to the computer using a keyboard to a log file.
Keyloggers can then present this information to the attacker. Sophisticated keyloggers can send this information to a remote server, or even they can email that information to another person.
Keyloggers can store mouse gestures, web browsing history, and cookies and can take snapshots of your screen. Keyloggers can also save a communication like chatting taking place between two users.
These keyloggers work in stealth mode, making them difficult to detect. To display the log file of a keylogger, you can use a specific key sequence to activate the keylogger.
The hardware-based keylogger works in the same way; the only difference is that it comes as a device attached between the PS/2 or USB port and the keyboard.
The hardware-based keylogger is more efficient, and it does not require any installation, making it even more challenging to detect or remove.