What is a Keylogger ? - Security Term

Keylogger is a software program or hardware device that is used to monitor and log each of the keys a user types into a computer keyboard. The user who installed the program or hardware device can then view all keys typed in by that user. Because these programs and hardware devices monitor the keys typed in a user can easily find user passwords and other information a user may not wish others to know about.

Keyloggers, as a surveillance tool, are often used by employers to ensure employees use work computers for business purposes only. Unfortunately, keyloggers can also be embedded in spyware allowing your information to be transmitted to an unknown third party.

A keylogger is a program that runs in the background, recording all the keystrokes. Once keystrokes are logged, they are hidden in the machine for later retrieval, or shipped raw to the attacker. The attacker then peruses them carefully in the hopes of either finding passwords, or possibly other useful information that could be used to compromise the system or be used in a social engineering attack. For example, a keylogger will reveal the contents of all e-mail composed by the user. Keylogger is commonly included in rootkits.

A keylogger normally consists of two files: a DLL which does all the work and an EXE which loads the DLL and sets the hook. Therefore when you deploy the hooker on a system, two such files must be present in the same directory. There are other approaches to capturing info about what you are doing. Some keyloggers capture screens, rather than keystrokes. Other keyloggers will secretly turn on video or audio recorders, and transmit what they capture over your internet connection.

Because a keylogger can involve dozens of files, and has as a primary goal complete stealth from the user, removing one manually can be a terrifying challenge to any computer user. Incorrect removal efforts can result in damage to the operating system, instability, inability to use the mouse or keyboard, or worse. Further, some key loggers will survive manual efforts to remove them, re-installing themselves before the user even reboots.


source: freetechexams