Hardware Keylogger

Hardware Keyloggers are used for keystroke logging, a method of capturing and recording computer user keystrokes. They plug in between a computer keyboard and a computer and log all keyboard activity to an internal memory. They are typically designed to have an innocuous appearance that blends in with the rest of the hardware, such as appearing to be an EMC Balun.

They are designed to work with PS/2 keyboards, and more recently with USB keyboards.

Hardware keyloggers have an advantage over software keyloggers as they begin logging from the moment a computer is turned on (and are therefore able to collect a BIOS password for instance), and do not require software installation (unlike software solutions).

How do they work?

All hardware keyloggers have to have the following:

• A microcontroller - this interprets the datastream between the keyboard and computer, processes it, and passes it to the non-volatile memory
• A non-volatile memory device, such as Flash - this stores the recorded data, retaining it even when power is lost

Generally, recorded data is retrieved by typing a special password into a computer text editor. The hardware keylogger plugged in between the keyboard and computer detects that the password has been typed and then presents the computer with "typed" data to produce a menu. Beyond text menu some keyloggers offer a high-speed download to speed up retrieval of stored data; this can be via USB mass-storage enumeration or with a USB or serial download adapter.

Types of Hardware Keyloggers

All hardware keyloggers have to have the following:

1. Regular Hardware Keyloggers - are used for keystroke logging by means of a hardware circuit that is attached somewhere in between the computer keyboard and the computer. It logs all keyboard activity to its internal memory which can be accessed by typing in a series of pre-defined characters. A hardware keylogger has an advantage over a software solution; because it is not dependent on the computers operating system it will not interfere with any program running on the target machine and hence cannot be detected by any software.



2. Remote Access Hardware Keyloggers – Or otherwise know as Wireless Hardware Keyloggers work in much the same way as regular hardware keyloggers. Except they have the ability to be controlled and monitored remotely by means of a wireless communication standard.



3. Wireless Keylogger sniffers - Collect packets of data being transferred from a wireless keyboard and its receiver and then attempts to crack the encryption key being used to secure wireless communications between the two devices.