Hardware keylogger
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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).
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[edit] 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.
[edit] Types of Hardware Keyloggers
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.
[edit] Countermeasures
Denial of physical access to sensitive computers, e.g. by locking the server room, is the most effective means of preventing hardware keylogger installation. Visual inspection is the primary means of detecting hardware keyloggers, since there are no known methods of detecting them through software. In cases in which the CPU is hidden from view (e.g. at some public access kiosks where the CPU is in a locked box and only a monitor, keyboard, and mouse are exposed to view), a user might thwart a keylogger by typing part of a password, using the mouse to move to a text editor or other window, typing some garbage text, mousing back to the password window, typing the next part of the password, etc. so that the keylogger will record an unintelligible mix of garbage and password text[1] See also Keystroke logging(Non-technological methods).
The main risk associated with keylogger use is that physical access is needed twice: initially to install the keylogger, and secondly to retrieve it. Thus, if the victim discovers the keylogger, they can then set up a sting operation to catch the person in the act of retrieving it. This could include camera surveillance or the review of access card swipe records to determine who gained physical access to the area during the time period that the keylogger was removed.
[edit] References
- ^ Hardware Keylogger Detection, SpyCop.
