Hardware-based keyloggers A hardware-based keylogger. A connected hardware-based keylogger. Main article: Hardware keylogger Hardware-based keyloggers do not depend upon any software being installed as they exist at a hardware level in a computer system. *.Firmware-based: BIOS-level firmwarethat handles keyboard events can be modified to record these events as they are processed. Physical and/or root-level accessis required to the machine, and the software loaded into the BIOS needs to be created for the specific hardware that it will be running on. [ 13 ] *.Keyboard hardware: Hardware keyloggers are used for keystroke logging by means of a hardware circuit that is attached somewhere in between the computer keyboardand the computer, typically inline with the keyboards cable connector. There are also USBconnectors based Hardware keyloggers as well as ones for Laptop computers. the Mini-PCI card plugs into the expansion slot of a laptop. More stealthy implementations can be installed or built into standard keyboards, so that no device is visible on the external cable. Both types log all keyboard activity to their internal memory, which can be subsequently accessed, for example, by typing in a secret key sequence. [ 14 ]A hardware keylogger has an advantage over a software solution: it is not dependent on being installed on the target computers operating system and therefore will not interfere with any program running on the target machine or be detected by any software. However its physical presence may be detected if, for example, it is installed outside the case as an inline device between the computer and the keyboard. Some of these implementations have the ability to be controlled and monitored remotely by means of a wireless communication standard. [ 15 ] *.Wireless keyboard sniffers: These passive sniffers collect packets of data being transferred from a wireless keyboard and its receiver. As encryption may be used to secure the wireless communications between the two devices, this may need to be cracked beforehand if the transmissions are to be read. *.Keyboard overlays: Criminals have been known to use keyboard overlays on ATMsto capture peoples PINs. Each keypress is registered by the keyboard of the ATM as well as the criminals keypad that is placed over it. The device is designed to look like an integrated part of the machine so that bank customers are unaware of its presence. [ 16 ] *.Acoustic keyloggers: Acoustic cryptanalysiscan be used to monitor the sound created by someone typing on a computer. Each key on the keyboard makes a subtly different acoustic signature when struck. It is then possible to identify which keystroke signature relates to which keyboard character via statistical methodssuch as frequency analysis. The repetition frequency of similar acoustic keystroke signatures, the timings between different keyboard strokes and other context information such as the probable language in which the user is writing are used in this analysis to map sounds to letters. [ 17 ]A fairly long recording (1000 or more keystrokes) is required so that a big enough sampleis collected. [ 18 ] *.Electromagnetic emissions: It is possible to capture the electromagnetic emissionsof a wired keyboard from up to 20 metres (66 ft) away, without being physically wired to it. [ 19 ]In 2009, Swiss researchers tested 11 different USB, PS/2and laptop keyboards in a semi- anechoic chamberand found them all vulnerable, primarily because of the prohibitive cost of adding shieldingduring manufacture. [ 20 ]The researchers used a wide-band receiverto tune into the specific frequency of the emissions radiated from the keyboards.
Posted on: Sun, 24 Aug 2014 16:21:19 +0000
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