An improved technique to discover compromising electromagnetic emanations

Abstract

Abstract-The techniques generally used to detect compromising emanations are based on a wide-band receiver tuned on a specific frequency or a spectral analyzer with a limited bandwidth. However, these methods may not be optimal since a significant amount of information is lost during the signal acquisition. In this paper, we propose a straightforward but efficient approach which acquires raw signal directly from the antenna and processes the entire captured electromagnetic spectrum thanks to the computation of short time Fourier transforms. We applied this approach to detect potential compromising electromagnetic emanations radiated by modern keyboard. Since keyboards are often used to transmit confidential data such as passwords, these emanations could remotely reveal sensitive information such as keystrokes. Thanks to this method, we detected four different kinds of compromising electromagnetic emanations generated by wired and wireless keyboards. These emissions lead to a full or a partial recovery of the keystrokes. We implemented these side-channel attacks and our best practical attack fully recovered 95% of the keystrokes of a PS/2 keyboard at a distance up to 20 meters, even through walls.

A Threat for Tablet PCs in Public Space

“…At present, ICT devices at risk for EM information leakage include many commercial products, such as CRT and LCD monitors [2]- [12], printers [13], and keyboards [14] [15]. In particular, the threat of display capture via EM emanation, called EM display stealing, has been studied for the relatively larger displays of desktop and notebook PCs.…”

State‐of‐the‐art research on electromagnetic information security

“…Specifically, the following threats concerning leaks via electromagnetic radiation have been clearly identified: information on the screen of a desktop or notebook personal computer (PC) [Kuhn, 2011;Sekiguchi and Seto, 2011], information on the screen of a device such as a tablet or phone [Hayashi et al, 2014], information for business purposes calculated by the CPU of a PC [Zajic and Prvulovic, 2014], information output from a printer [Tosaka et al, 2006], keyboard input key information [Vuagnoux and Pasini, 2010], and secret key information in devices that process passwords [Agrawal et al, 2002].…”

Novel Method to Detect and Recover the Keystrokes of Ps/2 Keyboard

“…However, the processed confidential information by the ITEs also may be embedded within the EM disturbance, even if the radiation and conduction emission levels are less than the limits. The malicious adversaries can reconstruct the processed date by receiving and analyzing these EM noises [2][3][4][5][6][7][8][9][10][11]. In recent years, the information leakage caused by EM radiation and conduction is a hot topic in the field of computer security.…”