Passphrases Beat Thermal Attacks: Evaluating Text Input Characteristics Against Thermal Attacks on Laptops and Smartphones.

Abdrabou, Yasmeen and Hatem, Reem and Abdelrahman, Yomna and Mougy, Amr El and Khamis, Mohamed (2021) Passphrases Beat Thermal Attacks: Evaluating Text Input Characteristics Against Thermal Attacks on Laptops and Smartphones. In: Human-Computer Interaction – INTERACT 2021: 18th IFIP TC 13 International Conference, Bari, Italy, August 30 – September 3, 2021, Proceedings, Part IV :. Springer-Verlag, pp. 712-721. ISBN 9783030856090

Abstract

We investigate the effectiveness of thermal attacks against input of text with different characteristics; we study text entry on a smartphone touchscreen and a laptop keyboard. First, we ran a study (N = 25) to collect a dataset of thermal images of short words, websites, complex strings (special characters, numbers, letters), passphrases and words with duplicate characters. Afterwards, 20 different participants visually inspected the thermal images to attempt to identify the text input. We found that long and complex strings are less vulnerable to thermal attacks, that visual inspection of thermal images reveals different parts of the entered text (36% on average and up to 82%) even if the attack is not fully successful, and that entering text on laptops is more vulnerable to thermal attacks than on smartphones. We conclude with three learned lessons and recommendations to resist thermal attacks.