research-article

Skype & Type: Keyboard Eavesdropping in Voice-over-IP

Authors:

Stefano Cecconello,

Alberto Compagno,

Gene TsudikAuthors Info & Claims

ACM Transactions on Privacy and Security (TOPS), Volume 22, Issue 4

Article No.: 24, Pages 1 - 34

https://doi.org/10.1145/3365366

Published: 06 December 2019 Publication History

Abstract

Voice-over-IP (VoIP) software are among the most widely spread and pervasive software, counting millions of monthly users. However, we argue that people ignore the drawbacks of transmitting information along with their voice, such as keystroke sounds—as such sound can reveal what someone is typing on a keyboard.

In this article, we present and assess a new keyboard acoustic eavesdropping attack that involves VoIP, called Skype & Type (S&T). Unlike previous attacks, S&T assumes a weak adversary model that is very practical in many real-world settings. Indeed, S&T is very feasible, as it does not require (i) the attacker to be physically close to the victim (either in person or with a recording device) and (ii) precise profiling of the victim’s typing style and keyboard; moreover, it can work with a very small amount of leaked keystrokes. We observe that leakage of keystrokes during a VoIP call is likely, as people often “multi-task” during such calls. As expected, VoIP software acquires and faithfully transmits all sounds, including emanations of pressed keystrokes, which can include passwords and other sensitive information. We show that one very popular VoIP software (Skype) conveys enough audio information to reconstruct the victim’s input—keystrokes typed on the remote keyboard. Our results demonstrate that, given some knowledge on the victim’s typing style and keyboard model, the attacker attains top-5 accuracy of 91.7% in guessing a random key pressed by the victim. This work extends previous results on S&T, demonstrating that our attack is effective with many different recording devices (such as laptop microphones, headset microphones, and smartphones located in proximity of the target keyboard), diverse typing styles and speed, and is particularly threatening when the victim is typing in a known language.

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Cited By

Shi ZLiu GWang NXiang T(2025)Keyboard acoustic-based multiple factor authenticationTenth Symposium on Novel Optoelectronic Detection Technology and Applications10.1117/12.3055978(82)Online publication date: 17-Feb-2025
https://doi.org/10.1117/12.3055978
Huang JBai JZhang XLiu ZFeng YLiu JSun XDong MLi M(2024)KeystrokeSniffer: An Off-the-Shelf Smartphone Can Eavesdrop on Your Privacy From AnywhereIEEE Transactions on Information Forensics and Security10.1109/TIFS.2024.342430119(6840-6855)Online publication date: 1-Jan-2024
https://dl.acm.org/doi/10.1109/TIFS.2024.3424301
Tanaka TRampazzi SSugawara T(2024)LightTouch: Harnessing Laser-Based Signal Injection to Manipulate Optical Human-Computer InterfacesIEEE Access10.1109/ACCESS.2024.341357112(84033-84045)Online publication date: 2024
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Index Terms

Skype & Type: Keyboard Eavesdropping in Voice-over-IP
1. Security and privacy
  1. Security in hardware
    1. Hardware attacks and countermeasures
      1. Side-channel analysis and countermeasures
  2. Security services
    1. Authentication

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Published In

cover image ACM Transactions on Privacy and Security

ACM Transactions on Privacy and Security Volume 22, Issue 4

November 2019

170 pages

ISSN:2471-2566

EISSN:2471-2574

DOI:10.1145/3364835

Editor:
David Basin
ETH Zurich, Switzerland

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Copyright © 2019 ACM.

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]

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Association for Computing Machinery

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Publication History

Published: 06 December 2019

Accepted: 01 September 2019

Revised: 01 April 2019

Received: 01 November 2018

Published in TOPS Volume 22, Issue 4

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Cited By

Shi ZLiu GWang NXiang T(2025)Keyboard acoustic-based multiple factor authenticationTenth Symposium on Novel Optoelectronic Detection Technology and Applications10.1117/12.3055978(82)Online publication date: 17-Feb-2025
https://doi.org/10.1117/12.3055978
Huang JBai JZhang XLiu ZFeng YLiu JSun XDong MLi M(2024)KeystrokeSniffer: An Off-the-Shelf Smartphone Can Eavesdrop on Your Privacy From AnywhereIEEE Transactions on Information Forensics and Security10.1109/TIFS.2024.342430119(6840-6855)Online publication date: 1-Jan-2024
https://dl.acm.org/doi/10.1109/TIFS.2024.3424301
Tanaka TRampazzi SSugawara T(2024)LightTouch: Harnessing Laser-Based Signal Injection to Manipulate Optical Human-Computer InterfacesIEEE Access10.1109/ACCESS.2024.341357112(84033-84045)Online publication date: 2024
https://doi.org/10.1109/ACCESS.2024.3413571
Taheritajar AHarris ZRahaeimehr R(2024)A Survey on Acoustic Side Channel Attacks on KeyboardsInformation and Communications Security10.1007/978-981-97-8798-2_6(99-121)Online publication date: 27-Aug-2024
https://dl.acm.org/doi/10.1007/978-981-97-8798-2_6
Ozkan AKilic BAcarturk C(2024)Keystroke Transcription from Acoustic Emanations Using Continuous Wavelet TransformMachine Learning for Cyber Security10.1007/978-981-97-2458-1_1(1-16)Online publication date: 23-Apr-2024
https://doi.org/10.1007/978-981-97-2458-1_1
Conti MDuroyon MOrazi GTsudik G(2024)Acoustic Side-Channel Attacks on a Computer MouseDetection of Intrusions and Malware, and Vulnerability Assessment10.1007/978-3-031-64171-8_3(44-63)Online publication date: 17-Jul-2024
https://dl.acm.org/doi/10.1007/978-3-031-64171-8_3
Long YYan CXiao SPrasad SXu WFu K(2023)Private Eye: On the Limits of Textual Screen Peeking via Eyeglass Reflections in Video Conferencing2023 IEEE Symposium on Security and Privacy (SP)10.1109/SP46215.2023.10179423(3432-3449)Online publication date: May-2023
https://doi.org/10.1109/SP46215.2023.10179423
Balagani KCardaioli MCecconello SConti MTsudik G(2022)We Can Hear Your PIN Drop: An Acoustic Side-Channel Attack on ATM PIN PadsComputer Security – ESORICS 202210.1007/978-3-031-17140-6_31(633-652)Online publication date: 26-Sep-2022
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Bai JLiu BSong LShen HZhuang YSmith JYang YCesar PMetze FPrabhakaran B(2021)I Know Your Keyboard InputProceedings of the 29th ACM International Conference on Multimedia10.1145/3474085.3475539(1239-1247)Online publication date: 17-Oct-2021
https://dl.acm.org/doi/10.1145/3474085.3475539
Lee KLee JChoi CYim K(2021)Offensive Security of Keyboard Data Using Machine Learning for Password Authentication in IoTIEEE Access10.1109/ACCESS.2021.30502399(10925-10939)Online publication date: 2021
https://doi.org/10.1109/ACCESS.2021.3050239
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