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All the Numbers are US: Large-scale Abuse of Contact Discovery in Mobile Messengers

Hagen, Christoph ; Weinert, Christian ; Sendner, Christoph ; Dmitrienko, Alexandra ; Schneider, Thomas (2021)
All the Numbers are US: Large-scale Abuse of Contact Discovery in Mobile Messengers.
28. Annual Network and Distributed System Security Symposium (NDSS'21). virtual Conference (21.02.2021-24.02.2021)
doi: 10.14722/ndss.2021.23159
Konferenzveröffentlichung, Bibliographie

Kurzbeschreibung (Abstract)

Contact discovery allows users of mobile messengers to conveniently connect with people in their address book. In this work, we demonstrate that severe privacy issues exist in currently deployed contact discovery methods. Our study of three popular mobile messengers (WhatsApp, Signal, and Telegram) shows that, contrary to expectations, large-scale crawling attacks are (still) possible. Using an accurate database of mobile phone number prefixes and very few resources, we have queried 10% of US mobile phone numbers for WhatsApp and 100% for Signal. For Telegram we find that its API exposes a wide range of sensitive information, even about numbers not registered with the service. We present interesting (cross-messenger) usage statistics, which also reveal that very few users change the default privacy settings. Regarding mitigations, we propose novel techniques to significantly limit the feasibility of our crawling attacks, especially a new incremental contact discovery scheme that strictly improves over Signal's current approach. Furthermore, we show that currently deployed hashing-based contact discovery protocols are severely broken by comparing three methods for efficient hash reversal of mobile phone numbers. For this, we also propose a significantly improved rainbow table construction for non-uniformly distributed inputs that is of independent interest.

Typ des Eintrags: Konferenzveröffentlichung
Erschienen: 2021
Autor(en): Hagen, Christoph ; Weinert, Christian ; Sendner, Christoph ; Dmitrienko, Alexandra ; Schneider, Thomas
Art des Eintrags: Bibliographie
Titel: All the Numbers are US: Large-scale Abuse of Contact Discovery in Mobile Messengers
Sprache: Englisch
Publikationsjahr: 2021
Verlag: Internet Society
Veranstaltungstitel: 28. Annual Network and Distributed System Security Symposium (NDSS'21)
Veranstaltungsort: virtual Conference
Veranstaltungsdatum: 21.02.2021-24.02.2021
DOI: 10.14722/ndss.2021.23159
Kurzbeschreibung (Abstract):

Contact discovery allows users of mobile messengers to conveniently connect with people in their address book. In this work, we demonstrate that severe privacy issues exist in currently deployed contact discovery methods. Our study of three popular mobile messengers (WhatsApp, Signal, and Telegram) shows that, contrary to expectations, large-scale crawling attacks are (still) possible. Using an accurate database of mobile phone number prefixes and very few resources, we have queried 10% of US mobile phone numbers for WhatsApp and 100% for Signal. For Telegram we find that its API exposes a wide range of sensitive information, even about numbers not registered with the service. We present interesting (cross-messenger) usage statistics, which also reveal that very few users change the default privacy settings. Regarding mitigations, we propose novel techniques to significantly limit the feasibility of our crawling attacks, especially a new incremental contact discovery scheme that strictly improves over Signal's current approach. Furthermore, we show that currently deployed hashing-based contact discovery protocols are severely broken by comparing three methods for efficient hash reversal of mobile phone numbers. For this, we also propose a significantly improved rainbow table construction for non-uniformly distributed inputs that is of independent interest.

Freie Schlagworte: Engineering, E4
Fachbereich(e)/-gebiet(e): 20 Fachbereich Informatik
20 Fachbereich Informatik > Praktische Kryptographie und Privatheit
DFG-Sonderforschungsbereiche (inkl. Transregio)
DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche
DFG-Graduiertenkollegs
DFG-Graduiertenkollegs > Graduiertenkolleg 2050 Privacy and Trust for Mobile Users
Profilbereiche
Profilbereiche > Cybersicherheit (CYSEC)
LOEWE
LOEWE > LOEWE-Zentren
LOEWE > LOEWE-Zentren > CRISP - Center for Research in Security and Privacy
DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 1119: CROSSING – Kryptographiebasierte Sicherheitslösungen als Grundlage für Vertrauen in heutigen und zukünftigen IT-Systemen
Hinterlegungsdatum: 15 Sep 2020 11:08
Letzte Änderung: 20 Jun 2024 10:05
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