What's in a name? Exploring CA certificate control

Zane Ma, Joshua Mason, Manos Antonakakis, Zakir Durumeric, Michael Bailey

Research output: Chapter in Book/Report/Conference proceedingConference contribution


TLS clients rely on a supporting PKI in which certificate authorities (CAs)-trusted organizations-validate and cryptographically attest to the identities of web servers. A client's confidence that it is connecting to the right server depends entirely on the set of CAs that it trusts. However, as we demonstrate in this work, the identity specified in CA certificates is frequently inaccurate due to lax naming requirements, ownership changes, and long-lived certificates. This not only muddles client selection of trusted CAs, but also prevents PKI operators and researchers from correctly attributing CA certificate issues to CA organizations. To help Web PKI participants understand the organizations that control each CA certificate, we develop Fides, a system that models and clusters CA operational behavior in order to detect CA certificates under shared operational control. We label the clusters that Fides uncovers, and build a new database of CA ownership that corrects the CA operator for 241 CA certificates, and expands coverage to 651 new CA certificates, leading to a more complete picture of CA certificate control.

Original languageEnglish (US)
Title of host publicationProceedings of the 30th USENIX Security Symposium
PublisherUSENIX Association
Number of pages18
ISBN (Electronic)9781939133243
StatePublished - 2021
Event30th USENIX Security Symposium, USENIX Security 2021 - Virtual, Online
Duration: Aug 11 2021Aug 13 2021

Publication series

NameProceedings of the 30th USENIX Security Symposium


Conference30th USENIX Security Symposium, USENIX Security 2021
CityVirtual, Online

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Information Systems
  • Safety, Risk, Reliability and Quality


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