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O2 VoLTE: locating any customer with a phone call

a year ago
  • #VoLTE
  • #Privacy
  • #Security
  • VoLTE uses IP Multimedia Subsystem (IMS) for internet-based calls on mobile networks.
  • IMS complexity has led to device incompatibility and security concerns.
  • O2 UK's IMS implementation, '4G Calling', launched in 2017, exposes sensitive data in SIP messages.
  • Headers in SIP messages reveal IMSIs, IMEIs, and Cell IDs of callers and recipients.
  • Cell ID data can be used to geolocate users with high accuracy, even when roaming.
  • O2 lacks a clear escalation route for reporting security vulnerabilities.
  • No response from O2 after attempts to report the privacy risk in March 2025.