CVSS 3.1
5.9 mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:NCVE-2020-24722
Medium (5.9) in exposure notifications project exposure notifications. EPSS 2.5% chance of exploitation in the next 30 days.
An issue was discovered in the GAEN (aka Google/Apple Exposure Notifications) protocol through 2020-10-05, as used in COVID-19 applications on Android and iOS. The encrypted metadata block with a TX value lacks a checksum, allowing bitflipping to amplify a contamination attack. This can cause metadata deanonymization and risk-score inflation. NOTE: the vendor's position is "We do not believe that TX power authentication would be a useful defense against relay attacks.
Severity
- EPSS
- 2.5% chance of exploitation in the next 30 days; higher than 84% of CVEs (scores of 2026-10-31)
- CWE
- CWE-294
- Published
- Modified
- Record from
- the NVD, synced
Affected
- exposure_notifications_project:exposure_notifications
References
- http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html
- http://seclists.org/fulldisclosure/2020/Oct/12
- https://blog.google/inside-google/company-announcements/update-exposure-notifications
- https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations
- http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html