CVEvulnerability
CVE-2020-24722
5.9 MEDIUM
Official page ↗
- Status
- Modified
- Published
- 2020-10-07
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- CVSS 2.0 ([email protected])
- 2.6 LOW — AV:N/AC:H/Au:N/C:N/I:P/A:N
- Weaknesses
- CWE-294
Description
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.
Affected configurations
• exposure notifications project exposure notifications (<= 2020-10-05)
Related
Weakness · CWE (1)
- CWE-294 Authentication Bypass by Capture-replay weakness
References
- http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html Exploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2020/Oct/12 Exploit, Mailing List, Third Party Advisory
- https://blog.google/inside-google/company-announcements/update-exposure-notifications Third Party Advisory
- https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations Third Party Advisory
- http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html Exploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2020/Oct/12 Exploit, Mailing List, Third Party Advisory
- https://blog.google/inside-google/company-announcements/update-exposure-notifications Third Party Advisory
- https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations Third Party Advisory