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 vendors position is We do not believe that TX power authentication would be a useful defense against relay attacks.
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Exposure_notifications | Exposure_notifications_project | * | 2020-10-05 (including) |