Vulnerability · Published Oct 7, 2020 · Assigned by mitre

CVE-2020-24722

Medium 5.9

In plain English

A medium-severity security flaw in the affected software. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.5% (higher than 85% of all known vulnerabilities).

Severity (CVSS NVD)5.9Medium

Exploit odds (30 days)2.5%top 15.5% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official 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 products (as reported)

Vendor	Product	Versions
n/a	n/a	n/a

References

https://blog.google/inside-google/company-announcements/update-exposure-notifications x_refsource_MISC
http://seclists.org/fulldisclosure/2020/Oct/12 x_refsource_MISC
https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations x_refsource_MISC
http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html x_refsource_MISC