CVE-2020-24722
2.6 Low
CVSS2
Attack Vector
NETWORK
Attack Complexity
HIGH
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:H/Au:N/C:N/I:P/A:N
5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
5.7 Medium
AI Score
Confidence
High
0.028 Low
EPSS
Percentile
90.7%
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
References
packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html
seclists.org/fulldisclosure/2020/Oct/12
blog.google/inside-google/company-announcements/update-exposure-notifications
github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations
Related
2.6 Low
CVSS2
Attack Vector
NETWORK
Attack Complexity
HIGH
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:H/Au:N/C:N/I:P/A:N
5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
5.7 Medium
AI Score
Confidence
High
0.028 Low
EPSS
Percentile
90.7%