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Privilege escalation in rbac

High severity GitHub Reviewed Published Mar 15, 2021 in google/exposure-notifications-verification-server • Updated Feb 1, 2023

Package

gomod github.com/google/exposure-notifications-verification-server (Go)

Affected versions

< 0.23.0

Patched versions

0.23.1

Description

Impact

Using a carefully crafted request or malicious proxy, a user with UserWrite permissions could create another user with higher privileges than their own due to insufficient checks on the allowed set of permissions. The event would be captured in the Event Log.

Patches

The issue has been fixed in 0.24.0 and 0.23.1.

Workarounds

For users who are unable to upgrade, we recommend auditing users who have UserWrite permissions and regularly reviewing the Event Log for malicious activity.

Kudos

Thank you to Michael Mazzolini (Ethical Hacker at WHO) for finding and disclosing this vulnerability.

References

@sethvargo sethvargo published to google/exposure-notifications-verification-server Mar 15, 2021
Published by the National Vulnerability Database Mar 31, 2021
Reviewed May 20, 2021
Published to the GitHub Advisory Database May 21, 2021
Last updated Feb 1, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.127%
(48th percentile)

Weaknesses

CVE ID

CVE-2021-22538

GHSA ID

GHSA-5v95-v8c8-3rh6

Source code

No known source code
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