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Failure to delete orphaned role bindings do not revoke project level access from group based authentication

High
cbron published GHSA-28g7-896h-695v Apr 1, 2022

Package

Rancher (Rancher)

Affected versions

Up to and including 2.4.17, 2.5.11 and 2.6.2

Patched versions

2.4.18, 2.5.12, 2.6.3 and later releases

Description

Impact

This vulnerability only affects customers using group based authentication in Rancher versions up to and including 2.4.17, 2.5.11 and 2.6.2.

When removing a Project Role associated to a group from a project, the bindings that grant access to cluster scoped resources for those subjects do not get deleted. This happens due to an incomplete authorization logic check. A user who is a member of an affected group with authenticated access to Rancher could use this to access resources they should no longer have access to. The exposure level will depend on the original permission level granted to the affected project role.

Patches

Patched versions include releases 2.4.18, 2.5.12, 2.6.3 and later versions.

Workarounds

Limit access in Rancher to trusted users. There is not a direct mitigation besides upgrading to the patched Rancher versions.

References

Cluster and project roles documentation for Rancher 2.6, 2.5 and 2.4.

For more information

If you have any questions or comments about this advisory:

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
Required
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:R/S:U/C:H/I:H/A:H

CVE ID

CVE-2021-36775

Weaknesses