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Policy bypass for Host Firewall policy due to race condition in Cilium agent

Moderate severity GitHub Reviewed Published Aug 15, 2024 in cilium/cilium • Updated Aug 15, 2024

Package

gomod github.com/cilium/cilium (Go)

Affected versions

< 1.14.14
>= 1.15.0, < 1.15.8

Patched versions

1.14.14
1.15.8

Description

Impact

A race condition in the Cilium agent can cause the agent to ignore labels that should be applied to a node. This could in turn cause CiliumClusterwideNetworkPolicies intended for nodes with the ignored label to not apply, leading to policy bypass.

Patches

This issue was fixed in cilium/cilium#33511.

This issue affects:

  • All versions of Cilium before v1.14.14
  • Cilium v1.15 between v1.15.0 and v1.15.7 inclusive

This issue has been patched in:

  • Cilium v1.14.14
  • Cilium v1.15.8

Workarounds

As the underlying issue depends on a race condition, users unable to upgrade can restart the Cilium agent on affected nodes until the affected policies are confirmed to be working as expected.

Acknowledgements

The Cilium community has worked together with members of Google and Isovalent to prepare these mitigations. Special thanks to @skmatti for raising and resolving this issue.

For more information

If you have any questions or comments about this advisory, please reach out on Slack.

If you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at security@cilium.io. This is a private mailing list for the Cilium security team, and your report will be treated as top priority.

References

@ferozsalam ferozsalam published to cilium/cilium Aug 15, 2024
Published by the National Vulnerability Database Aug 15, 2024
Published to the GitHub Advisory Database Aug 15, 2024
Reviewed Aug 15, 2024
Last updated Aug 15, 2024

Severity

Moderate

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
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

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:H/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS score

0.064%
(30th percentile)

Weaknesses

CVE ID

CVE-2024-42488

GHSA ID

GHSA-q7w8-72mr-vpgw

Source code

Credits

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