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Specific Cilium configurations vulnerable to DoS via Kubernetes annotations

Low severity GitHub Reviewed Published Sep 26, 2023 in cilium/cilium • Updated Nov 9, 2023

Package

gomod github.com/cilium/cilium (Go)

Affected versions

>= 1.14.0, < 1.14.2
< 1.12.14
>= 1.13.0, < 1.13.7

Patched versions

1.14.2
1.12.14
1.13.7

Description

Impact

In Cilium clusters where Cilium's Layer 7 proxy has been disabled, creating workloads with

  • policy.cilium.io/proxy-visibility annotations (in Cilium >= v1.13)
  • io.cilium.proxy-visibility annotations (in Cilium <= v1.12)

causes the Cilium agent to segfault on the node to which the workload is assigned.

Existing traffic on the affected node will continue to flow, but the Cilium agent on the node will not able to process changes to workloads running on the node. This will also prevent workloads from being able to start on the affected node. The denial of service will be limited to the node on which the workload is scheduled, however an attacker may be able to schedule workloads on the node of their choosing, which could lead to targeted attacks.

Patches

Pull request with fix

This issue affects:

Cilium <= v1.14.1
Cilium <= v1.13.6
Cilium <= v1.12.13

This issue has been resolved in:

Cilium v1.14.2
Cilium v1.13.7
Cilium v1.12.14

Workarounds

Users can avoid this denial of service attack by enabling the Layer 7 proxy.

For more information

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

As usual, if you think you found a related vulnerability, we strongly encourage you to report security vulnerabilities to our private security mailing list: security@cilium.io - first, before disclosing them in any public forums. This is a private mailing list where only members of the Cilium internal security team are subscribed to, and is treated as top priority.

References

@ferozsalam ferozsalam published to cilium/cilium Sep 26, 2023
Published to the GitHub Advisory Database Sep 27, 2023
Reviewed Sep 27, 2023
Published by the National Vulnerability Database Sep 27, 2023
Last updated Nov 9, 2023

Severity

Low

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
Adjacent
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

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:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

EPSS score

0.043%
(10th percentile)

Weaknesses

CVE ID

CVE-2023-41332

GHSA ID

GHSA-24m5-r6hv-ccgp

Source code

Credits

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