CVE-2023-41332: Denial of service via Kubernetes annotations in specific Cilium configurations
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.
Other sources
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. 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) or 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. This issue has been resolved in Cilium versions 1.14.2, 1.13.7, and 1.12.14. Users unable to upgrade can avoid this denial of service attack by enabling the Layer 7 proxy.
— MITRE
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the impact of CVE-2023-41332?
Creating workloads with specific annotations causes the Cilium agent to segfault on the affected node.
How is CVE-2023-41332 classified in terms of severity?
CVE-2023-41332 is classified as low severity with a CVSS score of 3.5.
What software versions are affected by CVE-2023-41332?
Versions 1.13.0 to 1.13.7, 1.12.14, and 1.14.0 to 1.14.2 of Cilium are affected by this vulnerability.
How can I fix CVE-2023-41332?
Upgrade Cilium to version 1.13.7 if using versions 1.13.0 to 1.13.6, or upgrade to version 1.12.14 if using version 1.12.0 to 1.12.13, or upgrade to version 1.14.2 if using versions 1.14.0 to 1.14.1.
Where can I find more information about CVE-2023-41332?
More information about CVE-2023-41332 can be found at the following references: [GitHub Advisory](https://github.com/cilium/cilium/security/advisories/GHSA-24m5-r6hv-ccgp), [GitHub Pull Request](https://github.com/cilium/cilium/pull/27597), [GitHub Security Advisory](https://github.com/advisories/GHSA-24m5-r6hv-ccgp).