CVE-2023-5528: Insufficient input sanitization in in-tree storage plugin leads to privilege escalation on Windows nodes

[cji]

CVSS Rating: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - HIGH (7.2)

A security issue was discovered in Kubernetes where a user that can create pods and persistent volumes on Windows nodes may be able to escalate to admin privileges on those nodes. Kubernetes clusters are only affected if they are using an in-tree storage plugin for Windows nodes.

Am I vulnerable?

Any kubernetes environment with Windows nodes is impacted. Run kubectl get nodes -l kubernetes.io/os=windows to see if any Windows nodes are in use.

Affected Versions

• kubelet >= v1.8.0 (including all later minor versions)

How do I mitigate this vulnerability?

The provided patch fully mitigates the vulnerability.

Outside of applying the provided patch, there are no known mitigations to this vulnerability.

Fixed Versions

• kubelet master - fixed by Use golang library instead of mklink #121881
• kubelet v1.28.4 - fixed by Automated cherry pick of #121881: Use golang library instead of mklink #121882
• kubelet v1.27.8 - fixed by Automated cherry pick of #121881: Use golang library instead of mklink #121883
• kubelet v1.26.11 - fixed by Automated cherry pick of #121881: Use golang library instead of mklink #121884
• kubelet v1.25.16 - fixed by Automated cherry pick of #121881: Use golang library instead of mklink #121885

To upgrade, refer to the documentation:
https://kubernetes.io/docs/tasks/administer-cluster/cluster-management/#upgrading-a-cluster

Detection

Kubernetes audit logs can be used to detect if this vulnerability is being exploited. Persistent Volume create events with local path fields containing special characters are a strong indication of exploitation.

If you find evidence that this vulnerability has been exploited, please contact security@kubernetes.io

Acknowledgements

This vulnerability was reported by Tomer Peled @tomerpeled92

The issue was fixed and coordinated by the fix team:

James Sturtevant @jsturtevant
Mark Rossetti @marosset
Michelle Au @msau42
Jan Šafránek @jsafrane
Mo Khan @enj
Rita Zhang @ritazh
Micah Hausler @micahhausler
Sri Saran Balaji @SaranBalaji90
Craig Ingram @cji

and release managers:
Jeremy Rickard @jeremyrickard
Marko Mudrinić @xmudrii

/area security
/kind bug
/committee security-response
/label official-cve-feed
/sig windows
/sig storage
/area kubelet

[cji]

kubelet v1.28.4, v1.27.8, v1.26.11, and v1.25.16 have all been released.