[kubernetes] CVE-2024-3744: azure-file-csi-driver discloses service account tokens in logs

[Rita Zhang <rita.z.zhang () gmail com>]

Hello Kubernetes Community,

A security issue was discovered in azure-file-csi-driver where an actor
with access to the driver logs could observe service account tokens. These
tokens could then potentially be exchanged with external cloud providers to
access cloud resources.  Tokens are only logged when TokenRequests is
configured in the CSIDriver object
<https://kubernetes-csi.github.io/docs/token-requests.html> and the driver
is set to run at log level 2 or greater via the -v flag.

This issue has been rated **MEDIUM**
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
<https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N>
(6.5), and assigned **CVE-2024-3744**

*Am I vulnerable?*

You may be vulnerable if TokenRequests is configured in the CSIDriver object
<https://kubernetes-csi.github.io/docs/token-requests.html> and the driver
is set to run at log level 2 or greater via the -v flag and you are using
workload identity federation.

To check if token requests are configured, run the following command:

kubectl get csidriver file.csi.azure.com -o jsonpath="{.spec.tokenRequests}"

To check if tokens are being logged, examine the secrets-store container
log:

kubectl logs csi-azurefile-controller-56bfddd689-dh5tk -c azurefile -f |
grep --line-buffered "csi.storage.k8s.io/serviceAccount.tokens"

*Affected Versions*

- azure-file-csi-driver <= v1.29.3

- azure-file-csi-driver v1.30.0

*How do I mitigate this vulnerability?*

Prior to upgrading, this vulnerability can be mitigated by running
azure-file-csi-driver at log level 0 or 1 via the -v flag.

*Fixed Versions*

- azure-file-csi-driver v1.29.4

- azure-file-csi-driver v1.30.1

To upgrade, refer to the documentation:
https://github.com/kubernetes-sigs/azurefile-csi-driver?tab=readme-ov-file#install-driver-on-a-kubernetes-cluster


*Detection*

Examine cloud provider logs for unexpected token exchanges, as well as
unexpected access to cloud resources.

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

*Acknowledgements*

This vulnerability was patched by Weizhi Chen @cvvz from Microsoft.

Thank You,

Rita Zhang on behalf of the Kubernetes Security Response Committee