Hello Kubernetes Community,
A security issue was discovered in ingress-nginx where an actor with permission to create Ingress objects (in the networking.k8s.io or extensions API group) can bypass annotation validation to inject arbitrary commands and obtain the credentials of the ingress-nginx controller. In the default configuration, that credential has access to all secrets in the cluster.
This issue has been rated High (8.8) CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H and assigned CVE-2024-7646.
Am I vulnerable?
This bug affects ingress-nginx. If you do not have ingress-nginx installed on your cluster, you are not affected. You can check this by running kubectl get po -A and looking for ingress-nginx-controller.
Multi-tenant environments where non-admin users have permissions to create Ingress objects are most affected by this issue.
Affected Versions
ingress-nginx controller < v1.11.2
How do I mitigate this vulnerability?
This issue can be mitigated by upgrading to the fixed version.
Fixed Versions
ingress-nginx controller v1.11.2
Detection
Review your Kubernetes audit logs for Ingress objects created with annotations (e.g. nginx.ingress.kubernetes.io/auth-tls-verify-client) that contain carriage returns (\r).
If you find evidence that this vulnerability has been exploited, please contact security@kubernetes.io
Additional Details
See the GitHub issue for more details:
https://github.com/kubernetes/kubernetes/issues/126744
Acknowledgements
This vulnerability was reported by André Storfjord Kristiansen @dev-bio.
The issue was fixed and coordinated by the fix team:
André Storfjord Kristiansen @dev-bio
Jintao Zhang @tao12345666333
Marco Ebert @Gacko
Thank You,
Craig Ingram on behalf of the Kubernetes Security Response Committee