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Security Advisories: GSA_kwCzR0hTQS01d2o0LXdmZnEtMzM3OM4AA2tO

Ingress nginx annotation injection causes arbitrary command execution

Issue Details

A security issue was identified in ingress-nginx where the nginx.ingress.kubernetes.io/configuration-snippet annotation on an Ingress object (in the networking.k8s.io or extensions API group) can be used 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 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L), and assigned CVE-2023-5043.

Affected Components and Configurations

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 -n ingress-nginx.

If you are running the “chrooted” ingress-nginx controller introduced in v1.2.0 (gcr.io/k8s-staging-ingress-nginx/controller-chroot), command execution is possible but credential extraction is not, so the High severity does not apply.

Multi-tenant environments where non-admin users have permissions to create Ingress objects are most affected by this issue.

Affected Versions

<v1.9.0

Versions allowing mitigation

v1.9.0

Mitigation

Ingress Administrators should set the --enable-annotation-validation flag to enforce restrictions on the contents of ingress-nginx annotation fields.

Detection

If you find evidence that this vulnerability has been exploited, please contact [email protected]

Additional Details

See ingress-nginx Issue #10571 for more details.

Acknowledgements

This vulnerability was reported by suanve

Thank You,
CJ Cullen on behalf of the Kubernetes Security Response Committee

Permalink: https://github.com/advisories/GHSA-5wj4-wffq-3378
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS01d2o0LXdmZnEtMzM3OM4AA2tO
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: about 1 year ago
Updated: about 1 year ago

CVSS Score: 7.6
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L

EPSS Percentage: 0.00262
EPSS Percentile: 0.66351

Identifiers: GHSA-5wj4-wffq-3378, CVE-2023-5043
References:

• https://nvd.nist.gov/vuln/detail/CVE-2023-5043
• https://github.com/kubernetes/ingress-nginx/issues/10571
• https://groups.google.com/g/kubernetes-security-announce/c/pVsXsOpxYZo
• http://www.openwall.com/lists/oss-security/2023/10/25/4
• https://github.com/advisories/GHSA-5wj4-wffq-3378

Repository: https://github.com/kubernetes/ingress-nginx
Blast Radius: 0.0

Affected Packages