QID 376091

Date Published: 2021-11-30

QID 376091: Kubernetes Webhook Redirect in kube-apiserver Vulnerability

Kubernetes is an open-source container-orchestration system for automating deployment, scaling and management of containerized applications.
Affected version:
all known versions of kube-apiserver.

QID Detection Logic:(Authenticated)
The QID uses 'kubectl version' command to check for vulnerable versions of Kubernetes and also checks if 'kube-apiserver' is running or not.

Successful exploitation of the vulnerability may allow an attacker to validate webhook Configuration requests are able to redirect kube-apiserver requests to private networks of the apiserver

  • CVSS V3 rated as Medium - 4.1 severity.
  • CVSS V2 rated as Medium - 4 severity.
    • Solution
    As patched version is not available, customers are advised to apply mitigation. For more information please visit here

    Workaround:
    This issue can be mitigated by not allowing kube-apiserver access to sensitive resources or networks, or to reduce the "-v" flag value to less than 10 and set the "--profiling" flag value to "false" (default value is "true"). Setting the profiling flag to "false" prevents users from dynamically modifying the kube-apiserver log level, and the flag value Webhook requests may still be redirected to private networks with a log level less than 10, but the response body will not be logged.

    Vendor References

    CVEs related to QID 376091

    CVE-2020-8561 |
    Software Advisories
    Advisory ID Software Component Link
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