In the rapidly evolving field of cybersecurity, staying ahead of potential vulnerabilities is crucial. One such vulnerability that has surfaced is the exposed debug endpoint /debug/pprof in Kubernetes, identified as CVE-2019-11248. This blog post delves into the details of this vulnerability, its impact, and the necessary steps to remediate it.

Summary - Vulnerability Details

CVE-2019-11248 refers to the exposure of the debugging endpoint /debug/pprof over the unauthenticated Kubelet health port. This issue affects Kubernetes versions prior to 1.15.0, 1.14.4, 1.13.8, and 1.12.10. Although the severity of this vulnerability is considered medium, it does not pose a risk under the default configuration.

What is /debug/pprof?

The /debug/pprof endpoint is part of the Go language's profiling tool, pprof, which is used for the performance profiling of Go applications. It provides valuable insights into the application's runtime, such as goroutine stacks, heap allocations, and thread creation. However, when exposed publicly, it can be a security risk.

Affected Versions

• Kubernetes 1.14.3 and earlier
• Kubernetes 1.13.7 and earlier
• Kubernetes 1.12.9 and earlier

Endpoint Exposure

The /debug/pprof endpoint, if exposed, can leak sensitive information such as internal Kubelet memory addresses and configuration. Additionally, it may be exploited to cause a limited denial of service (DoS) by consuming excessive system resources through profiling endpoints like /debug/pprof/goroutine?debug=2.

‍Impact

The exposure of the /debug/pprof endpoint can have several repercussions:

1. Information Disclosure: Sensitive information such as internal memory addresses, application configuration, and runtime metrics can be accessed by unauthorized users.
2. Denial of Service: Attackers can exploit the profiling endpoints to perform resource-intensive operations, potentially leading to a denial of service.
3. Security Misconfiguration: The existence of such an exposed endpoint indicates a possible lack of proper security configurations and access controls.

Remediation

To mitigate this vulnerability, it is essential to ensure that access control rules are properly set for the /debug/* endpoints. Here are the steps to secure your Kubernetes environment:

1. Update Kubernetes: Upgrade to the latest stable version of Kubernetes, where this vulnerability is patched. Versions 1.15.0, 1.14.4, 1.13.8, and 1.12.10 and above have this issue resolved.
2. Configure Access Controls: Apply strict access control rules to restrict access to debugging endpoints. This can be done through network policies, firewalls, or API server authorization.
3. Monitor and Audit: Regularly monitor access logs and audit configurations to ensure that no unauthorized access to the /debug/* endpoints occur.

References

For more detailed information, you can refer to the following resources:

• NVD CVE-2019-11248
• CVE Details

Conclusion

CVE-2019-11248 highlights the importance of securing debugging and profiling endpoints in Kubernetes. By upgrading to the latest versions and implementing robust access controls, organizations can safeguard their environments from potential exploits. Stay vigilant and keep your systems updated to protect against such vulnerabilities.