What is the CVSS score of CVE-2021-32783?

CVE-2021-32783 has a CVSS 3.1 base score of 8.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H. EPSS exploitation probability: 1.2%.

Is there a patch available for CVE-2021-32783?

Yes, a patch is available for CVE-2021-32783. Update the affected software to the latest version immediately.

Kubernetes CVE-2021-32783

HIGH

Unintended Proxy or Intermediary ('Confused Deputy') (CWE-441)

2021-07-23 security-advisories@github.com

Kubernetes Denial Of Service Contour

8.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.5 HIGH

AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

None

Availability

High

Lifecycle Timeline

CVE Published

Jul 23, 2021 - 22:15 nvd

HIGH 8.5

DescriptionNVD

Contour is a Kubernetes ingress controller using Envoy proxy. In Contour before version 1.17.1 a specially crafted ExternalName type Service may be used to access Envoy's admin interface, which Contour normally prevents from access outside the Envoy container. This can be used to shut down Envoy remotely (a denial of service), or to expose the existence of any Secret that Envoy is using for its configuration, including most notably TLS Keypairs. However, it *cannot* be used to get the *content* of those secrets. Since this attack allows access to the administration interface, a variety of administration options are available, such as shutting down the Envoy or draining traffic. In general, the Envoy admin interface cannot easily be used for making changes to the cluster, in-flight requests, or backend services, but it could be used to shut down or drain Envoy, change traffic routing, or to retrieve secret metadata, as mentioned above. The issue will be addressed in Contour v1.18.0 and a cherry-picked patch release, v1.17.1, has been released to cover users who cannot upgrade at this time. For more details refer to the linked GitHub Security Advisory.

AnalysisAI

Contour is a Kubernetes ingress controller using Envoy proxy. Rated high severity (CVSS 8.5), this vulnerability is remotely exploitable, low attack complexity.

Technical ContextAI

This vulnerability is classified under CWE-441. Contour is a Kubernetes ingress controller using Envoy proxy. In Contour before version 1.17.1 a specially crafted ExternalName type Service may be used to access Envoy's admin interface, which Contour normally prevents from access outside the Envoy container. This can be used to shut down Envoy remotely (a denial of service), or to expose the existence of any Secret that Envoy is using for its configuration, including most notably TLS Keypairs. However, it *cannot* be used to get the *content* of those secrets. Since this attack allows access to the administration interface, a variety of administration options are available, such as shutting down the Envoy or draining traffic. In general, the Envoy admin interface cannot easily be used for making changes to the cluster, in-flight requests, or backend services, but it could be used to shut down or drain Envoy, change traffic routing, or to retrieve secret metadata, as mentioned above. The issue will be addressed in Contour v1.18.0 and a cherry-picked patch release, v1.17.1, has been released to cover users who cannot upgrade at this time. For more details refer to the linked GitHub Security Advisory. Affected products include: Projectcontour Contour. Version information: version 1.17.1.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.