CVE-2021-32783

Published Jul 23, 2021

Last updated 3 years ago

CVSS high 8.5

Overview

Description: 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.
Source: security-advisories@github.com
NVD status: Analyzed

Risk scores

CVSS 3.1

Type: Primary
Base score: 8.5
Impact score: 4.7
Exploitability score: 3.1
Vector string: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
Severity: HIGH

CVSS 2.0

Type: Primary
Base score: 5.5
Impact score: 4.9
Exploitability score: 8
Vector string: AV:N/AC:L/Au:S/C:P/I:N/A:P

Weaknesses

nvd@nist.gov: CWE-610
security-advisories@github.com: CWE-441

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "negate": false,
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:projectcontour:contour:*:*:*:*:*:kubernetes:*:*",
            "vulnerable": true,
            "matchCriteriaId": "C1D1AE1D-573C-4C57-8117-914E6FB9C7AF",
            "versionEndExcluding": "1.17.1"
          }
        ],
        "operator": "OR"
      }
    ]
  }
]

Overview

Risk scores

CVSS 3.1

CVSS 2.0

Weaknesses

Social media

Configurations

References