8.5
HIGH
CVE-2021-32783
Contour ExternalName Service Denial of Service and Secret Exposure
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.

INFO

Published Date :

July 23, 2021, 10:15 p.m.

Last Modified :

Aug. 5, 2021, 4:56 p.m.

Remotely Exploitable :

Yes !

Impact Score :

4.7

Exploitability Score :

3.1
Affected Products

The following products are affected by CVE-2021-32783 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Projectcontour contour
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-32783.

URL Resource
https://github.com/projectcontour/contour/commit/b53a5c4fd927f4ea2c6cf02f1359d8e28bef852e Patch Third Party Advisory
https://github.com/projectcontour/contour/releases/tag/v1.17.1 Release Notes Third Party Advisory
https://github.com/projectcontour/contour/security/advisories/GHSA-5ph6-qq5x-7jwc Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-32783 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-32783 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Initial Analysis by [email protected]

    Aug. 05, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:S/C:P/I:N/A:P)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
    Changed Reference Type https://github.com/projectcontour/contour/commit/b53a5c4fd927f4ea2c6cf02f1359d8e28bef852e No Types Assigned https://github.com/projectcontour/contour/commit/b53a5c4fd927f4ea2c6cf02f1359d8e28bef852e Patch, Third Party Advisory
    Changed Reference Type https://github.com/projectcontour/contour/releases/tag/v1.17.1 No Types Assigned https://github.com/projectcontour/contour/releases/tag/v1.17.1 Release Notes, Third Party Advisory
    Changed Reference Type https://github.com/projectcontour/contour/security/advisories/GHSA-5ph6-qq5x-7jwc No Types Assigned https://github.com/projectcontour/contour/security/advisories/GHSA-5ph6-qq5x-7jwc Third Party Advisory
    Added CWE NIST CWE-610
    Added CPE Configuration OR *cpe:2.3:a:projectcontour:contour:*:*:*:*:*:kubernetes:*:* versions up to (excluding) 1.17.1
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-32783 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-32783 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.10 }} 0.00%

score

0.38886

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability