Skip to content

Insecure entropy in Argo CD's PKCE/Oauth2/OIDC params

High severity GitHub Reviewed Published Jun 21, 2022 in argoproj/argo-cd • Updated Jul 21, 2023

Package

gomod github.com/argoproj/argo-cd (Go)

Affected versions

>= 0.11.0, <= 1.8.7

Patched versions

2.1.16
gomod github.com/argoproj/argo-cd/v2 (Go)
< 2.1.16
>= 2.2.0, < 2.2.10
>= 2.3.0, < 2.3.5
= 2.4.0
2.1.16
2.2.10
2.3.5
2.4.1

Description

Impact

All versions of Argo CD starting with v0.11.0 are vulnerable to a variety of attacks when an SSO login is initiated from the Argo CD CLI or UI. The vulnerabilities are due to the use of insufficiently random values in parameters in Oauth2/OIDC login flows. In each case, using a relatively-predictable (time-based) seed in a non-cryptographically-secure pseudo-random number generator made the parameter less random than required by the relevant spec or by general best practices. In some cases, using too short a value made the entropy even less sufficient. (The specific weak parameters are listed in the References section.)

The attacks on login flows which are meant to be mitigated by these parameters are difficult to accomplish but can have a high impact (potentially granting an attacker admin access to Argo CD). The CVSS for this Security Advisory assumes the worst-case scenario.

Patches

A patch for this vulnerability has been released in the following Argo CD versions:

  • v2.4.1
  • v2.3.5
  • v2.2.10
  • v2.1.16

Workarounds

There are no workarounds. You must upgrade to a patched version to resolve the vulnerability.

References

These are the insufficiently-random parameters:

  1. (since 0.11.0) The state parameter generated by the argocd login command for Oauth2 login used a non-cryptographically secure source of entropy and generated a parameter that was too short to provide the entropy required in the spec. This parameter is a "recommended" part of the Oauth2 flow and helps protect against cross-site request forgery attacks.
  2. (since 1.7.2, when PKCE was added) The code_verifier parameter generated by the argocd login command for Oauth2+PKCE login used a non-cryptographically secure source of entropy. The attacks mitigated by PKCE are complex but have been observed in the wild.
  3. (since 0.11.0) The state parameter generated by the Argo CD API server during a UI-initiated Oauth2 login used a non-cryptographically secure source of entropy and generated a parameter that was too short to provide the entropy required in the spec. This parameter is a "recommended" part of the Oauth2 flow and helps protect against cross-site request forgery attacks.
  4. (since 0.11.0) The nonce parameter generated by the Argo CD API server during a UI-initiated Oauth2 implicit flow login used a non-cryptographically secure source of entropy and generated a parameter that was too short to provide sufficient entropy. This parameter is a required part of the OIDC implicit login flow and helps protect against replay attacks.

Credits

Originally discovered by @jgwest. @jannfis and @crenshaw-dev re-discovered the vulnerability when reviewing notes from ADA Logics' security audit of the Argo project sponsored by CNCF and facilitated by OSTIF. Thanks to Adam Korczynski and David Korczynski for their work on the audit.

For more information

References

@crenshaw-dev crenshaw-dev published to argoproj/argo-cd Jun 21, 2022
Published to the GitHub Advisory Database Jun 21, 2022
Reviewed Jun 21, 2022
Published by the National Vulnerability Database Jun 27, 2022
Last updated Jul 21, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS score

0.349%
(72nd percentile)

CVE ID

CVE-2022-31034

GHSA ID

GHSA-2m7h-86qq-fp4v

Source code

Credits

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.