CVE-2024-31989: Argo CD Privilege Escalation Vulnerability

CVE-2024-31989 Overview

CVE-2024-31989 is a critical privilege escalation vulnerability discovered in Argo CD, a declarative GitOps continuous delivery tool for Kubernetes. The vulnerability allows an unprivileged pod in a different namespace on the same cluster to connect to the Redis server on port 6379. This security flaw stems from the fact that even with the latest version of the VPC CNI plugin installed on EKS clusters, network policies require manual enablement through configuration to enforce access controls. This misconfiguration issue raises significant concerns that many organizations may unknowingly have open access to their Redis servers, potentially leading to privilege escalation to the level of cluster controller or sensitive information leakage.

Critical Impact

Successful exploitation enables attackers to escalate privileges to cluster controller level or leak sensitive information from the Argo CD deployment, compromising the entire GitOps pipeline and potentially affecting all managed Kubernetes workloads.

Affected Products

• Argoproj Argo CD versions prior to 2.8.19
• Argoproj Argo CD versions prior to 2.9.15
• Argoproj Argo CD versions prior to 2.10.10

Discovery Timeline

• May 21, 2024 - CVE-2024-31989 published to NVD
• January 9, 2025 - Last updated in NVD database

Technical Details for CVE-2024-31989

Vulnerability Analysis

This vulnerability exploits the default network configuration in Kubernetes environments where Argo CD is deployed. The Redis server used by Argo CD for caching and session management is exposed on port 6379 without proper network segmentation. In cloud environments like Amazon EKS, even when the VPC CNI plugin is installed, Kubernetes network policies must be explicitly enabled and configured to restrict inter-pod communication.

The vulnerability is classified under CWE-327 (Use of a Broken or Risky Cryptographic Algorithm), which in this context relates to the insecure default configuration allowing unauthorized access to sensitive data stored in Redis. An attacker who can deploy or compromise any pod within the same Kubernetes cluster can establish a direct connection to the Redis server, bypassing intended access controls.

Root Cause

The root cause of this vulnerability lies in the assumption that network isolation is automatically enforced in Kubernetes environments. Argo CD's Redis deployment does not implement authentication by default, and many Kubernetes networking solutions, including AWS VPC CNI, do not enforce network policies unless explicitly configured. This creates a gap between expected and actual security posture, where administrators may believe their Redis instance is protected when it is actually accessible from any pod in the cluster.

Attack Vector

The attack requires adjacent network access from within the same Kubernetes cluster. An attacker with the ability to deploy an unprivileged pod in any namespace can:

1. Discover the Argo CD Redis service through DNS or service enumeration
2. Connect directly to port 6379 using standard Redis clients
3. Extract cached credentials, session tokens, and application secrets
4. Modify Redis data to escalate privileges to cluster controller level
5. Potentially inject malicious configurations affecting GitOps deployments

The vulnerability exploits the lack of network segmentation between namespaces, allowing cross-namespace communication to sensitive Argo CD components. Once connected to Redis, an attacker can manipulate cached authentication data or extract sensitive information used by the Argo CD controller.

Detection Methods for CVE-2024-31989

Indicators of Compromise

• Unexpected network connections to port 6379 from pods outside the Argo CD namespace
• Redis command logs showing connections from unauthorized source IPs or pods
• Anomalous authentication events or privilege changes in Argo CD audit logs
• Unusual Redis operations such as key enumeration or bulk data extraction

Detection Strategies

• Implement Kubernetes network policy auditing to detect pods communicating across namespace boundaries
• Monitor Redis connection logs for connections originating from non-Argo CD pods
• Deploy runtime security tools to detect unauthorized network socket operations targeting port 6379
• Set up alerts for Redis commands that indicate reconnaissance activity such as KEYS *, SCAN, or CONFIG GET

Monitoring Recommendations

• Enable Kubernetes audit logging for network policy violations and cross-namespace traffic
• Configure Redis slowlog and connection monitoring to track all client connections
• Implement SentinelOne Kubernetes protection to monitor for suspicious pod-to-pod communications
• Regularly audit network policies to ensure Redis services are properly isolated

How to Mitigate CVE-2024-31989

Immediate Actions Required

• Upgrade Argo CD to patched versions: 2.8.19, 2.9.15, or 2.10.10
• Enable and configure Kubernetes network policies to restrict access to the Redis pod
• Implement Redis authentication using the --requirepass option or Redis ACLs
• Audit existing network policies to verify Argo CD namespace isolation

Patch Information

The vulnerability has been addressed in Argo CD versions 2.8.19, 2.9.15, and 2.10.10. Multiple commits have been released to fix this issue, including security improvements to network isolation and access controls. Organizations should upgrade to the latest patched version within their release branch. For detailed commit information, refer to the GitHub Security Advisory GHSA-9766-5277-j5hr and the associated ArgoCD commit fixes.

Workarounds

• Deploy Kubernetes NetworkPolicy resources to explicitly deny ingress to Redis from all namespaces except argocd
• Configure Redis with password authentication if patching is not immediately possible
• Use service mesh solutions like Istio to enforce mTLS between pods and restrict Redis access
• Consider deploying Argo CD in a dedicated cluster or with enhanced network isolation in critical environments

# Example Kubernetes NetworkPolicy to restrict Redis access
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: argocd-redis-network-policy
  namespace: argocd
spec:
  podSelector:
    matchLabels:
      app.kubernetes.io/name: argocd-redis
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app.kubernetes.io/part-of: argocd
    ports:
    - protocol: TCP
      port: 6379