CVE-2024-22030: Rancher Information Disclosure Flaw

CVE-2024-22030 Overview

A vulnerability has been identified within Rancher that can be exploited in narrow circumstances through a man-in-the-middle (MITM) attack. An attacker would need to have control of an expired domain or execute a DNS spoofing/hijacking attack against the domain to exploit this vulnerability. The targeted domain is the one used as the Rancher URL.

Critical Impact

Successful exploitation allows an attacker to intercept and manipulate communications between Rancher components, potentially leading to complete cluster compromise with high confidentiality, integrity, and availability impact across multiple systems.

Affected Products

• Rancher (affected versions - see security advisory for details)
• Rancher Kubernetes Management Platform
• Systems using Rancher URL configurations with improperly validated certificates

Discovery Timeline

• 2024-10-16 - CVE CVE-2024-22030 published to NVD
• 2024-10-16 - Last updated in NVD database

Technical Details for CVE-2024-22030

Vulnerability Analysis

This vulnerability is classified under CWE-295 (Improper Certificate Validation), indicating that Rancher fails to properly validate SSL/TLS certificates in certain scenarios. The flaw enables man-in-the-middle attacks when an attacker can control the domain resolution for the Rancher URL.

The attack requires network access and high-level privileges within the target environment, but once successfully exploited, the scope extends beyond the vulnerable component to affect other systems in the environment. This cross-scope impact means that a compromised Rancher instance can be leveraged to attack managed Kubernetes clusters and their workloads.

Root Cause

The root cause of this vulnerability lies in improper certificate validation (CWE-295) within Rancher's communication handling. When the Rancher URL domain expires or is subject to DNS manipulation, the application does not adequately verify certificate authenticity, allowing attackers to present fraudulent certificates that are incorrectly trusted.

This validation gap exists in the communication path between Rancher and its managed components, where certificate pinning or strict validation mechanisms are either absent or insufficient. The vulnerability specifically affects scenarios where:

1. The domain used for Rancher URL has expired and been re-registered by an attacker
2. DNS spoofing or hijacking redirects legitimate Rancher URL requests to attacker-controlled infrastructure

Attack Vector

The attack is network-based and requires an attacker to first establish control over the domain resolution for the Rancher URL. This can be accomplished through:

1. Expired Domain Takeover: If the domain used for the Rancher URL expires, an attacker can register it and set up a malicious server with a valid certificate for that domain.

2. DNS Spoofing/Hijacking: Through DNS cache poisoning, BGP hijacking, or compromising DNS infrastructure, an attacker can redirect Rancher URL requests to malicious infrastructure.

Once DNS control is established, the attacker positions themselves between Rancher components to intercept, modify, or inject malicious communications. Due to the improper certificate validation, Rancher trusts the attacker's server, enabling credential theft, configuration manipulation, and potential remote code execution within managed clusters.

For detailed technical analysis, refer to the GitHub Security Advisory GHSA-h4h5-9833-v2p4.

Detection Methods for CVE-2024-22030

Indicators of Compromise

• Unexpected changes to DNS records for Rancher URL domains
• Certificate warnings or SSL/TLS handshake failures in Rancher component logs
• Anomalous network traffic patterns between Rancher server and managed clusters
• Authentication failures or unexpected credential reset events

Detection Strategies

• Monitor DNS resolution logs for the Rancher URL domain to detect unauthorized changes
• Implement certificate transparency monitoring for domains associated with Rancher infrastructure
• Deploy network intrusion detection systems (IDS) to identify potential MITM attack patterns
• Enable comprehensive logging of Rancher API calls and authentication events

Monitoring Recommendations

• Configure alerting on domain expiration dates for all domains used in Rancher configurations
• Implement DNSSEC validation for Rancher URL domains where possible
• Monitor for unexpected certificate changes using certificate transparency logs
• Deploy network flow analysis to detect anomalous traffic patterns to/from Rancher infrastructure

How to Mitigate CVE-2024-22030

Immediate Actions Required

• Verify that all domains used for Rancher URLs are valid and not expired
• Review and validate current DNS configurations for Rancher-related domains
• Audit network traffic for signs of MITM attacks or DNS manipulation
• Check for security patches from Rancher and apply immediately

Patch Information

SUSE and the Rancher project have released security advisories addressing this vulnerability. Organizations should consult the GitHub Security Advisory GHSA-h4h5-9833-v2p4 and SUSE Bugzilla CVE-2024-22030 for specific patch versions and update instructions. Apply the latest security updates to all Rancher installations.

Workarounds

• Implement certificate pinning for Rancher communications where possible
• Enable DNSSEC for all domains used in Rancher URL configurations
• Use private DNS infrastructure with strict access controls for Rancher domains
• Configure network segmentation to limit exposure of Rancher management interfaces

# Configuration example - Enable DNSSEC validation (example for BIND DNS)
options {
    dnssec-enable yes;
    dnssec-validation auto;
};

# Verify domain ownership and expiration
whois your-rancher-domain.com | grep -E "(Expiry|Expiration)"

# Monitor certificate transparency logs
# Use Google Certificate Transparency search
# https://transparencyreport.google.com/https/certificates