CVE-2025-1098
Remediation/Mitigation Strategy for CVE-2025-1098 - Ingress-Nginx Configuration Injection Vulnerability
This document outlines the remediation and mitigation strategies for CVE-2025-1098, a critical vulnerability affecting ingress-nginx.
1. Vulnerability Description:
- Vulnerability: Configuration Injection via
mirror-targetandmirror-hostIngress annotations. - Affected Component: ingress-nginx controller.
- Description: The
mirror-targetandmirror-hostIngress annotations in ingress-nginx allow for the injection of arbitrary configuration into the Nginx configuration file. This injection can be leveraged to execute arbitrary code within the ingress-nginx controller’s context. Crucially, this can lead to the disclosure of Secrets accessible to the controller, which, in default installations, can include all Secrets cluster-wide.
2. Severity:
- CVSS Score: 8.8 (High)
- Impact:
- Arbitrary Code Execution: Attackers can execute arbitrary code within the ingress-nginx controller’s pod.
- Secrets Disclosure: Attackers can gain access to sensitive data stored in Kubernetes Secrets, potentially including credentials, API keys, and other confidential information.
- Cluster Compromise: Given the widespread permissions often granted to ingress-nginx controllers, a successful exploit could lead to full cluster compromise.
3. Known Exploit(s):
- The CVE description states that the vulnerability allows for arbitrary code execution and Secret disclosure. Specific proof-of-concept exploits may exist publicly or privately. Actively research available exploits to understand potential attack vectors and refine mitigation strategies. While the information provided doesn’t include a specific exploit, the description strongly suggests that crafting malicious
mirror-targetormirror-hostvalues to execute commands is the most likely attack vector.
4. Remediation Strategy:
The primary remediation step is to update to a patched version of ingress-nginx that addresses this vulnerability.
Immediate Action:
- Upgrade ingress-nginx: Upgrade your ingress-nginx controller to a version that includes the fix for CVE-2025-1098. Consult the official ingress-nginx documentation and release notes for the correct upgrade path. This is the MOST IMPORTANT step. The ingress-nginx project will have specific versions that contain the necessary security patches.
- Identify Affected Ingresses: Audit all existing Ingress resources in your cluster to identify those using the
mirror-targetandmirror-hostannotations. This allows you to prioritize patching efforts based on the potential blast radius. Document these Ingresses.
Upgrade Procedure:
- Backup: Back up your existing ingress-nginx configuration before performing the upgrade. This includes Ingress resources, ConfigMaps, and any custom configurations.
- Staging Environment: Test the upgrade in a staging (non-production) environment first. Verify that all applications function correctly after the upgrade.
- Production Upgrade: Once validated in staging, upgrade the ingress-nginx controller in your production environment. Monitor the upgrade process closely for any errors or disruptions.
- Post-Upgrade Verification: After the upgrade, thoroughly test the functionality of your Ingress resources and monitor for any unexpected behavior.
5. Mitigation Strategy (In addition to Remediation - for defense in depth and until upgrades are complete):
Even after upgrading, consider these mitigation steps to reduce the risk:
Principle of Least Privilege:
- Restrict ingress-nginx Permissions: Carefully review and restrict the RBAC permissions granted to the ingress-nginx controller. Minimize the scope of Secrets that the controller can access. Consider using namespace-scoped controllers where possible to limit access to Secrets within specific namespaces. Specifically, examine any ClusterRoleBindings or RoleBindings that grant the ingress-nginx service account broad privileges.
- Pod Security Policies (PSP) / Pod Security Admission (PSA): Implement PSPs (deprecated but still relevant in some clusters) or PSA to restrict the capabilities of the ingress-nginx controller pods. For example, prevent privilege escalation and restrict the use of host namespaces.
Input Validation and Sanitization (if applicable):
- While the vulnerability lies in configuration injection, explore whether any form of input validation can be implemented on the values passed to
mirror-targetandmirror-hostvia admission controllers or other mechanisms. However, this is a complex approach and should not be relied upon as the primary mitigation. Focus on upgrading.
- While the vulnerability lies in configuration injection, explore whether any form of input validation can be implemented on the values passed to
Network Segmentation:
- Segment the network to limit the impact of a compromised ingress-nginx controller. Restrict communication between the ingress-nginx pods and other sensitive components within the cluster. Use NetworkPolicies to control network traffic.
Monitoring and Alerting:
- Anomaly Detection: Implement monitoring and alerting to detect unusual activity within the ingress-nginx controller. This could include:
- Unexpected process execution.
- Unauthorized access to Secrets.
- Unusual network traffic patterns.
- Log Analysis: Aggressively log and analyze ingress-nginx controller logs for suspicious activity, such as failed attempts to access Secrets or unexpected configuration changes. Configure alerts based on log patterns indicative of exploitation attempts.
- Regular Security Audits: Conduct regular security audits of your Kubernetes cluster, including the ingress-nginx configuration, RBAC permissions, and network policies.
- Anomaly Detection: Implement monitoring and alerting to detect unusual activity within the ingress-nginx controller. This could include:
Web Application Firewall (WAF):
- While not a direct mitigation for the configuration injection, a WAF placed in front of the ingress controller can provide an additional layer of defense against malicious requests. Configure the WAF to detect and block common web attacks that might be used to exploit the vulnerability.
6. Long-Term Prevention:
- Secure Development Practices: Emphasize secure coding practices during the development and maintenance of Ingress controllers and Kubernetes configurations.
- Regular Security Training: Provide regular security training to developers, operators, and security personnel to raise awareness of common vulnerabilities and secure configuration practices.
- Automated Security Scanning: Implement automated security scanning tools to identify vulnerabilities in Kubernetes configurations and Ingress resources.
- Stay Informed: Subscribe to security advisories from the ingress-nginx project and other relevant sources to stay informed about new vulnerabilities and security best practices.
7. Communication:
- Clearly communicate the vulnerability and remediation plan to all relevant stakeholders, including developers, operations teams, and security personnel.
- Provide regular updates on the progress of the remediation efforts.
Important Considerations:
- Prioritize the Upgrade: The upgrade to a patched version is the most critical step. Do not rely solely on mitigation strategies as a substitute for patching.
- Test Thoroughly: Thorough testing is essential to ensure that the upgrade and mitigation steps do not introduce any unintended side effects.
- Monitor Continuously: Continuous monitoring and alerting are crucial for detecting and responding to any exploitation attempts.
- Defense in Depth: Implement a layered security approach that combines remediation and mitigation strategies to provide multiple layers of protection.
Assigner
- Kubernetes [email protected]
Date
- Published Date: 2025-03-24 23:29:16
- Updated Date: 2025-03-25 00:15:15