IP Spoofing in Eclipse Kura Audit Logs

Executive Summary

Eclipse Kura versions prior to 5.6.2 have a vulnerability related to improper handling of the X-Forwarded-For HTTP header. The software trusts this client-supplied header as the authoritative source for the client IP address in audit log entries.

The components org.eclipse.kura.web2 (Web Console) and org.eclipse.kura.rest.provider (REST API) use this header to initialize audit context. Additionally, org.eclipse.kura.jetty.customizer installs Jetty's ForwardedRequestCustomizer on all HTTP/HTTPS connectors, which causes HttpServletRequest.getRemoteAddr() to return the attacker-controlled header value instead of the actual client IP address.

This allows an unauthenticated remote attacker to spoof the logged IP address. By doing so, they can bypass IP-based brute-force protections like fail2ban, enabling undetected brute-force attacks or causing a denial of service against a third party by injecting a victim's IP address and triggering a ban on that address.

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Detection Guidance

To detect this vulnerability, you can check if your Eclipse Kura instance is logging client IP addresses from the X-Forwarded-For header instead of the actual source IP. This can be done by examining audit logs or testing the behavior of the system.

• Inspect audit logs: Look for entries where the logged IP address does not match the expected source IP of the client. If the logged IP is a non-routable or unexpected value, it may indicate exploitation.
• Test with a spoofed X-Forwarded-For header: Send a request to the Eclipse Kura Web Console or REST API with a custom X-Forwarded-For header (e.g., using curl). For example: curl -H 'X-Forwarded-For: 192.0.2.1' http://<kura-instance>/endpoint. Check if the audit logs reflect the spoofed IP (192.0.2.1) instead of the actual source IP.
• Verify the installed version of Eclipse Kura: If the version is prior to 5.6.2, the system is vulnerable. You can check the version by reviewing the Kura installation or querying the system (e.g., via the Web Console or package manager).
• Check for the presence of Jetty's ForwardedRequestCustomizer: If the org.eclipse.kura.jetty.customizer component is enabled, it may indicate that the system is processing X-Forwarded-For headers unconditionally.

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Impact Analysis

• Bypass of IP-based brute-force protections: Attackers can spoof their IP address in audit logs, allowing them to conduct brute-force attacks (e.g., password guessing) without being blocked by tools like fail2ban.
• Undetected attacks: Since the real IP address is not logged, malicious activity may go unnoticed, increasing the risk of successful unauthorized access.
• Denial of service against third parties: Attackers can inject a victim's IP address into the logs, causing the victim to be falsely banned or blocked by security mechanisms.
• Compromised audit integrity: Audit logs will contain incorrect IP addresses, making it difficult to trace or investigate security incidents accurately.

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Compliance Impact

This vulnerability can impact compliance with standards and regulations in the following ways:

• GDPR (General Data Protection Regulation): Inaccurate audit logs may violate GDPR's requirements for data integrity and accountability (Article 5(1)(f) and Article 30). If logs are used to demonstrate compliance or investigate breaches, spoofed IP addresses could hinder these processes, potentially leading to non-compliance.
• HIPAA (Health Insurance Portability and Accountability Act): HIPAA requires covered entities to implement audit controls (45 CFR § 164.312(b)) to record and examine activity in systems containing protected health information (PHI). If audit logs are unreliable due to IP spoofing, this could result in non-compliance with HIPAA's audit requirements.
• Other standards: Many compliance frameworks, such as ISO 27001, NIST SP 800-53, and SOC 2, require accurate logging and monitoring of access to systems. This vulnerability undermines the reliability of logs, which could lead to non-compliance with these standards.

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Mitigation Strategies

To mitigate this vulnerability, follow these immediate steps:

• Upgrade to Eclipse Kura version 5.6.2 or later, as this version resolves the issue by properly handling the X-Forwarded-For header.
• If upgrading is not immediately possible, disable or modify the Jetty ForwardedRequestCustomizer in the org.eclipse.kura.jetty.customizer component to prevent it from processing the X-Forwarded-For header unconditionally. This may require custom configuration or code changes.
• Implement network-level controls to restrict access to the Eclipse Kura Web Console and REST API. Use firewalls or reverse proxies to filter or validate the X-Forwarded-For header before it reaches the Kura instance.
• Monitor audit logs for suspicious activity, such as repeated login attempts from unexpected or non-routable IP addresses. This can help detect ongoing exploitation attempts.
• Consider disabling IP-based brute-force protections like fail2ban if they rely on the logged IP address, as they may be ineffective or cause unintended denial-of-service against third parties. Replace them with alternative authentication or rate-limiting mechanisms.

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