How to remediate – Kodi Local File Inclusion Information Disclosure

1. Introduction

The Kodi Local File Inclusion Information Disclosure vulnerability affects media player servers running on the remote host. This is a security flaw where an attacker can access files on the server they shouldn’t be able to see, potentially exposing sensitive information like configuration details or user data. Systems running the Kodi media player with the Chorus web interface are typically affected. Successful exploitation could lead to confidential data disclosure.

2. Technical Explanation

The vulnerability stems from improper validation of user-supplied input within the Chorus web interface’s /image/ script, specifically when path traversal characters (like %2F) are used in URLs. This allows an attacker to manipulate file paths and access arbitrary files on the server. The CVE associated with this issue is CVE-2017-5982.

• Root cause: Insufficient input validation within the /image/ script of the Chorus web interface.
• Exploit mechanism: An attacker crafts a malicious URL containing path traversal characters to access files outside the intended directory. For example, an attacker could use a URL like http://example.com/image/%2Fetc/passwd to attempt to read the /etc/passwd file.
• Scope: Kodi media player servers running with the Chorus web interface are affected.

3. Detection and Assessment

To confirm vulnerability, check the version of Kodi installed and verify if the Chorus web interface is enabled. A thorough method involves attempting to access files outside the intended directory using a crafted URL.

• Quick checks: Check the Kodi version by accessing the system information within the Kodi user interface or via command line (if available).
• Scanning: Nessus and OpenVAS may identify this vulnerability with plugin IDs depending on their current definitions. These are examples only, as scanner coverage varies.
• Logs and evidence: Examine web server logs for requests containing path traversal characters (%2F) targeting the /image/ script. Look for error messages related to file access attempts.

# Example command placeholder:
# No specific command available without knowing Kodi installation details. Check system information within Kodi UI.

4. Solution / Remediation Steps

Currently, there is no official solution available for this vulnerability. Contact the vendor for a fix or workaround.

4.1 Preparation

• Ensure you have a rollback plan in place, which involves restoring the backed-up configuration.

4.2 Implementation

1. Step 1: Contact Kodi developers or support to request a fix or workaround.
2. Step 2: Monitor the Kodi website and security mailing lists for updates regarding this vulnerability.
3. Step 3: If a patch is released, download and apply it according to the vendor’s instructions.

4.3 Config or Code Example

No config or code example available as there is no current fix.

Before

After

4.4 Security Practices Relevant to This Vulnerability

Implementing input validation and least privilege principles can help mitigate this vulnerability type.

• Practice 1: Input validation prevents malicious data from being processed, blocking path traversal attempts.
• Practice 2: Least privilege limits the impact of exploitation by reducing the attacker’s access to sensitive files.

4.5 Automation (Optional)

No automation steps are available at this time due to the lack of a fix.

5. Verification / Validation

• Post-fix check: Attempting to access files outside the intended directory should now return an error message or a 403 Forbidden status code.
• Re-test: Repeat the steps from the “Detection and Assessment” section. The attempt to read /etc/passwd (or another sensitive file) should fail.
• Smoke test: Ensure that basic Kodi functionality, such as playing media files, continues to work as expected.
• Monitoring: Monitor web server logs for any suspicious requests targeting the /image/ script.

# Example command placeholder:
# Attempt access via crafted URL and verify error response.

6. Preventive Measures and Monitoring

Regular security baselines and secure coding practices can help prevent similar vulnerabilities in the future.

• Baselines: Update your security baseline to include input validation requirements for web applications.
• Pipelines: Integrate Static Application Security Testing (SAST) into your CI/CD pipeline to identify potential vulnerabilities during development.
• Asset and patch process: Implement a regular patch review cycle to ensure timely application of security updates.

7. Risks, Side Effects, and Roll Back

Applying workarounds from the vendor may introduce compatibility issues or service disruptions. Always have a rollback plan in place.

• Risk or side effect 1: Workarounds might cause unexpected behavior with certain Kodi features.
• Risk or side effect 2: Applying patches could temporarily interrupt service availability.
• Roll back: Restore the backed-up Kodi configuration to revert any changes made during remediation.

8. References and Resources

Refer to official advisories for accurate information about this vulnerability.

• Vendor advisory or bulletin: https://www.exploit-db.com/exploits/41312/
• NVD or CVE entry: CVE-2017-5982
• Product or platform documentation relevant to the fix: No specific documentation available at this time.