How to remediate – RunCMS xoopsOption Parameter Local File Inclusion

1. Introduction

RunCMS xoopsOption Parameter Local File Inclusion is a vulnerability in the RunCMS PHP application that allows an attacker to potentially view arbitrary files or execute code on a server. This affects websites using RunCMS and could lead to data breaches, website defacement, or complete system compromise. Systems running vulnerable versions of RunCMS are at risk. The likely impact is high confidentiality, medium integrity, and medium availability.

2. Technical Explanation

• Root cause: Missing input validation of the ‘xoopsOption[pagetype]’ parameter prior to inclusion in ‘include/common.php’.
• Exploit mechanism: An attacker can craft a malicious request containing a path to an arbitrary file on the server, which will then be included and executed by the application. For example, sending a request with ‘xoopsOption[pagetype]=/etc/passwd’ could reveal system password information.
• Scope: RunCMS versions prior to a currently unknown patched version are affected.

3. Detection and Assessment

You can confirm if your system is vulnerable by checking the installed RunCMS version and looking for evidence of exploitation attempts in web server logs.

• Quick checks: Check the RunCMS version via the admin interface or by examining files like ‘include/version.php’.
• Scanning: Nessus plugin ID 26562 can detect this vulnerability. This is an example only, and results should be verified manually.
• Logs and evidence: Examine web server access logs for requests containing suspicious parameters in the URL, such as ‘xoopsOption[pagetype]’ followed by file paths. Look for errors related to including files that do not exist.

php -v # Check PHP version; older versions may be more susceptible.

4. Solution / Remediation Steps

Currently, there is no known solution available at this time. The following steps outline a process for monitoring and potential mitigation until a patch is released.

4.1 Preparation

• Ensure you have access to restore the backup in case of issues. A roll back plan involves restoring from the previous backup.
• A change window may be required depending on your organisation’s policies and risk tolerance. Approval from a senior IT administrator is recommended.

4.2 Implementation

1. Step 1: Monitor web server logs for suspicious activity related to the ‘xoopsOption[pagetype]’ parameter.
2. Step 2: Implement a Web Application Firewall (WAF) rule to block requests containing potentially malicious file paths in the ‘xoopsOption[pagetype]’ parameter.
3. Step 3: Regularly scan your system for new vulnerabilities and updates related to RunCMS.

4.3 Config or Code Example

Before

# No input validation on xoopsOption[pagetype] parameter

After

# Implement input validation and sanitisation of xoopsOption[pagetype] parameter before inclusion. (Example - not specific to RunCMS)
if (!preg_match('/^[a-zA-Z0-9_-]+$/', $_GET['xoopsOption']['pagetype'])) {
  // Log the attempt and reject the request
}

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this type of vulnerability. Input validation is crucial for blocking malicious data. Least privilege limits the impact if an attacker gains access. Patch cadence ensures systems are up-to-date with the latest security fixes.

• Practice 1: Implement strict input validation on all user-supplied data to prevent injection attacks.
• Practice 2: Apply the principle of least privilege, ensuring that web server processes have only the necessary permissions to function.

4.5 Automation (Optional)

# Example WAF rule using ModSecurity:
SecRule REQUEST_URI "@rx ^/.*xoopsOption[pagetype]=.*" "id:9001,phase:2,deny,log,status:403"

5. Verification / Validation

• Post-fix check: Attempt a request with ‘xoopsOption[pagetype]=/etc/passwd’ and verify that it is blocked by the WAF or results in an error.
• Re-test: Repeat the earlier detection method (examining web server logs) to confirm that suspicious requests are no longer successful.
• Monitoring: Monitor web server access logs for any further attempts to exploit the vulnerability or similar patterns.

# Example command to check WAF logs (syntax varies by WAF):
grep "id:9001" /var/log/apache2/modsec_audit.log # Check ModSecurity audit log for blocked requests

6. Preventive Measures and Monitoring

• Baselines: Update your web server security baseline to include rules for blocking common injection attacks, such as local file inclusion.
• Asset and patch process: Implement a monthly patch review cycle for all web applications, including RunCMS.

7. Risks, Side Effects, and Roll Back

Implementing WAF rules may cause false positives, blocking legitimate requests. Incorrectly configured rules could disrupt website functionality. Roll back by removing the WAF rule or adjusting its configuration.

• Risk or side effect 1: False positives from WAF rules can block legitimate user traffic. Mitigation involves carefully tuning the rules and monitoring for errors.
• Roll back: Step 1: Remove the implemented WAF rule. Step 2: Restore the web server configuration from a previous backup if necessary.

8. References and Resources

• Vendor advisory or bulletin: SecurityFocus BID 26562
• NVD or CVE entry: No specific CVE is currently associated with this vulnerability, but it can be referenced via the SecurityFocus BID.
• Product or platform documentation relevant to the fix: Refer to RunCMS official documentation for updates and security advisories (when available).