How to remediate – XOOPS xoopsConfig[language] Parameter Local File Inclusion (XO…

1. Introduction

The XOOPS xoopsConfig[language] Parameter Local File Inclusion vulnerability affects PHP applications using the XOOPS content management system. This flaw allows attackers to read arbitrary local files on a compromised server, potentially leading to code execution with web server privileges. Systems running vulnerable versions of XOOPS are at risk. Successful exploitation could compromise confidentiality, integrity and availability of data.

2. Technical Explanation

• Exploit mechanism: An attacker crafts a malicious request containing a path to a local file, which is then included by XOOPS. For example, an attacker could submit a request with ‘xoopsConfig[language]=/etc/passwd’ to attempt reading the system password file.
• Scope: Affected platforms are web servers running PHP and XOOPS versions prior to fixes being applied.

3. Detection and Assessment

Confirming vulnerability involves checking the XOOPS version and PHP configuration. A thorough assessment requires testing for file inclusion.

• Quick checks: Check the XOOPS version in the admin interface or by examining the core files. Also, verify if ‘register_globals’ is enabled in your php.ini file using php -i | grep register_globals.
• Scanning: Nessus plugin ID 21879 may detect this vulnerability as an example.
• Logs and evidence: Examine web server logs for requests containing suspicious characters or paths within the ‘xoopsConfig[language]’ parameter. Look for include errors in PHP error logs.

php -i | grep register_globals

4. Solution / Remediation Steps

The primary solution is to disable ‘register_globals’ and enable ‘magic_quotes_gpc’ in the PHP configuration.

4.1 Preparation

• Ensure you have access to modify the php.ini file. A roll back plan involves restoring from backup or reverting the php.ini changes.

4.2 Implementation

1. Step 1: Edit the php.ini file (usually located in /etc/php5/apache2 or similar).
2. Step 2: Find the ‘register_globals’ setting and set it to Off.
3. Step 3: Find the ‘magic_quotes_gpc’ setting and set it to On.
4. Step 4: Save the php.ini file.
5. Step 5: Restart the web server service for the changes to take effect.

4.3 Config or Code Example

Before

register_globals = On
magic_quotes_gpc = Off

After

register_globals = Off
magic_quotes_gpc = On

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this type of vulnerability.

• Practice 2: Least privilege limits the impact if an attacker successfully exploits a vulnerability like this one.

4.5 Automation (Optional)

If using configuration management tools, automate the changes to php.ini.

# Example Ansible task
- name: Disable register_globals and enable magic_quotes_gpc in php.ini
  lineinfile:
    path: /etc/php5/apache2/php.ini
    regexp: '^(register_globals|magic_quotes_gpc)'
    lines:
      - register_globals = Off
      - magic_quotes_gpc = On
  notify: Restart Apache

5. Verification / Validation

Confirm the fix by checking PHP configuration and retesting for file inclusion.

• Post-fix check: Run php -i | grep register_globals and verify that it returns ‘register_globals = Off’.
• Monitoring: Monitor web server logs for any unexpected errors related to include functions.

php -i | grep register_globals

6. Preventive Measures and Monitoring

Regular security baselines and pipeline checks can help prevent this issue.

• Baselines: Update your PHP security baseline to include disabling ‘register_globals’ and enabling ‘magic_quotes_gpc’.
• Pipelines: Integrate SAST tools into your CI/CD pipeline to scan for insecure code patterns, including missing input validation.
• Asset and patch process: Implement a regular patch review cycle for XOOPS and its dependencies.

7. Risks, Side Effects, and Roll Back

Disabling ‘register_globals’ may cause compatibility issues with older applications that rely on it. Enabling ‘magic_quotes_gpc’ is deprecated in newer PHP versions.

• Risk or side effect 2: ‘magic_quotes_gpc’ is deprecated and may be removed in future PHP versions. Mitigation: Plan to migrate away from using this setting as soon as possible.
• Roll back: Restore the original php.ini file from your backup, then restart the web server service.

8. References and Resources

Links only to sources that match this exact vulnerability.

• Vendor advisory or bulletin: http://retrogod.altervista.org/xoops_xpl.html
• NVD or CVE entry: CVE-2005-3680
• Product or platform documentation relevant to the fix: No specific documentation found for this vulnerability, refer to general XOOPS security guidelines.