1. Introduction
Vanilla Forum p Parameter Local File Inclusion is a vulnerability in Vanilla Forums, an open source forum software. It allows attackers to view arbitrary files on a server running the affected PHP script, and potentially execute code. This affects websites using Vanilla Forums as their discussion platform. Successful exploitation could lead to data breaches, website defacement, or complete system compromise. Confidentiality, integrity, and availability are all at risk.
2. Technical Explanation
The vulnerability occurs because the ‘index.php’ script doesn’t properly sanitise input passed via the ‘p’ parameter. It uses this input to construct a file path using PHP’s ‘require_once()’ function. On Windows systems, attackers can use backslashes (”) as directory separators in traversal sequences within the ‘p’ parameter to access files outside of the intended web root. There is no known CVE or CVSS score at this time.
- Root cause: Insufficient input validation on the ‘p’ parameter when constructing file paths for inclusion.
- Exploit mechanism: An attacker crafts a malicious URL containing a specially formed ‘p’ parameter with backslash characters to access arbitrary files. For example, `http://example.com/index.php?p=/../../../../../etc/passwd`.
- Scope: Vanilla Forums running on Windows servers are affected. The specific versions impacted have not been fully documented publicly.
3. Detection and Assessment
Confirming vulnerability requires checking the installed version of Vanilla Forums and testing for file inclusion.
- Quick checks: Check the Vanilla Forums admin panel for the software version. Look for any recent updates or security notices on the official website.
- Scanning: Nessus plugins 8606f33c and dc922728 may identify this vulnerability, but results should be verified manually.
- Logs and evidence: Examine web server access logs for requests containing suspicious ‘p’ parameter values with backslash characters. Look for attempts to access files outside the expected web root directory.
# Example command placeholder:
# No specific command available without knowing the server setup. Check web server logs as described above.
4. Solution / Remediation Steps
A solution is currently unknown. The following steps are preparatory in case a patch becomes available or for mitigating the risk through other means.
4.1 Preparation
- Services to stop: Stop the web server service (e.g., Apache, IIS) during the update process. A roll back plan involves restoring from the pre-update backup.
- Dependencies or prerequisites: Ensure you have access to the Vanilla Forums files and a method for deploying updates. Change windows may be needed depending on your environment.
4.2 Implementation
- Step 1: Monitor the official Vanilla Forums website and security mailing lists for patch releases.
- Step 2: Once a patch is available, download it from the official source.
- Step 3: Stop the web server service.
- Step 4: Replace the existing Vanilla Forums files with the patched version.
- Step 5: Start the web server service.
4.3 Config or Code Example
Before
# No code example available as the vulnerability is in core logic. The vulnerable code resides within library/core/class.dispatcher.php.
After
# No code example available, awaiting a patch release from Vanilla Forums.
4.4 Security Practices Relevant to This Vulnerability
Several security practices can help reduce the risk of this type of vulnerability.
- Practice 2: Least privilege ensures that even if an attacker gains access, they are limited by the permissions of the web server process.
4.5 Automation (Optional)
No automation is available at this time due to the lack of a patch.
# No script provided as there's no automated fix currently available.
5. Verification / Validation
- Post-fix check: Check the Vanilla Forums version number to confirm the patch was applied successfully.
- Monitoring: Monitor web server access logs for any suspicious activity related to file inclusion attempts.
# Post-fix command and expected output:
# Check Vanilla Forums version in admin panel - confirm patched version number is displayed.
6. Preventive Measures and Monitoring
Implementing robust security measures can help prevent similar vulnerabilities.
- Baselines: Update your server baseline to include secure coding practices, such as input validation and least privilege.
- Pipelines: Integrate Static Application Security Testing (SAST) into your development pipeline to identify potential vulnerabilities early on.
- Asset and patch process: Establish a regular patch review cycle for all software components, including Vanilla Forums.
7. Risks, Side Effects, and Roll Back
Applying the patch may introduce compatibility issues or service disruptions.
- Risk or side effect 2: Downtime is required during the update process. Schedule maintenance windows accordingly.
- Roll back: Restore the Vanilla Forums database and web root directory from the pre-update backup. Restart the web server service.
8. References and Resources
Links to resources related to this vulnerability.
- Vendor advisory or bulletin: http://www.nessus.org/u?8606f33c
- NVD or CVE entry: No CVE available at this time.
- Product or platform documentation relevant to the fix: http://www.securityfocus.com/bid/47873