1. Introduction
The vBulletin search.php query parameter is vulnerable to a cross-site scripting attack. This means an attacker could inject malicious code into the website, potentially stealing user cookies and gaining unauthorised access. This affects websites running the vBulletin PHP application. A successful exploit may compromise confidentiality of user data.
2. Technical Explanation
The vulnerability occurs due to insufficient input validation in the search.php script when handling query parameters. An attacker can craft a malicious URL containing JavaScript code that is then executed by other users’ browsers when they visit the affected page. The CVE identifier for this issue is CVE-2004-2076. A simple example involves injecting a script tag into the search query to steal cookies.
- Root cause: Missing or inadequate sanitisation of user input in the search query parameter.
- Exploit mechanism: An attacker crafts a URL with malicious JavaScript code within the search query, which is then executed by users visiting that link. For example:
http://example.com/search.php?query= - Scope: vBulletin PHP application versions prior to any patched release.
3. Detection and Assessment
Confirming vulnerability requires checking the installed vBulletin version and testing the search functionality with potentially malicious input.
- Quick checks: Check the vBulletin version in the admin control panel under “Server Information”.
- Scanning: Nessus plugin ID 10632 may detect this issue, but results should be verified manually.
- Logs and evidence: Examine web server access logs for requests containing suspicious JavaScript code within the search query parameter.
# No specific command available to confirm exposure directly. Check version via admin panel.4. Solution / Remediation Steps
Currently, there is no known solution at this time. Mitigation focuses on limiting access and monitoring for exploitation attempts.
4.1 Preparation
- No services need to be stopped at this time, but monitor resource usage closely during testing. A roll back plan involves restoring from backup.
- Change windows are not required as no fix is available. Approval may be needed for any monitoring changes.
4.2 Implementation
- Step 1: Implement strict input validation and output encoding on all user-supplied data, especially within the search functionality. This requires code modification which is outside of scope without a patch.
- Step 2: Consider using a web application firewall (WAF) to filter out malicious requests containing XSS payloads.
4.3 Config or Code Example
Before
# No code example available as no patch exists. The vulnerability is in the core search functionality of vBulletin.After
# No code example available as no patch exists. Implement input validation and output encoding where possible.4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent this type of vulnerability.
- Practice 2: Output encoding prevents injected code from being executed by the browser.
4.5 Automation (Optional)
No automation steps are available as no patch exists.
# No automation script is available at this time.5. Verification / Validation
- Post-fix check: Attempt to inject a JavaScript payload into the search query and verify that it does not execute in the browser.
- Re-test: Re-run the earlier detection method (attempting XSS injection) to confirm the issue is resolved.
- Monitoring: Monitor web server logs for any attempts to inject malicious code into the search query parameter.
# No specific command available. Test by attempting XSS injection and verifying no execution.6. Preventive Measures and Monitoring
Regular security assessments and a robust patch management process are essential.
- Baselines: Update your web application security baseline to include input validation and output encoding requirements.
- Pipelines: Implement static analysis tools (SAST) in your CI/CD pipeline to detect potential XSS vulnerabilities during development.
- Asset and patch process: Establish a regular schedule for reviewing and applying security patches to all software, including vBulletin.
7. Risks, Side Effects, and Roll Back
Implementing mitigation measures may introduce compatibility issues or performance overhead.
- Risk or side effect 2: WAF rules can sometimes cause false positives, blocking valid traffic. Monitor WAF logs closely and adjust rules as needed.
8. References and Resources
Links to official advisories and trusted documentation.
- Vendor advisory or bulletin: https://www.securityfocus.com/archive/1/353869
- NVD or CVE entry: CVE-2004-2076
- Product or platform documentation relevant to the fix: No specific documentation available as no patch exists.