1. Introduction
The osCommerce application_top.php Multiple Parameter HTTP Response splitting vulnerability allows an attacker to inject malicious text into HTTP headers. This can lead to session identifier theft and misrepresentation of the affected website, potentially compromising user accounts and trust. This affects websites running vulnerable versions of the osCommerce e-commerce platform. A successful exploit could impact confidentiality, integrity, and availability.
2. Technical Explanation
The vulnerability occurs because osCommerce fails to properly sanitise user input in several parameters within the ‘includes/application_top.php’ script and the ‘goto’ parameter of the ‘banner.php’ script. This allows attackers to inject HTTP response headers, controlling how a browser interprets the server’s output. CVE-2005-1951 describes this issue.
- Root cause: Insufficient input validation in osCommerce scripts when handling user-supplied parameters.
- Exploit mechanism: An attacker crafts a malicious URL containing injected HTTP header data within vulnerable parameters, which is then processed by the server and sent to the client’s browser. For example, an attacker could inject a ‘Location’ header to redirect users to a phishing site.
- Scope: Affected versions of osCommerce are not explicitly defined in the provided context but require investigation based on your specific installation.
3. Detection and Assessment
Confirming vulnerability requires checking the version of osCommerce installed and assessing if input sanitisation is present in relevant scripts.
- Quick checks: Check the osCommerce admin panel for the current version number, or inspect the ‘includes/application_top.php’ file for evidence of input validation functions around parameter handling.
- Scanning: Nessus vulnerability ID 3f295f7d may detect this issue as an example only.
- Logs and evidence: Examine web server access logs for unusual HTTP header patterns or redirects originating from the affected osCommerce instance.
grep -i "application_top.php" /path/to/oscommerce/includes/ | grep -i "sanitize" 4. Solution / Remediation Steps
Currently, a specific solution is unknown. The following steps outline general best practices and investigation procedures.
4.1 Preparation
- Back up the entire osCommerce installation, including database and files. Stop the web server service if possible to prevent further exploitation during analysis.
- Ensure you have a rollback plan in place by restoring from your backup if issues arise.
- A change window may be needed depending on the size of the site and potential impact. Approval from relevant stakeholders is recommended.
4.2 Implementation
- Step 1: Download the latest version of osCommerce, if available. Compare its ‘includes/application_top.php’ file to your current version.
- Step 2: Identify differences in input sanitisation routines and apply them to your existing installation.
4.3 Config or Code Example
Before
//Example - insecure code (may not be exact)
$parameter = $_GET['param'];
echo $parameter;
After
//Example - secure code (may not be exact)
$parameter = isset($_GET['param']) ? htmlspecialchars($_GET['param']) : '';
echo $parameter;
4.4 Security Practices Relevant to This Vulnerability
Several security practices can mitigate this type of vulnerability.
- Practice 2: Least privilege limits the impact if an attacker gains control. Ensure web server processes run with minimal necessary permissions.
4.5 Automation (Optional)
No automation steps are provided due to the lack of a specific fix and the need for careful code review.
5. Verification / Validation
Confirming the fix requires re-testing with the original exploit conditions and verifying that malicious headers are no longer injected.
- Post-fix check: Check the website version number to confirm the updated ‘includes/application_top.php’ file is in place.
- Re-test: Attempt to inject HTTP header data through vulnerable parameters using a crafted URL and verify that it does not appear in the server’s response headers.
- Smoke test: Verify core website functionality, such as browsing products, adding items to the cart, and completing checkout, is still working correctly.
- Monitoring: Monitor web server logs for any unusual HTTP header patterns or redirects.
curl -I "http://your-oscommerce-site.com/index.php?param=" 6. Preventive Measures and Monitoring
Proactive measures can reduce the risk of similar vulnerabilities.
- Baselines: Implement a security baseline that requires input validation for all web applications.
- Asset and patch process: Establish a regular patch review cycle for osCommerce and other e-commerce platforms.
7. Risks, Side Effects, and Roll Back
Applying changes carries some risk.
- Risk or side effect 2: Compatibility issues may arise with existing osCommerce modules or extensions.
- Roll back: Restore the original ‘includes/application_top.php’ file and database backup if issues occur. Restart the web server service.
8. References and Resources
- Vendor advisory or bulletin: No specific vendor advisory is available in the provided context.
- NVD or CVE entry: CVE-2005-1951
- Product or platform documentation relevant to the fix: Consult the official osCommerce documentation for input validation best practices.