How to remediate – WANem result.php pc Parameter Remote Command Execution

1. Introduction

The WANem result.php pc Parameter Remote Command Execution vulnerability affects web servers running a vulnerable version of WANem. This allows an attacker to run commands on the server, potentially gaining full control. Systems hosting WANem instances are at risk, with potential impact to confidentiality, integrity and availability depending on the privileges gained by an attacker.

2. Technical Explanation

The vulnerability exists because the result.php script does not properly validate user-supplied input for the ‘pc’ parameter. An attacker can send a crafted request containing malicious commands within this parameter, which are then executed on the server. Exploitation requires network access to the WANem web interface and is considered remote.

• Root cause: Insufficient input validation of the ‘pc’ parameter in the result.php script.
• Exploit mechanism: An attacker sends a HTTP request with a malicious command injected into the ‘pc’ parameter, which is then executed by the server. For example, an attacker could send a crafted URL like http://target/result.php?pc=whoami to execute the ‘whoami’ command.
• Scope: WANem web servers are affected. Specific versions were not provided in the context.

3. Detection and Assessment

Confirming vulnerability requires checking the WANem version running on your systems, or testing for the remote execution capability.

• Quick checks: Access the WANem web interface and check its ‘About’ page to identify the installed version.
• Scanning: Nessus ID 60995f52 can detect this vulnerability. This is provided as an example only.
• Logs and evidence: Examine web server logs for requests containing suspicious characters or commands in the ‘pc’ parameter of result.php. Specific log paths will depend on your WANem configuration.

# No specific command available without knowing WANem version/config

4. Solution / Remediation Steps

There is currently no known patch for this vulnerability. The recommended approach is to disable or restrict access to the affected application.

4.1 Preparation

• Dependencies: None known. Roll back plan involves restoring the previous WANem configuration and restarting the web server.
• Change window needs: A standard change window is recommended due to potential service disruption. Approval from a system owner may be required.

4.2 Implementation

1. Step 1: Disable access to the result.php script via your web server configuration (e.g., Apache .htaccess, Nginx config).
2. Step 2: If disabling is not possible, restrict access to only trusted IP addresses using firewall rules or web application firewall policies.

4.3 Config or Code Example

Before

# No specific config example available without knowing web server type

After

# Example Apache .htaccess rule to deny access:
<Files result.php>
  Order Deny,Allow
  Deny from all
</Files>

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. Run web applications with minimal necessary permissions.

4.5 Automation (Optional)

No specific automation script is provided due to the lack of version information and differing WANem configurations.

# No suitable automation snippet available

5. Verification / Validation

Confirming the fix involves verifying that access to result.php is blocked or restricted as configured, and that attempts to exploit the vulnerability are unsuccessful.

• Post-fix check: Attempt to access http://target/result.php?pc=whoami. The server should return a 403 Forbidden error (or equivalent).
• Re-test: Re-run the earlier detection method – accessing result.php with a malicious payload – and confirm it no longer works.
• Monitoring: Monitor web server logs for access attempts to result.php. An increase in blocked requests could indicate ongoing probing.

# Expected output after blocking access: 403 Forbidden

6. Preventive Measures and Monitoring

Regular security assessments and a robust patch management process are essential for preventing similar vulnerabilities.

• Baselines: Update your web server baseline configuration to include input validation rules and access restrictions.
• Asset and patch process: Implement a regular review cycle for WANem configurations and security updates.

7. Risks, Side Effects, and Roll Back

Disabling or restricting access to result.php may impact certain WANem features that rely on this script.

• Risk or side effect 1: Disabling result.php could break functionality if it’s used by other parts of the application.
• Risk or side effect 2: Restricting access to specific IP addresses may require ongoing maintenance as network configurations change.
• Roll back: Remove the block on result.php in your web server configuration and restart the web server service. Restore the previous WANem configuration if necessary.

8. References and Resources

Links only to sources that match this exact vulnerability. Use official advisories and trusted documentation. Do not include generic links.

• Vendor advisory or bulletin: http://www.nessus.org/u?60995f52
• NVD or CVE entry: Not available in the provided context.
• Product or platform documentation relevant to the fix: WANem documentation regarding web server configuration and access control.