How to remediate – AOST Network Video Recorder Detection

1. Introduction

The AOST Network Video Recorder Detection vulnerability refers to the presence of a web interface for an AOST network video recorder on a remote host. This indicates a potentially unmanaged device is connected to your network, which could be exploited by attackers. This affects systems running network video recorders manufactured by AOST or repackaged with different branding. A successful exploit could lead to information disclosure and potential remote control of the device, impacting confidentiality, integrity, and availability.

2. Technical Explanation

Nessus detected a web interface associated with an AOST network video recorder. These devices often have default or weak credentials, making them susceptible to unauthorized access. An attacker could exploit this by gaining access to the device’s web interface and potentially executing commands or modifying its configuration. There is no known CVE currently associated with this detection but it represents a high risk due to common misconfigurations.

• Root cause: The presence of an unmanaged network video recorder on the network, often with default credentials or outdated firmware.
• Exploit mechanism: An attacker could attempt to access the web interface using default credentials (often ‘admin’/’admin’) and then leverage any vulnerabilities present in the device’s software.
• Scope: Network video recorders manufactured by AOST, or devices repackaged with different branding but based on AOST firmware.

3. Detection and Assessment

Confirming whether a system is vulnerable involves identifying the presence of the web interface and checking its configuration.

• Quick checks: Use `nmap -p 80,443 ` to check if ports 80 or 443 are open. Access the device’s web interface in a browser to confirm it is an AOST NVR.
• Scanning: Nessus plugin ID 16729 can detect this vulnerability. Other vulnerability scanners may also have similar plugins.
• Logs and evidence: Check firewall logs for connections to ports 80 or 443 originating from the target IP address.

nmap -p 80,443 

4. Solution / Remediation Steps

Fixing this issue requires identifying and securing or removing the vulnerable device.

4.1 Preparation

• Ensure you have access to the NVR’s web interface for configuration changes. A roll back plan involves restoring the snapshot or re-imaging the device.
• A change window may be required depending on the impact of stopping related services. Approval from the system owner is recommended.

4.2 Implementation

1. Step 1: Access the NVR’s web interface using a web browser.
2. Step 2: Change the default username and password to strong, unique credentials.
3. Step 3: Update the firmware to the latest version available from AOST’s website (http://www.aost.cn/).
4. Step 4: Disable any unnecessary services or features on the NVR.

4.3 Config or Code Example

Before

Default username: admin
Default password: admin

After

Username: 
Password: 

4.4 Security Practices Relevant to This Vulnerability

List only practices that directly address this vulnerability type. Use neutral wording and examples instead of fixed advice. For example: least privilege, input validation, safe defaults, secure headers, patch cadence.

• Practice 1: Strong password policies enforce the use of complex credentials to prevent brute-force attacks.
• Practice 2: Regular patching ensures that known vulnerabilities are addressed promptly.

4.5 Automation (Optional)

# Example PowerShell script to check for default credentials (requires access to NVR web API):
# $url = "http:///api/credentials"
# $response = Invoke-WebRequest -Uri $url -UseBasicAuth -Credential (Get-Credential)
# if ($response.Content -match "admin") { Write-Host "Default credentials found!" }

5. Verification / Validation

Confirm the fix worked by verifying the new credentials and checking for updated firmware.

• Post-fix check: Attempt to log in to the NVR’s web interface using the default username and password – access should be denied.
• Re-test: Run Nessus plugin ID 16729 again; it should no longer report the vulnerability.
• Smoke test: Verify that video recording and playback functionality are still working as expected.
• Monitoring: Monitor firewall logs for failed login attempts to detect potential brute-force attacks.

Attempt to log in with admin/admin - should fail

6. Preventive Measures and Monitoring

Suggest only measures that are relevant to the vulnerability type. Use “for example” to keep advice conditional, not prescriptive.

• Baselines: Update your network device baseline to include requirements for strong passwords and regular firmware updates.
• Pipelines: Implement automated scanning in your CI/CD pipeline to detect unmanaged devices on the network.
• Asset and patch process: Establish a regular schedule for reviewing and patching all network devices, including NVRs.

7. Risks, Side Effects, and Roll Back

• Risk or side effect 1: Incorrect firmware updates could brick the device; download firmware from official sources only.
• Risk or side effect 2: Changing credentials may disrupt existing integrations; document all changes carefully.

8. References and Resources

• Vendor advisory or bulletin: http://www.aost.cn/