How to remediate – Ethernet Card Manufacturer Detection

Contents

1. Introduction

2. Technical Explanation

Each Ethernet MAC address contains a 24-bit Organizationally Unique Identifier (OUI) registered by IEEE. Attackers can use this OUI to identify the card manufacturer. There are no specific preconditions needed for exploitation; simply having an ethernet card is enough. An attacker could scan a network and identify all devices made by a particular vendor, potentially revealing sensitive information about your infrastructure.

Root cause: The Ethernet MAC address includes a publicly registered OUI that reveals the manufacturer.
Exploit mechanism: An attacker scans the network for MAC addresses and uses online databases to identify the corresponding manufacturers.
Scope: All systems with ethernet cards are affected, regardless of platform or version.

3. Detection and Assessment

You can confirm whether a system is vulnerable by identifying the OUI of its Ethernet card. A quick check involves examining network interface details. More thorough methods involve using network scanning tools.

Quick checks: Use the ipconfig /all command on Windows to view MAC addresses and identify the first three octets (the OUI).
Scanning: Nessus plugin ID 794673b4 can be used to detect Ethernet card manufacturers. This is an example only.
Logs and evidence: Network traffic captures will show MAC addresses, which can be analyzed for OUIs.

ipconfig /all

4. Solution / Remediation Steps

There is no direct fix for this vulnerability as it’s inherent to how Ethernet cards are manufactured and identified. The focus should be on understanding the information disclosure risk and implementing appropriate security practices.

4.1 Preparation

No backups or service stops are needed.
There are no dependencies or pre-requisites. A roll back plan is not applicable as there’s no change to implement.
Change windows and approvals are not required.

4.2 Implementation

Step 1: Document the potential information disclosure risk associated with identifying Ethernet card manufacturers on your network.
Step 2: Review security practices related to network segmentation and access control.

4.3 Config or Code Example

No configuration changes are needed.

Before

N/A

After

N/A

4.4 Security Practices Relevant to This Vulnerability

Network segmentation can limit the impact of information disclosure. Least privilege access controls prevent unauthorized network scanning and data collection. Patch cadence ensures systems are up-to-date with security fixes, reducing overall attack surface.

Practice 1: Network segmentation reduces the scope of potential attacks if an attacker identifies card manufacturers.
Practice 2: Least privilege access controls limit who can scan the network and collect MAC address information.

4.5 Automation (Optional)

No automation is applicable.

N/A

5. Verification / Validation

Post-fix check: Confirm documentation exists outlining the information disclosure risk.
Re-test: Not applicable.
Monitoring: Monitor network logs for unusual scanning activity or unauthorized access attempts. This is an example only.

N/A

6. Preventive Measures and Monitoring

Regular security assessments can identify potential information disclosure risks. Implementing a robust patch management process ensures systems are up-to-date with the latest security fixes, reducing overall attack surface. Asset inventory helps track hardware and software configurations.

Baselines: Update security baselines to include documentation of information disclosure risks.
Pipelines: Integrate vulnerability scanning into CI/CD pipelines to identify potential issues early in the development lifecycle.
Asset and patch process: Implement a regular asset inventory review cycle to track hardware configurations.

7. Risks, Side Effects, and Roll Back

There are no known risks or side effects associated with documenting this vulnerability and implementing security practices. There is no roll back procedure as there’s no change to revert.

Risk or side effect 1: None.
Risk or side effect 2: None.
Roll back: Not applicable.

8. References and Resources

Official IEEE documentation provides information about OUIs and MAC address registration.

Vendor advisory or bulletin: N/A
NVD or CVE entry: N/A
Product or platform documentation relevant to the fix: https://standards.ieee.org/faqs/regauth.html

Updated on December 27, 2025

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