How to remediate – Airport Administrative Traffic Detection (192/UDP)

1. Introduction

Airport Administrative Traffic Detection (192/UDP) is a vulnerability affecting Apple Airport wireless access points. It allows attackers on the same network to gather information about the base station and potentially cause denial of service by disconnecting users using PPPoE. This impacts confidentiality through information disclosure, integrity if an attacker manipulates connection details, and availability due to potential disconnections.

2. Technical Explanation

The Airport access point listens for UDP packets on port 192, allowing information gathering about its configuration. An attacker can send crafted packets to this port to retrieve details like the connection type and time. If the base station uses PPPoE, an attacker may be able to force a disconnection. There is no known CVE associated with this vulnerability.

• Root cause: The Airport access point unnecessarily exposes administrative information via UDP port 192 without proper authentication or authorization.
• Exploit mechanism: An attacker sends UDP packets to the remote host on port 192 and analyzes the response for configuration details. They can then attempt to disconnect users by sending malicious packets if PPPoE is used.
• Scope: Apple Airport, Airport Extreme, and Airport Express wireless access points are affected.

3. Detection and Assessment

You can confirm vulnerability by checking for open port 192 on the Airport base station. A thorough method involves network traffic analysis to identify packets being sent to this port.

• Quick checks: Use `netstat -an | grep .192` on a system connected to the wireless network. This will show if anything is listening on that port.
• Scanning: Nmap can be used with the following command as an example: nmap -p 192 .
• Logs and evidence: Check firewall logs for incoming traffic to UDP port 192.

netstat -an | grep .192

4. Solution / Remediation Steps

Filter incoming traffic to UDP port 192 on the Airport base station and restrict network access to authorized hosts only.

4.1 Preparation

• Dependencies: Access to the Airport base station’s firewall settings. Change window needs depend on network size and impact; approval from a network administrator may be needed.

4.2 Implementation

1. Step 1: Log in to your Airport base station’s web interface.
2. Step 2: Navigate to the Firewall settings.
3. Step 3: Add a rule to block incoming traffic on UDP port 192 from all sources except authorized hosts.
4. Step 4: Save the changes and reboot the Airport base station if prompted.

4.3 Config or Code Example

Before

# No specific rule for UDP port 192 - traffic is allowed by default

After

# Block incoming UDP port 192 from all sources except authorized hosts.  Example: Allow only 192.168.1.100 to connect on UDP 192.
Firewall Rule: Deny Incoming UDP Port 192, Source: Any, Destination: Airport IP Address
Firewall Rule: Allow Incoming UDP Port 192, Source: 192.168.1.100, Destination: Airport IP Address

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: Network segmentation can limit the impact of an attacker gaining access to the wireless network.
• Practice 2: Least privilege principles should be applied by only allowing authorized hosts to connect to sensitive services on the Airport base station.

4.5 Automation (Optional)

# No automation available for this vulnerability due to limited scripting capabilities on Airport devices.

5. Verification / Validation

Confirm the fix by checking that UDP port 192 is no longer accessible from unauthorized hosts. Re-run the earlier detection method to verify the issue is resolved.

• Post-fix check: Run `netstat -an | grep .192` again; it should not show any listening processes on port 192 unless authorized access is configured.
• Re-test: Re-run the Nmap scan from earlier; it should report that UDP port 192 is closed.
• Smoke test: Verify that wireless clients can still connect to the network and access internet resources.
• Monitoring: Monitor firewall logs for any attempts to connect to UDP port 192, indicating potential malicious activity.

netstat -an | grep .192

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 security baseline or policy to include a rule blocking unnecessary incoming traffic on UDP port 192 for all Airport devices.
• Pipelines: Implement regular network scans to identify open ports and potential vulnerabilities.
• Asset and patch process: Maintain an inventory of all Apple Airport devices and ensure they are running the latest firmware updates.

7. Risks, Side Effects, and Roll Back

• Risk or side effect 2: Potential service disruption during reboot if required. Mitigation: Schedule changes during off-peak hours.
• Roll back: Remove the firewall rule blocking UDP port 192 and restore the previous Airport configuration from backup.

8. References and Resources

• Vendor advisory or bulletin: Apple support document on Airport security
• NVD or CVE entry: Not applicable, as there is no associated CVE.
• Product or platform documentation relevant to the fix: Apple Airport Base Station User Guide