1. Introduction
The Apple TV Version Detection vulnerability allowed attackers to obtain version and model information from remote Apple TV devices. This can aid reconnaissance efforts, potentially leading to targeted attacks. Systems affected are typically Apple TV devices connected to a network. A successful exploit could lead to increased risk of further compromise.
2. Technical Explanation
The vulnerability occurs because Nessus was able to retrieve version and model information from the Apple TV via an HTTP request to the ‘/server-info’ resource. An attacker can passively gather this data without authentication. There is no known CVE associated with this specific detection, but it highlights a potential information disclosure risk. An attacker could use this information to identify vulnerable devices for targeted exploitation of other vulnerabilities.
- Root cause: The Apple TV exposes version and model information via an unauthenticated HTTP endpoint.
- Exploit mechanism: An attacker sends an HTTP request to the ‘/server-info’ resource on the target Apple TV device.
- Scope: Apple TV devices are affected.
3. Detection and Assessment
You can confirm whether a system is vulnerable by checking for the presence of the exposed information via HTTP requests. A quick check involves using `curl` to access the server-info endpoint, while thorough assessment requires network scanning tools.
- Quick checks: Use the following command to retrieve version and model information:
curl http://<Apple TV IP Address>/server-info - Scanning: Nessus plugin ID 16784 can detect this vulnerability. Other network scanners may also have similar capabilities.
- Logs and evidence: Examine HTTP access logs for requests to the ‘/server-info’ resource originating from unknown sources.
curl http://<Apple TV IP Address>/server-info4. Solution / Remediation Steps
There is no direct patch available for this specific information disclosure vulnerability. Mitigation focuses on network segmentation and monitoring.
4.1 Preparation
- Backups are not required for these steps. No services need to be stopped.
- Dependencies: Ensure you have access to the Apple TV’s network configuration. Rollback involves restoring any firewall rules or network configurations changed during implementation.
- Change window needs and approvals may be needed if modifying network infrastructure.
4.2 Implementation
- Step 1: Implement network segmentation to isolate Apple TVs from untrusted networks.
- Step 2: Monitor network traffic for unauthorized access attempts targeting the ‘/server-info’ resource.
4.3 Config or Code Example
Before
No specific configuration exists to block this, it relies on network access control.After
Implement firewall rules to restrict access to Apple TVs from untrusted networks. Example: deny inbound HTTP traffic from external sources.4.4 Security Practices Relevant to This Vulnerability
Network segmentation and least privilege are relevant practices for mitigating this vulnerability. Least privilege reduces the impact if exploited, while input validation could prevent unauthorized access.
- Practice 1: Network segmentation limits the blast radius of potential attacks.
- Practice 2: Least privilege restricts network access to authorized users and devices only.
4.5 Automation (Optional)
# Example Ansible playbook snippet to block external access:
- name: Block external HTTP access to Apple TVs
firewalld:
zone: public
rich_rule: 'rule family="ipv4" source address="0.0.0.0/0" destination address="<Apple TV IP Address>" port protocol=tcp port=80 reject'
permanent: true
state: enabled5. Verification / Validation
- Post-fix check: Use
curl http://<Apple TV IP Address>/server-infofrom a remote, untrusted network. Expected output should be connection refused or timeout. - Re-test: Re-run the initial `curl` command to confirm access is blocked.
- Smoke test: Verify that Apple TV functions normally on the trusted network (e.g., streaming video).
- Monitoring: Monitor firewall logs for blocked requests to the ‘/server-info’ resource from untrusted sources.
curl http://<Apple TV IP Address>/server-info6. Preventive Measures and Monitoring
Regular security baselines and network monitoring are key preventive measures. For example, update a security baseline to include firewall rules blocking external access to Apple TVs.
- Baselines: Update your security baseline to include network segmentation policies for all IoT devices.
- Pipelines: Implement CI/CD pipelines with SAST and SCA tools to identify vulnerable components in device firmware.
- Asset and patch process: Establish a regular review cycle for Apple TV configurations and firmware updates.
7. Risks, Side Effects, and Roll Back
Implementing firewall rules may disrupt legitimate network traffic if not configured correctly. Roll back involves removing the newly added firewall rules.
- Risk or side effect 1: Incorrectly configured firewall rules could block legitimate access to Apple TVs.
- Risk or side effect 2: Network connectivity issues may occur if segmentation is too restrictive.
- Roll back: Remove the firewall rule added in Step 2 using the `firewalld` command with the `–permanent=false` option, then reload the firewall configuration.
8. References and Resources
- Vendor advisory or bulletin: https://www.apple.com/tv/
- NVD or CVE entry: No specific CVE is associated with this detection.
- Product or platform documentation relevant to the fix: https://support.apple.com/en-gb/HT201964 (Apple TV security overview)