EUVD-2023-35884

Comprehensive Technical Analysis of EUVD-2023-35884

1. Vulnerability Assessment and Severity Evaluation

The vulnerability EUVD-2023-35884 affects the Tenda AC5 router, specifically version V15.03.06.28. It is classified as a remote code execution (RCE) vulnerability, which allows an attacker to execute arbitrary code on the affected device. The CVSS (Common Vulnerability Scoring System) base score of 9.8 indicates a critical severity level. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H breaks down as follows:

• AV:N (Attack Vector: Network): The vulnerability is exploitable remotely over the network.
• AC:L (Attack Complexity: Low): The attack requires low complexity to exploit.
• PR:N (Privileges Required: None): No privileges are required to exploit the vulnerability.
• UI:N (User Interaction: None): No user interaction is required.
• S:U (Scope: Unchanged): The vulnerability does not change the security scope.
• C:H (Confidentiality: High): The vulnerability has a high impact on confidentiality.
• I:H (Integrity: High): The vulnerability has a high impact on integrity.
• A:H (Availability: High): The vulnerability has a high impact on availability.

2. Potential Attack Vectors and Exploitation Methods

The primary attack vector involves exploiting the Mac parameter in the ip/goform/WriteFacMac endpoint. An attacker can send a specially crafted request to this endpoint, which can lead to remote code execution. This can be achieved through:

• Network Scanning: Identifying vulnerable Tenda AC5 routers on the network.
• Crafted HTTP Requests: Sending malicious HTTP requests to the WriteFacMac endpoint with the Mac parameter manipulated to inject and execute arbitrary code.

3. Affected Systems and Software Versions

The vulnerability specifically affects Tenda AC5 routers running firmware version V15.03.06.28. Other versions of the Tenda AC5 router may also be affected, but this has not been confirmed. Users should verify their firmware version and apply updates as necessary.

4. Recommended Mitigation Strategies

To mitigate the risk associated with this vulnerability, the following steps are recommended:

• Firmware Update: Immediately update the router firmware to the latest version provided by Tenda.
• Network Segmentation: Isolate the router from critical network segments to limit potential damage.
• Firewall Rules: Implement strict firewall rules to restrict access to the router's management interface.
• Intrusion Detection Systems (IDS): Deploy IDS to monitor for suspicious activity targeting the WriteFacMac endpoint.
• Regular Audits: Conduct regular security audits and vulnerability assessments to identify and address potential security gaps.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to European organizations and individuals using the Tenda AC5 router. Given the critical nature of the vulnerability, it could be exploited to compromise network security, steal sensitive information, and disrupt services. The widespread use of routers in both home and enterprise environments amplifies the potential impact.

6. Technical Details for Security Professionals

Exploitation Details:

• The vulnerability is triggered by sending a malicious HTTP request to the ip/goform/WriteFacMac endpoint with a crafted Mac parameter.
• The Mac parameter is not properly sanitized, allowing for code injection.

Detection:

• Monitor network traffic for unusual requests to the WriteFacMac endpoint.
• Implement logging and alerting for any unauthorized access attempts to the router's management interface.

Patching:

• Ensure that the router firmware is updated to a version that addresses this vulnerability.
• Regularly check for updates and security patches from Tenda.

References:

• Tenda AC5 Product Page
• Tenda Firmware Download
• GitHub Repository with Vulnerability Details

By following these recommendations and staying vigilant, organizations can significantly reduce the risk posed by this vulnerability.