EUVD-2023-38621

Comprehensive Technical Analysis of EUVD-2023-38621

1. Vulnerability Assessment and Severity Evaluation

The vulnerability EUVD-2023-38621, also known as CVE-2023-34566, involves a stack overflow in the Tenda AC10 v4 router firmware version US_AC10V4.0si_V16.03.10.13_cn. The stack overflow occurs via the parameter time at the endpoint /goform/saveParentControlInfo.

Severity Evaluation:

• Base Score: 9.8 (Critical)
• Base Score Version: CVSS 3.1
• Base Score Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

The CVSS score of 9.8 indicates a critical vulnerability. The vector string breaks down as follows:

• AV:N (Attack Vector: Network) - The vulnerability is exploitable 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) - There is a high impact on confidentiality.
• I:H (Integrity: High) - There is a high impact on integrity.
• A:H (Availability: High) - There is a high impact on availability.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: Given the network attack vector (AV:N), an attacker can exploit this vulnerability remotely over the internet.
• Unauthenticated Access: The attack does not require any privileges (PR:N), making it easier for attackers to exploit.

Exploitation Methods:

• Crafted HTTP Requests: An attacker can send specially crafted HTTP requests to the /goform/saveParentControlInfo endpoint with a malicious time parameter to trigger the stack overflow.
• Buffer Overflow: The stack overflow can lead to arbitrary code execution, allowing the attacker to gain control over the device.

3. Affected Systems and Software Versions

Affected Systems:

• Tenda AC10 v4 routers

Affected Software Versions:

• Firmware version US_AC10V4.0si_V16.03.10.13_cn

4. Recommended Mitigation Strategies

Immediate Mitigation:

• Network Segmentation: Isolate affected devices from critical networks to limit potential damage.
• Firewall Rules: Implement strict firewall rules to block unauthorized access to the affected endpoint.
• Firmware Update: Apply any available patches or updates from Tenda as soon as they are released.

Long-Term Mitigation:

• Regular Patching: Ensure that all network devices are regularly updated with the latest firmware.
• Intrusion Detection Systems (IDS): Deploy IDS to monitor for suspicious activity targeting the vulnerable endpoint.
• Security Audits: Conduct regular security audits to identify and mitigate similar vulnerabilities.

5. Impact on European Cybersecurity Landscape

The critical nature of this vulnerability poses a significant risk to European cybersecurity. Given the widespread use of Tenda routers, the potential for large-scale exploitation is high. This vulnerability could be leveraged by threat actors to compromise network security, exfiltrate sensitive data, and disrupt services.

Regulatory Implications:

• GDPR Compliance: Organizations must ensure that they comply with GDPR regulations by protecting personal data from unauthorized access.
• NIS Directive: Critical infrastructure providers must adhere to the Network and Information Systems (NIS) Directive to maintain robust cybersecurity measures.

6. Technical Details for Security Professionals

Vulnerability Details:

• Endpoint: /goform/saveParentControlInfo
• Parameter: time
• Vulnerability Type: Stack Overflow

Exploitation Steps:

1. Identify Target: Use network scanning tools to identify Tenda AC10 v4 routers with the vulnerable firmware version.
2. Craft Payload: Develop a payload that exploits the stack overflow via the time parameter.
3. Send Request: Use tools like curl or custom scripts to send the crafted HTTP request to the vulnerable endpoint.
4. Gain Control: If successful, the attacker can execute arbitrary code on the device.

Detection and Response:

• Log Analysis: Monitor logs for unusual activity targeting the /goform/saveParentControlInfo endpoint.
• Anomaly Detection: Implement anomaly detection systems to identify deviations from normal behavior.
• Incident Response: Have an incident response plan in place to quickly address and mitigate any detected exploitation attempts.

References:

• HackMD Research Notes
• Additional Research Notes

By addressing this vulnerability promptly and implementing robust security measures, organizations can significantly reduce the risk of exploitation and protect their networks from potential cyber threats.