EUVD-2025-6520

Comprehensive Technical Analysis of EUVD-2025-6520

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-6520 pertains to a stack overflow in the wanMTU parameter of the /goform/AdvSetMacMtuWan endpoint in Tenda AC9 v1.0 V15.03.05.14_multi. This vulnerability can be exploited to achieve remote arbitrary code execution, which is highly critical.

Severity Evaluation:

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

The CVSS vector indicates:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): None (N)
• User Interaction (UI): None (N)
• Scope (S): Unchanged (U)
• Confidentiality (C): High (H)
• Integrity (I): High (H)
• Availability (A): High (H)

This high severity score underscores the critical nature of the vulnerability, which can be exploited remotely without any user interaction or special privileges.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: An attacker can send specially crafted packets to the vulnerable endpoint, leading to a stack overflow.
• Network-Based Attacks: Given the network attack vector, this vulnerability can be exploited over the internet, making it a prime target for remote attackers.

Exploitation Methods:

• Buffer Overflow: By sending a large payload to the wanMTU parameter, an attacker can overwrite the stack, leading to arbitrary code execution.
• Code Injection: Once the stack is overwritten, the attacker can inject malicious code to gain control over the device.

3. Affected Systems and Software Versions

Affected Systems:

• Tenda AC9 v1.0 V15.03.05.14_multi

Software Versions:

• Firmware version V15.03.05.14_multi

It is crucial to identify and update all devices running this specific firmware version to mitigate the risk.

4. Recommended Mitigation Strategies

Immediate Actions:

• Firmware Update: Apply the latest firmware update provided by Tenda. Ensure that all devices are updated to a version that addresses this vulnerability.
• Network Segmentation: Isolate vulnerable devices from critical networks to limit the potential impact of an exploit.
• Firewall Rules: Implement strict firewall rules to block unauthorized access to the /goform/AdvSetMacMtuWan endpoint.

Long-Term Strategies:

• Regular Patch Management: Establish a routine for regularly updating firmware and software to protect against known vulnerabilities.
• Intrusion Detection Systems (IDS): Deploy IDS to monitor network traffic for suspicious activities that may indicate an exploitation attempt.
• Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate potential risks.

5. Impact on European Cybersecurity Landscape

The vulnerability in Tenda AC9 devices poses a significant risk to the European cybersecurity landscape, particularly in environments where these devices are widely deployed. The potential for remote arbitrary code execution can lead to:

• Data Breaches: Unauthorized access to sensitive information.
• Network Compromise: Attackers gaining control over network infrastructure.
• Service Disruption: Denial of service attacks affecting availability.

Given the critical nature of the vulnerability, it is essential for organizations to prioritize mitigation efforts to protect against potential exploits.

6. Technical Details for Security Professionals

Vulnerability Details:

• Endpoint: /goform/AdvSetMacMtuWan
• Parameter: wanMTU
• Vulnerability Type: Stack Overflow

Exploitation Steps:

1. Identify Target: Scan the network for devices running Tenda AC9 v1.0 V15.03.05.14_multi.
2. Craft Payload: Create a payload that exceeds the buffer size for the wanMTU parameter.
3. Send Request: Send the crafted payload to the vulnerable endpoint.
4. Execute Code: Overwrite the stack and inject malicious code to gain control.

Detection and Monitoring:

• Log Analysis: Monitor logs for unusual activity related to the /goform/AdvSetMacMtuWan endpoint.
• Anomaly Detection: Use anomaly detection tools to identify abnormal traffic patterns that may indicate an exploitation attempt.

References:

• NVD Entry
• GitHub Repository

By following these recommendations and staying vigilant, organizations can effectively mitigate the risks associated with EUVD-2025-6520 and enhance their overall cybersecurity posture.