CVE-2025-29135

Remediation/Mitigation Strategy for CVE-2025-29135

This document outlines the remediation and mitigation strategy for CVE-2025-29135, a stack-based buffer overflow vulnerability affecting Tenda AC7 V15.03.06.44.

1. Vulnerability Description

  • CVE ID: CVE-2025-29135
  • Product: Tenda AC7
  • Version: V15.03.06.44
  • Description: A stack-based buffer overflow vulnerability exists in the formWifiBasicSet function of Tenda AC7 V15.03.06.44. A remote attacker can exploit this vulnerability by sending a crafted request with an overly long security parameter, overflowing the stack buffer and potentially executing arbitrary code on the device.

2. Severity

  • CVSS v3 Score: 9.8 (Critical)
    • CVSS v3 Vector: (Based on the provided information, the vector components are:)
      • AV:N (Attack Vector: Network)
      • AC:L (Attack Complexity: Low)
      • PR:N (Privileges Required: None)
      • UI:N (User Interaction: None)
      • S:U (Scope: Unchanged)
      • C:H (Confidentiality: High)
      • I:H (Integrity: High)
      • A:H (Availability: High)
  • Severity Level: Critical
  • Explanation: The vulnerability is remotely exploitable without authentication (AV:N, PR:N), requires low attack complexity (AC:L), and can lead to complete compromise of the affected device (C:H, I:H, A:H), including potential code execution.

3. Known Exploits

  • The provided information indicates that a known exploit exists, although the specific details are not included. Based on the vulnerability description, the exploit likely involves sending a specially crafted HTTP request to the router’s web interface with an oversized security parameter within the formWifiBasicSet function’s context.

4. Remediation Strategy

  • Priority: Immediate. Given the critical severity and the presence of a known exploit, remediation should be implemented as soon as possible.

  • Steps:

    1. Upgrade Firmware: The primary remediation step is to upgrade to a patched firmware version provided by Tenda. Check the Tenda support website (www.tenda.com.cn) for the latest firmware updates for your AC7 model. Applying the update will overwrite the vulnerable code with a corrected version. This should be the preferred approach.
    2. Disable Remote Access: If a firmware patch is not immediately available, disable remote access to the Tenda AC7’s web interface from the internet. This can be done through the router’s administrative interface. Restricting access to the local network significantly reduces the attack surface. Navigate to the “Administration” or “Remote Management” section and disable any options allowing access from the WAN (Wide Area Network) or Internet.
    3. Access Control Lists (ACLs): If remote access is necessary, implement strict ACLs to restrict access to the router’s web interface to only trusted IP addresses. This can be configured in the router’s firewall settings.
    4. Input Validation Review (For Tenda Developers): For Tenda developers, a thorough review of the formWifiBasicSet function, specifically the handling of the security parameter, is necessary. Implement proper input validation to ensure that the length of the security parameter does not exceed the buffer size. Use safe string handling functions (e.g., strncpy instead of strcpy) to prevent buffer overflows. Consider using static code analysis tools to identify other potential vulnerabilities.

5. Mitigation Strategy (Interim Measures)

  • Network Segmentation: Segment the network to isolate the Tenda AC7 router from critical assets. This limits the potential impact of a successful exploit.

  • Intrusion Detection/Prevention Systems (IDS/IPS): Implement or configure IDS/IPS to detect and block malicious traffic targeting the formWifiBasicSet function. Create custom rules based on the known exploit patterns.

  • Log Monitoring: Enable logging on the Tenda AC7 and monitor the logs for suspicious activity, such as failed login attempts or unusual requests to the web interface.

  • User Awareness: Educate users about the potential risks associated with compromised routers and the importance of strong passwords and secure network practices.

6. Verification

  • After applying the firmware update or implementing any mitigation measures, verify that the vulnerability has been successfully addressed.
    • Testing: Attempt to exploit the vulnerability using the known exploit (if available) or by crafting a similar malicious request.
    • Review Configuration: Double-check the router’s configuration to ensure that remote access is disabled or restricted, ACLs are properly configured, and logging is enabled.
    • Vulnerability Scanning: Run a vulnerability scan on the router to confirm that CVE-2025-29135 is no longer detected.

7. Long-Term Recommendations

  • Secure Development Practices: Tenda should implement secure development practices to prevent similar vulnerabilities in future products. This includes:

    • Regular security audits
    • Static and dynamic code analysis
    • Input validation and sanitization
    • Secure coding training for developers
    • Vulnerability disclosure program

  • Firmware Update Process: Improve the firmware update process to make it easier for users to apply updates. Consider implementing automatic firmware updates.

This remediation/mitigation strategy should be implemented in a timely manner to protect against potential exploitation of CVE-2025-29135. Continuously monitor for new information and adjust the strategy as needed.

Assigner

Date

  • Published Date: 2025-03-24 21:15:18
  • Updated Date: 2025-03-26 15:16:20

More Details

CVE-2025-29135