CVE-2021-46394 : Exploit Details and Defense Strategies

A stack buffer overflow vulnerability in the formSetPPTPServer function of Tenda-AX3 router V16.03.12.10_CN allows remote code execution.

Understanding CVE-2021-46394

This CVE describes a critical security issue in the Tenda-AX3 router that can be exploited for remote code execution.

What is CVE-2021-46394?

The vulnerability arises from a stack buffer overflow in the formSetPPTPServer function of the Tenda-AX3 router, version V16.03.12.10_CN. Attackers can leverage this flaw to craft malicious data leading to remote code execution.

The Impact of CVE-2021-46394

The vulnerability permits attackers to achieve remote code execution on affected Tenda-AX3 routers, posing a severe security threat to users and their data.

Technical Details of CVE-2021-46394

This section provides technical insights into the vulnerability.

Vulnerability Description

The vulnerability stems from the lack of security checks in handling the http request parameter startIp, leading to a stack buffer overflow via the sscanf function.

Affected Systems and Versions

Product: Tenda-AX3 router
Version: V16.03.12.10_CN

Exploitation Mechanism

By POSTing to /goform/SetPptpServerCfg with a carefully crafted startIp parameter, attackers can trigger the stack buffer overflow allowing them to execute arbitrary remote code.

Mitigation and Prevention

Protect your systems from CVE-2021-46394 with these proactive measures.

Immediate Steps to Take

Apply security patches provided by the router vendor promptly.
Restrict network access to vulnerable devices.
Employ network monitoring to detect any unusual activity.

Long-Term Security Practices

Regularly update firmware and software to address security vulnerabilities.
Conduct security audits and penetration testing to identify weaknesses.

Patching and Updates

Ensure timely installation of patches released by Tenda to mitigate the CVE-2021-46394 vulnerability.