CVE-2020-13389 : Exploit Details and Defense Strategies

An issue was discovered on Tenda AC6 V1.0 V15.03.05.19_multi_TD01, AC9 V1.0 V15.03.05.19(6318)CN, AC9 V3.0 V15.03.06.42_multi, AC15 V1.0 V15.03.05.19_multi_TD01, and AC18 V15.03.05.19(6318)_CN devices. There is a buffer overflow vulnerability in the router's web server -- httpd. An attacker can exploit this vulnerability to execute arbitrary code.

Understanding CVE-2020-13389

This CVE identifies a buffer overflow vulnerability in Tenda routers that can be exploited by attackers to execute arbitrary code.

What is CVE-2020-13389?

The vulnerability exists in the router's web server, specifically in the httpd component, allowing attackers to overwrite the return address of a function by manipulating certain parameters in a POST request.

The Impact of CVE-2020-13389

Exploitation of this vulnerability can lead to arbitrary code execution attacks, giving attackers unauthorized access and control over the affected devices.

Technical Details of CVE-2020-13389

This section provides more in-depth technical insights into the vulnerability.

Vulnerability Description

The vulnerability arises from a buffer overflow in the router's web server, httpd, during the processing of specific parameters in a POST request. This allows attackers to overwrite the return address of a function, enabling them to execute arbitrary code.

Affected Systems and Versions

Tenda AC6 V1.0 V15.03.05.19_multi_TD01
Tenda AC9 V1.0 V15.03.05.19(6318)_CN
Tenda AC9 V3.0 V15.03.06.42_multi
Tenda AC15 V1.0 V15.03.05.19_multi_TD01
Tenda AC18 V15.03.05.19(6318_)_CN

Exploitation Mechanism

By crafting a malicious payload and sending it through the /goform/openSchedWifi schedStartTime and schedEndTime parameters in a POST request, attackers can trigger the buffer overflow and execute arbitrary code.

Mitigation and Prevention

Protecting systems from CVE-2020-13389 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply security patches provided by Tenda promptly.
Implement network segmentation to limit the impact of potential attacks.
Monitor network traffic for any suspicious activities.

Long-Term Security Practices

Regularly update firmware and software to patch known vulnerabilities.
Conduct security assessments and penetration testing to identify and address weaknesses.
Educate users and administrators about cybersecurity best practices.
Use intrusion detection and prevention systems to enhance network security.
Employ strong access controls and authentication mechanisms.

Patching and Updates

Tenda may release patches to address the vulnerability. It is crucial to apply these patches as soon as they are available to mitigate the risk of exploitation.