CVE-2021-27691 Explained : Impact and Mitigation

Command Injection in Tenda G0 routers with specific firmware versions, as well as Tenda G1 and G3 routers, allows remote attackers to execute arbitrary OS commands. This vulnerability arises due to the execution of untrusted input in the "formSetDebugCfg" function.

Understanding CVE-2021-27691

This CVE identifies a critical vulnerability in Tenda routers that can be exploited by malicious actors to run unauthorized commands on affected devices.

What is CVE-2021-27691?

The CVE-2021-27691 involves a command injection flaw in certain Tenda router models. Attackers can leverage this vulnerability to execute malicious code remotely.

The Impact of CVE-2021-27691

The impact of this vulnerability is severe as it allows threat actors to gain unauthorized access to Tenda routers and potentially compromise the entire network.

Technical Details of CVE-2021-27691

This section delves into the specific technical aspects of the CVE, including the vulnerability description, affected systems, versions, and the exploitation mechanism.

Vulnerability Description

The vulnerability stems from the routers' firmware versions, enabling attackers to execute arbitrary OS commands through a crafted request.

Affected Systems and Versions

Tenda G0 routers with firmware versions v15.11.0.6(9039)_CN and v15.11.0.5(5876)_CN, and Tenda G1 and G3 routers with firmware versions v15.11.0.17(9502)_CN or v15.11.0.16(9024)_CN are susceptible to this vulnerability.

Exploitation Mechanism

The flaw allows remote attackers to execute unauthorized commands by exploiting the "formSetDebugCfg" function in the routers' firmware.

Mitigation and Prevention

To safeguard systems from CVE-2021-27691, immediate steps need to be taken and long-term security practices should be implemented along with timely patching and updates.

Immediate Steps to Take

Users should restrict network access to vulnerable Tenda routers, apply security best practices, and monitor for any suspicious activities.

Long-Term Security Practices

Regular security audits, network segmentation, strong password policies, and keeping abreast of security updates are crucial for fortifying network defenses.

Patching and Updates

Ensure that affected Tenda routers are updated with the latest firmware patches and security updates to mitigate the risk of exploitation.