CVE-2021-39509 : Exploit Details and Defense Strategies

This CVE entry pertains to a vulnerability found in D-Link DIR-816A2_FWv1.10CNB05_R1B011D88210 that allows command injection through shell metacharacters.

Understanding CVE-2021-39509

This section provides insights into the nature of the vulnerability.

What is CVE-2021-39509?

CVE-2021-39509 is a security flaw in D-Link DIR-816A2_FWv1.10CNB05_R1B011D88210, where the HTTP request parameter can be exploited to execute commands via shell metacharacters.

The Impact of CVE-2021-39509

The vulnerability can lead to an attacker injecting malicious commands, potentially compromising the affected system's security.

Technical Details of CVE-2021-39509

Detailed technical information about the CVE is given below.

Vulnerability Description

The issue lies in the handler function of the /goform/form2userconfig.cgi route, allowing construction of a user name string to delete user function, enabling command injection.

Affected Systems and Versions

Product: D-Link DIR-816
Version: DIR-816A2_FWv1.10CNB05_R1B011D88210

Exploitation Mechanism

The HTTP request parameter is mishandled in the mentioned route, leading to the execution of arbitrary commands through shell metacharacters.

Mitigation and Prevention

Preventive measures and steps to mitigate the vulnerability are outlined below.

Immediate Steps to Take

Apply the latest security patches provided by D-Link to address the vulnerability.
Restrict network access to only trusted entities to minimize the attack surface.

Long-Term Security Practices

Regularly update and patch all network devices and systems to mitigate potential risks.
Conduct security audits and assessments to identify and address any underlying security issues.

Patching and Updates

Ensure timely installation of security updates and patches released by D-Link to remediate the vulnerability.