CVE-2021-20040 : What You Need to Know

A relative path traversal vulnerability in the SonicWall SMA100 upload function enables a remote unauthenticated attacker to upload malicious web pages or files as a 'nobody' user. This vulnerability impacts SMA 200, 210, 400, 410, and 500v appliances.

Understanding CVE-2021-20040

This section delves into the details of the CVE-2021-20040 vulnerability.

What is CVE-2021-20040?

The CVE-2021-20040 is a relative path traversal vulnerability in the SonicWall SMA100 appliance that allows attackers to upload malicious content as a 'nobody' user.

The Impact of CVE-2021-20040

The vulnerability poses a serious risk as remote unauthenticated attackers can exploit it to upload malicious web pages or files on affected appliances.

Technical Details of CVE-2021-20040

This section explores the technical aspects of CVE-2021-20040.

Vulnerability Description

The vulnerability arises due to improper input validation in the upload function of the SMA100 appliance.

Affected Systems and Versions

SonicWall SMA100 versions 10.2.0.8-37sv and earlier, 10.2.1.1-19sv and earlier, and 10.2.1.2-24sv and earlier are affected by this vulnerability.

Exploitation Mechanism

Remote unauthenticated attackers can exploit this vulnerability by uploading crafted web pages or files as a 'nobody' user on the affected SMA appliances.

Mitigation and Prevention

In this section, we discuss the steps to mitigate and prevent exploitation of CVE-2021-20040.

Immediate Steps to Take

Users should apply security patches provided by SonicWall to remediate the vulnerability. Access controls should also be reviewed and tightened.

Long-Term Security Practices

Implementing secure coding practices, conducting regular security audits, and keeping systems up to date with the latest patches are essential for long-term security.

Patching and Updates

Regularly update the SonicWall SMA100 appliances to the latest firmware versions to ensure protection against known vulnerabilities.