CVE-2021-24016 Explained : Impact and Mitigation

A detailed overview of CVE-2021-24016, focusing on the vulnerability found in Fortinet FortiManager versions 6.4.3 and below, 6.2.7 and below, that allows attackers to execute arbitrary commands.

Understanding CVE-2021-24016

This section delves into the significance and impact of the CVE-2021-24016 vulnerability in Fortinet FortiManager.

What is CVE-2021-24016?

The CVE-2021-24016 vulnerability involves an improper neutralization of formula elements in a csv file in Fortinet FortiManager. Attackers can exploit this issue in versions 6.4.3 and below, as well as 6.2.7 and below, to execute arbitrary commands when a crafted IPv4 field in a policy name is exported as an Excel file and opened unsafely on the victim's host.

The Impact of CVE-2021-24016

The vulnerability poses a low-severity threat, with a base score of 3.5 according to CVSS v3.1. Attack complexity is high, requiring adjacent network access and high privileges. Although the exploit code maturity is at the proof-of-concept stage, user interaction is required for exploitation. Confidentiality and integrity impacts are low, with no availability impact. However, the scope is changed due to the nature of the attack.

Technical Details of CVE-2021-24016

This section outlines specific technical details of CVE-2021-24016, including the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability arises from the improper handling of formula elements in a CSV file in Fortinet FortiManager, allowing malicious actors to execute unauthorized commands when manipulating the IPv4 field in a policy name.

Affected Systems and Versions

Fortinet FortiManager versions 6.4.3 and below, as well as 6.2.7 and below, are impacted by this vulnerability. Users of these versions are at risk of arbitrary command execution by threat actors.

Exploitation Mechanism

To exploit CVE-2021-24016, attackers craft a malicious IPv4 field in a policy name, export it as an Excel file, and trick a victim into opening the file unsafely on their host.

Mitigation and Prevention

In this section, we discuss steps to mitigate the risks associated with CVE-2021-24016 and ensure long-term security practices.

Immediate Steps to Take

Users of Fortinet FortiManager should apply vendor-supplied patches immediately to address the vulnerability. Exercise caution when handling CSV files exported from FortiManager to prevent unauthorized code execution.

Long-Term Security Practices

Implement strict file handling protocols, conduct regular security awareness training, and stay vigilant against phishing attempts to enhance overall security posture.

Patching and Updates

Stay informed about security updates from Fortinet and ensure timely patching of FortiManager to protect against known vulnerabilities.