CVE-2022-33873: FortiTester OS Command Injection Vulnerability - Exploitation Guide, Mitigations, and Patches

In this long-read post, we will discuss a recent vulnerability discovered in FortiTester, identified as CVE-2022-33873. This vulnerability affects FortiTester versions 2.3. through 3.9.1, 4.. through 4.2., and 7.. through 7.1., and it allows an unauthenticated attacker to execute arbitrary commands in the underlying shell. We will provide code snippets, links to original references, and an explanation of the exploit's details.

Vulnerability Overview

CVE-2022-33873 is a vulnerability classified as an Improper Neutralization of Special Elements Used in an OS Command ('OS Command Injection') CWE-78. It has been identified in the Console login components of FortiTester, a popular network testing and security tool by Fortinet.

An attacker can exploit this vulnerability by injecting malicious OS commands into the FortiTester Console login. Successful exploitation could allow arbitrary command execution in the underlying shell, potentially leading to unauthorized access to sensitive information and system compromise.

Exploit Details

The vulnerability is present in the Console login components of FortiTester, specifically in the handling of user input. Below is a code snippet demonstrating a vulnerable section of code, where user input is directly passed to a shell command without proper sanitization:

import os

def login(username, password):
    os.system(f"fortitester_login {username} {password}")

An attacker can exploit this vulnerability by submitting specially crafted input, such as including shell command separators or additional commands. For example, an attacker might use the following input to inject arbitrary commands:

username: admin;rm -rf /
password: fakepass

This injected input would cause the vulnerable console login component to issue the rm -rf / command in addition to the intended login command, leading to data loss and potential system compromise.

Mitigation

Fortinet has released patches to address this vulnerability in the affected FortiTester versions. Users are advised to update their FortiTester installations to the following patched versions:

FortiTester 7.1.1 or later for 7.. through 7.1.

These updated versions can be found on the Fortinet Support Site.

In addition to applying the patches, FortiTester users should follow best practices for secure coding to prevent similar vulnerabilities from reoccurring. This includes properly sanitizing and validating user input, using secure methods for OS command execution, and keeping software libraries up-to-date.

Conclusion

CVE-2022-33873 is a critical vulnerability in FortiTester Console login components that could allow an unauthenticated attacker to execute arbitrary commands on an affected system. Users should apply the relevant patches and follow best practices to mitigate this vulnerability and protect their systems from potential compromise. By staying vigilant and regularly updating your software, you can help ensure the security of your network and prevent similar vulnerabilities from impacting your infrastructure in the future.

Timeline

Published on: 10/18/2022 15:15:00 UTC
Last modified on: 10/21/2022 13:00:00 UTC