CVE-2022-20934: Vulnerability in Cisco Firepower Threat Defense and Cisco FXOS Software CLI

A recently discovered vulnerability, assigned CVE-2022-20934, has been identified in the Command Line Interface (CLI) of Cisco Firepower Threat Defense (FTD) Software and Cisco FXOS Software that could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system. This vulnerability is a result of improper input validation for specific CLI commands which could lead to potential security breaches and unauthorized access.

Original References

- Cisco Security Advisory: Cisco Firepower Threat Defense Software and Cisco FXOS Software Command Injection Vulnerability
- CVE-2022-20934 - National Vulnerability Database

Exploit Details

The vulnerability occurs because the software does not properly validate input for certain CLI commands. An attacker could exploit this vulnerability by injecting operating system commands into a legitimate command. A successful exploit could allow the attacker to escape the restricted command prompt and execute arbitrary commands on the underlying operating system, potentially compromising the entire system.

As an example, let's assume the following vulnerable CLI command

$ cli_command --option "Option; injected_command"

An attacker with Administrator credentials could inject an arbitrary command within the legitimate command to be executed on the underlying operating system as follows:

$ cli_command --option "Option; rm -rf /tmp"

This would result in the original command running with the specified option and also removing all files within the /tmp directory, essentially granting the attacker the ability to execute arbitrary commands with escalated root privileges.

Requirements

To successfully exploit this vulnerability, an attacker would need valid Administrator credentials.

Mitigation and Solutions

Cisco has released a software update to address this vulnerability. Administrators are advised to apply the necessary update as soon as possible. In addition, administrators should perform the following actions to mitigate the risk:

1. Restrict network access to the management interface and ensure that only authorized, trusted users have access to administrator credentials.
2. Monitor and audit the use of CLI commands and access to the underlying operating system for any suspicious activities.
3. Enable security monitoring tools and intrusion prevention systems to detect and prevent unauthorized access to internal networks.

As a temporary solution, administrators can disable CLI access for the affected software until the patch is applied. This will help prevent potential unauthorized access and command execution.

Conclusion

CVE-2022-20934 is a significant vulnerability that could allow an attacker to execute arbitrary commands as root, potentially leading to further compromise of the affected system. It is essential to apply the necessary software update and follow the recommended mitigation strategies to ensure the security of your Cisco FTD and FXOS devices. Stay vigilant and stay protected.

Timeline

Published on: 11/15/2022 21:15:00 UTC
Last modified on: 11/29/2022 14:13:00 UTC