CVE-2023-43847

Executive Summary

CVE-2023-43847 is a critical access control vulnerability in the Aten PE6208 Power Distribution Unit (PDU). The flaw resides in the outlet control function of the web interface, allowing any authenticated user to control all outlets as if they were an administrator. This is achieved by sending crafted HTTP POST requests that bypass role-based access controls. The vulnerability affects firmware versions 2.3.228 and 2.4.232. No official patch has been released by Aten, and the vendor’s status remains unknown. The EPSS score is 0.0%, indicating low exploitation probability in the wild, but the risk is high for organizations using this device in critical infrastructure.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a hardware firmware issue in the Aten PE6208 PDU.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (No official CVSS vector assigned)
• Threat Level: High (based on impact and ease of exploitation)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (authenticated user)
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: High (can control all outlets)
• Availability Impact: High (can power cycle critical equipment)

Deep Dive & Mechanics

The vulnerability is due to improper access control in the web interface’s outlet control functionality. The application fails to verify that the authenticated user has administrative privileges before processing outlet control commands. By sending HTTP POST requests to the outlet control endpoint, any authenticated user can toggle, turn on, or turn off any outlet on the device.

The web interface likely uses a session-based authentication mechanism but does not enforce role-based checks on the server side for the outlet control API. This allows a low-privileged user to escalate their privileges to effectively become an administrator for outlet management.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

# Example of vulnerable server-side logic
@app.route('/outlet/control', methods=['POST'])
def control_outlet():
    user = get_current_user()
    if user.is_authenticated:
        outlet_id = request.form['outlet_id']
        action = request.form['action']
        # No admin check
        execute_outlet_action(outlet_id, action)
        return 'OK'
    else:
        return 'Unauthorized', 401

Patched Code (Conceptual):

@app.route('/outlet/control', methods=['POST'])
def control_outlet():
    user = get_current_user()
    if user.is_authenticated and user.is_admin:
        outlet_id = request.form['outlet_id']
        action = request.form['action']
        execute_outlet_action(outlet_id, action)
        return 'OK'
    else:
        return 'Forbidden', 403

Exploitation & Lab Setup

Red Team

Prerequisites:

• Access to an Aten PE6208 with firmware 2.3.228 or 2.4.232
• Valid low-privileged user credentials (e.g., user:password)

Exploitation Steps:

1. Authenticate to the web interface as a low-privileged user.
2. Capture the session cookie (e.g., session=abc123).
3. Send a crafted HTTP POST request to control an outlet:

curl -X POST http://<target_ip>/cgi-bin/outlet_control.cgi \
  -H "Cookie: session=abc123" \
  -d "outlet=1&action=on"

4. Repeat for other outlets or actions (off, reboot).

Expected Outcome: The outlet toggles despite the user not being an administrator.

Blue Team

Detection:

• Monitor for HTTP POST requests to /cgi-bin/outlet_control.cgi from non-admin users.
• Correlate with session logs to identify privilege escalation attempts.
• Alert on multiple outlet control actions in a short time frame.

Hunting:

• Search web server logs for outlet_control.cgi with POST method.
• Look for unusual patterns like controlling many outlets sequentially.

Indicators of Compromise (IOCs)

• Network: HTTP POST requests to /cgi-bin/outlet_control.cgi with parameters outlet and action.
• Logs: Web server logs showing non-admin users accessing outlet control endpoints.
• Behavior: Unexpected power cycling of equipment connected to the PDU.

Detection Engineering

YARA Rule

rule CVE_2023_43847_Outlet_Control {
    meta:
        description = "Detects HTTP POST requests targeting Aten PE6208 outlet control"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-43847"
    strings:
        $s1 = "outlet_control.cgi" ascii wide nocase
        $s2 = "outlet=" ascii wide nocase
        $s3 = "action=" ascii wide nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2023-43847 - Aten PE6208 Outlet Control Bypass
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP POST requests to outlet control endpoint by non-admin users
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/cgi-bin/outlet_control.cgi'
    condition: selection
falsepositives:
    - Legitimate admin actions
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2023-43847 - Aten PE6208 Outlet Control Bypass";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/cgi-bin/outlet_control.cgi"; http_uri;
    content:"outlet="; http_client_body;
    content:"action="; http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Restrict network access to the PDU web interface to trusted IPs only.
2. Use a firewall or ACL to limit access to the management interface.
3. Monitor logs for unauthorized outlet control attempts.

Long-term Fix:

• No official patch available. Contact Aten support for updates.
• Consider replacing the device with a patched alternative.
• Implement network segmentation to isolate PDUs from general user networks.

Workaround:

• Disable the web interface if not needed and use SNMP or CLI for management.
• Implement a reverse proxy with authentication to add an extra layer of access control.

Valters IT
Securing Digital Frontiers