CVE-2026-22613

Executive Summary

CVE-2026-22613 is a security advisory affecting Eaton Network M3 devices. The vulnerability stems from an insecurely implemented server identity check mechanism during firmware upgrades performed via command shell. This flaw allows an attacker positioned on the network to perform a Man-in-the-Middle (MitM) attack, potentially intercepting and modifying firmware upgrade traffic. The CVSS score is 5.7 (Medium), and while no public proof-of-concept or exploit code is available, the risk is elevated due to the critical nature of firmware integrity. The vendor has released a fix in the latest firmware version, available on the Eaton download center.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a firmware-level issue in Eaton Network M3 devices, affecting the supply chain of industrial control systems (ICS) and operational technology (OT) environments.

CVSS Breakdown & Threat Level

• CVSS Score: 5.7 (Medium)
• Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
• Attack Vector (AV): Adjacent Network (A) – attacker must be on the same network segment.
• Attack Complexity (AC): High (H) – requires specific conditions and MitM capability.
• Privileges Required (PR): None (N)
• User Interaction (UI): Required (R) – victim must initiate a firmware upgrade via command shell.
• Scope (S): Unchanged (U)
• Confidentiality (C): High (H) – attacker can read firmware data.
• Integrity (I): High (H) – attacker can modify firmware.
• Availability (A): None (N)

Threat Level: Medium. While the CVSS score is moderate, the potential for firmware compromise in OT environments elevates the risk. An attacker could deploy malicious firmware, leading to device takeover or persistent backdoor.

Deep Dive & Mechanics

The vulnerability lies in the server identity check mechanism for firmware upgrades performed via command shell on Eaton Network M3 devices. When a user initiates a firmware upgrade, the device does not properly validate the identity of the server providing the firmware. This allows an attacker to perform a Man-in-the-Middle attack by intercepting the upgrade traffic and presenting a fake server.

Attack Flow:

1. Precondition: Attacker gains access to the same network segment as the Eaton Network M3 device (e.g., via compromised switch, ARP spoofing, or rogue access point).
2. Trigger: A legitimate administrator initiates a firmware upgrade via command shell.
3. MitM: The attacker intercepts the connection between the device and the legitimate firmware server.
4. Exploitation: The attacker presents a fake server with a malicious firmware image. Due to the lack of proper server identity verification, the device accepts the malicious firmware.
5. Impact: The device is flashed with attacker-controlled firmware, potentially allowing persistent remote access, data exfiltration, or disruption of operations.

Root Cause: The server identity check (likely TLS certificate validation or hostname verification) is either missing or improperly implemented. This is a classic CWE-295 (Improper Certificate Validation) issue.

Vulnerable vs. Patched Code

No specific code snippets are available from public sources. However, the fix likely involves implementing proper TLS certificate validation or hostname verification in the firmware upgrade client.

Vulnerable (Conceptual):

# Insecure: No server identity check
def upgrade_firmware(server_url):
    response = requests.get(server_url + "/firmware.bin")
    # No validation of server certificate
    flash_firmware(response.content)

Patched (Conceptual):

# Secure: Proper certificate validation
def upgrade_firmware(server_url):
    response = requests.get(server_url + "/firmware.bin", verify=True)
    # Verify server identity
    if not verify_server_identity(server_url):
        raise Exception("Server identity check failed")
    flash_firmware(response.content)

Exploitation & Lab Setup

Red Team

Objective: Demonstrate MitM attack on firmware upgrade.

Lab Setup:

• Eaton Network M3 device (vulnerable firmware)
• Attacker machine (Kali Linux) on same network
• Legitimate firmware server (simulated)
• Tools: bettercap, mitmproxy, openssl

Steps:

1. Network Reconnaissance: Identify the Eaton device IP and the firmware server IP.
2. ARP Spoofing: Use bettercap to perform ARP spoofing between the device and the firmware server.

   sudo bettercap -eval "set arp.spoof.targets 192.168.1.100; arp.spoof on"
   

3. Setup MitM Proxy: Use mitmproxy to intercept and modify firmware upgrade traffic.

   mitmproxy --mode transparent --listen-port 8080
   

4. Redirect Traffic: Use iptables to redirect HTTP/HTTPS traffic to the proxy.

   sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 8080
   

5. Serve Malicious Firmware: When the upgrade request is intercepted, serve a modified firmware image.
6. Trigger Upgrade: Initiate firmware upgrade from the Eaton device command shell.
7. Verify Compromise: Confirm the device runs the malicious firmware.

Blue Team

Objective: Detect and prevent MitM attacks on firmware upgrades.

Detection:

• Monitor for ARP spoofing anomalies using arpwatch or network monitoring tools.
• Enable TLS certificate pinning on the Eaton device (if supported).
• Use network segmentation to isolate firmware upgrade traffic.
• Implement integrity checks (e.g., checksums, digital signatures) for firmware images.

Prevention:

• Apply the latest firmware patch from Eaton.
• Use out-of-band management for firmware upgrades.
• Deploy network intrusion detection systems (NIDS) to detect MitM patterns.

Indicators of Compromise (IOCs)

• Network:
  • Unexpected ARP replies (ARP spoofing)
  • TLS certificate mismatches during firmware upgrade
  • Unusual firmware server IP addresses
• Host:
  • Modified firmware version string
  • Unexpected processes or services on the Eaton device
  • Changes in device behavior (e.g., unexpected reboots, network connections)
• File:
  • Firmware image with mismatched checksum or digital signature
  • Presence of unauthorized files in firmware storage

Detection Engineering

YARA Rule

rule CVE_2026_22613_MitM_Firmware {
    meta:
        description = "Detects potential MitM attack on Eaton Network M3 firmware upgrade"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2026-22613"
    strings:
        $s1 = "firmware upgrade" nocase
        $s2 = "server identity" nocase
        $s3 = "certificate" nocase
    condition:
        any of ($s*) and filesize < 10KB
}

Sigma Rule

title: CVE-2026-22613 - MitM Attack on Eaton Firmware Upgrade
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects network anomalies indicative of MitM attack during Eaton Network M3 firmware upgrade
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-22613
logsource:
    category: network_connection
    product: suricata
detection:
    selection:
        event_type: alert
        alert.signature_id: 202622613
    condition: selection
falsepositives:
    - Legitimate firmware upgrades from authorized servers
level: high

Suricata Rule

alert tcp any any -> any 443 (msg:"CVE-2026-22613 - Potential MitM on Eaton Firmware Upgrade"; flow:to_server; content:"firmware"; nocase; content:"upgrade"; nocase; sid:202622613; rev:1;)

Remediation & Mitigation

1. Immediate Action: Update Eaton Network M3 firmware to the latest version available on the Eaton download center.
2. Network Segmentation: Isolate Eaton devices on a dedicated VLAN with strict access controls.
3. TLS Enforcement: Ensure all firmware upgrades use TLS with proper certificate validation.
4. Integrity Checks: Implement digital signatures and checksums for firmware images.
5. Monitoring: Deploy network monitoring to detect ARP spoofing and MitM attempts.
6. User Training: Educate administrators on verifying server identity before initiating upgrades.

Valters IT
Securing Digital Frontiers