CVE-2024-11611

Executive Summary

CVE-2024-11611 is a critical memory corruption vulnerability in AutomationDirect C-More EA9 HMI (Human-Machine Interface) panels. The flaw resides in the parsing of EAP9 project files, where improper validation of user-supplied data can lead to a memory corruption condition. An attacker can exploit this by convincing a user to open a malicious EAP9 file, leading to remote code execution in the context of the current process. With a CVSS score of 7.8, this vulnerability poses a significant risk to industrial control systems (ICS) environments, potentially allowing attackers to gain a foothold in OT networks. No public proof-of-concept (PoC) or patch is currently available, making detection and mitigation critical.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Base Score: 7.8 (High)
• Attack Vector (AV): Local (L) – Exploitation requires the attacker to have local access or trick the user into opening a file.
• Attack Complexity (AC): Low (L) – No special conditions beyond user interaction.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – The victim must open a malicious file.
• Scope (S): Unchanged (U) – The vulnerability affects only the vulnerable component.
• Confidentiality (C): High (H) – Full data access possible.
• Integrity (I): High (H) – Full data modification possible.
• Availability (A): High (H) – Full system denial of service possible.

Threat Level: High. The vulnerability allows arbitrary code execution in the context of the HMI software, which can lead to full compromise of the engineering workstation and potentially the connected PLCs.

Deep Dive & Mechanics

The vulnerability exists in the EAP9 file parser of AutomationDirect C-More EA9 software. EAP9 files are project files used to configure HMI screens, tags, and logic. The specific flaw is a memory corruption issue caused by insufficient validation of user-supplied data within the file structure.

Technical Details:

• Root Cause: The parser does not properly check the size or boundaries of data read from the EAP9 file. An attacker can craft a file with specially crafted fields that cause the parser to write data beyond allocated buffers.
• Trigger: When a user opens the malicious EAP9 file (e.g., via double-click or drag-and-drop), the parser processes the file and triggers a buffer overflow or similar memory corruption.
• Impact: The corruption can overwrite critical data structures, leading to arbitrary code execution. Since the software runs in user mode, the attacker gains the same privileges as the logged-in user.

Attack Scenario:

1. An attacker crafts a malicious EAP9 file and hosts it on a website or sends it via email.
2. The victim (e.g., an engineer) opens the file using C-More EA9 software.
3. The parser processes the file, triggering memory corruption.
4. The attacker's payload executes, potentially installing backdoors, exfiltrating data, or pivoting to other OT devices.

Vulnerable vs. Patched Code

No patch is currently available. The vulnerable code is in the EAP9 file parser module. A patched version would include proper bounds checking and input validation.

Vulnerable Code (Conceptual):

void parse_eap9_field(char *buffer, size_t size) {
    char local_buf[256];
    // No bounds check
    memcpy(local_buf, buffer, size);
    // Process local_buf...
}

Patched Code (Conceptual):

void parse_eap9_field(char *buffer, size_t size) {
    char local_buf[256];
    if (size > sizeof(local_buf)) {
        // Handle error
        return;
    }
    memcpy(local_buf, buffer, size);
    // Process local_buf...
}

Exploitation & Lab Setup

Red Team (Exploitation)

Lab Setup:

• Target: Windows 10/11 with AutomationDirect C-More EA9 software installed (any version).
• Attacker: Kali Linux or any system with a Python environment.
• Tools: Python 3, pwntools (optional), a hex editor.

Exploitation Steps:

1. Craft Malicious EAP9 File: Use a hex editor or Python to modify a legitimate EAP9 file. Overwrite a field that is parsed without bounds checking with a large payload.
2. Deliver File: Host the file on a web server or send via email.
3. Trigger: Victim opens the file.
4. Code Execution: The payload executes, spawning a reverse shell or Meterpreter.

Example Python Script (Conceptual):

import struct

# Craft a malicious EAP9 file
payload = b"A" * 1000  # Overflow data
# ... build file structure with overflow in a specific field
with open("malicious.eap9", "wb") as f:
    f.write(payload)

Note: No public exploit code is available. This is a conceptual example.

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual file opens of .eap9 files.
• Use endpoint detection and response (EDR) to detect memory corruption events.
• Deploy YARA rules to scan for malicious EAP9 files.

Defense:

• Restrict execution of C-More EA9 to least privilege accounts.
• Use application whitelisting to prevent untrusted software.
• Enable ASLR and DEP on Windows.
• Isolate engineering workstations from the internet and corporate network.

Indicators of Compromise (IOCs)

• File Hashes: (None available yet)
• Network Indicators: Outbound connections from the engineering workstation to unknown IPs (e.g., reverse shell).
• Process Indicators: C-More EA9 process (e.g., EA9.exe) crashing or exhibiting abnormal memory usage.
• Registry/File System: Creation of suspicious files in temp directories or startup folders.
• YARA Rule: (See Detection Engineering)

Detection Engineering

YARA Rule

rule CVE_2024_11611_Malicious_EAP9 {
    meta:
        description = "Detects malicious EAP9 files exploiting CVE-2024-11611"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-11611"
    strings:
        $magic = { 45 41 50 39 } // "EAP9" magic bytes
        $overflow = { 41 41 41 41 } // Pattern of overflow (AAAA)
    condition:
        $magic at 0 and #overflow > 100
}

Sigma Rule

title: CVE-2024-11611 Exploitation Attempt via EAP9 File
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects opening of suspicious EAP9 files that may exploit CVE-2024-11611
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\EA9.exe'
        CommandLine|contains: '.eap9'
    condition: selection
falsepositives:
    - Legitimate EAP9 files from trusted sources
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-11611 Potential EAP9 Exploit - Outbound Connection"; flow:to_server,established; content:"|45 41 50 39|"; depth:4; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Systems: Disconnect C-More EA9 workstations from the network if possible.
2. User Awareness: Train users not to open EAP9 files from untrusted sources.
3. Monitor Logs: Enable detailed logging for process creation and file access.

Long-Term Fixes:

• Vendor Patch: Await an official patch from AutomationDirect. Apply as soon as available.
• Workaround: Use file integrity monitoring to detect modified EAP9 files.
• Network Segmentation: Place HMI engineering workstations in a separate VLAN with strict access controls.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.