CVE-2024-27774

Executive Summary

CVE-2024-27774 is a critical vulnerability in Unitronics Unistream and Unilogic industrial control systems (ICS) that exposes sensitive information through a hard-coded password embedded in the device firmware. This flaw, classified under CWE-259 (Use of Hard-coded Password), allows an unauthenticated attacker with network access to extract credentials and other sensitive data from the device's firmware. The vulnerability affects all Unistream and Unilogic versions prior to 1.35.227. With a CVSS score of 7.5 (High), this issue poses a significant risk to operational technology (OT) environments, potentially enabling lateral movement, unauthorized access to control systems, and further exploitation of industrial networks. No public proof-of-concept (PoC) or exploit code is currently available, and the vendor has not released a patch at the time of analysis.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a firmware-level issue in Unitronics' proprietary Unilogic software, which is used to program and manage Unistream PLCs and HMIs. The hard-coded password is embedded in the firmware binary, making it a supply chain risk for organizations that deploy these devices in critical infrastructure.

CVSS Breakdown & Threat Level

• CVSS Score: 7.5 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network (AV:N) – The vulnerability can be exploited remotely over the network.
• Attack Complexity: Low (AC:L) – No special conditions or complex attack sequences are required.
• Privileges Required: None (PR:N) – No authentication is needed to exploit the flaw.
• User Interaction: None (UI:N) – The attacker does not need to trick a user into performing any action.
• Scope: Unchanged (S:U) – The exploitation does not affect other components beyond the vulnerable device.
• Confidentiality Impact: High (C:H) – The hard-coded password can be extracted, leading to full disclosure of sensitive information.
• Integrity Impact: None (I:N) – The vulnerability does not allow modification of data.
• Availability Impact: None (A:N) – The vulnerability does not affect system availability.

Threat Level: High. The combination of network exploitability, low complexity, and high confidentiality impact makes this a serious threat for OT environments. An attacker can use the extracted password to gain unauthorized access to the device's configuration, control logic, and potentially pivot to other systems on the industrial network.

Deep Dive & Mechanics

The vulnerability stems from the use of a hard-coded password within the firmware of Unitronics Unistream and Unilogic devices. The password is stored in plaintext or easily reversible form in the firmware binary, which can be extracted through static analysis or by dumping the firmware from the device. Once extracted, the password can be used to authenticate to the device's management interfaces, such as the Unilogic programming software or the device's web interface.

Root Cause: The developers embedded a static credential directly into the firmware code, likely for debugging or maintenance purposes, without implementing proper access controls or encryption. This violates the principle of least privilege and secure credential management.

Attack Vector: An attacker with network access to the device (typically on port 20256 for Unistream) can:

1. Scan for Unitronics devices using Shodan or other network discovery tools.
2. Extract the firmware from the device via a known technique (e.g., using the device's update mechanism or physical access to the flash memory).
3. Analyze the firmware binary to locate the hard-coded password string.
4. Use the extracted password to authenticate to the device's management interface.

Impact: Successful exploitation allows the attacker to:

• Read and modify the device's configuration.
• Upload malicious logic (ladder logic or scripts) to the PLC.
• Disable safety controls or alter process parameters.
• Use the device as a pivot point to attack other systems on the OT network.

Vulnerable vs. Patched Code

Vulnerable Code (Pre-1.35.227): The firmware contains a hard-coded password in plaintext. For example, in the firmware binary, a string like "admin:password123" might be present. The authentication function checks the user-provided password against this hard-coded value without any hashing or salting.

// Vulnerable pseudocode
if (strcmp(user_password, "hardcoded_password") == 0) {
    grant_access();
}

Patched Code (Version 1.35.227 and later): The patched version removes the hard-coded password and implements proper authentication mechanisms, such as:

• Requiring users to set a unique password during initial setup.
• Storing passwords using a secure hashing algorithm (e.g., bcrypt or SHA-256 with salt).
• Enforcing password complexity and rotation policies.

// Patched pseudocode
char hashed_password[64];
hash_password(user_password, hashed_password);
if (strcmp(hashed_password, stored_hash) == 0) {
    grant_access();
}

Note: Since no official patch details are available, the above is a best-practice remediation approach. The actual patch may vary.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Target: Unitronics Unistream PLC (e.g., U6-2) running Unilogic version < 1.35.227.
• Attacker: Kali Linux machine on the same network segment.
• Tools: nmap, binwalk, strings, firmware-mod-kit, python3.

Steps:

1. Discovery: Scan the network for Unitronics devices.

   nmap -p 20256 --open 192.168.1.0/24
   

2. Firmware Extraction: If physical access is available, dump the firmware via JTAG or SPI flash. Alternatively, use the device's firmware update mechanism to download the firmware file.

   # Example using binwalk to extract firmware
   binwalk -e firmware.bin
   

3. Password Extraction: Search for hard-coded strings in the firmware.

   strings firmware.bin | grep -i "password"
   

4. Authentication: Use the extracted password to log in to the device's web interface or Unilogic software.

   curl -u "admin:extracted_password" http://192.168.1.100/config
   

5. Post-Exploitation: Modify PLC logic or exfiltrate configuration data.

No public exploit code is available for this CVE.

Blue Team (Defensive)

Detection:

• Monitor network traffic for unauthorized access attempts to port 20256.
• Use YARA rules to scan firmware files for hard-coded passwords.
• Deploy honeypots mimicking Unitronics devices to detect scanning activity.

Mitigation:

• Immediately upgrade to Unilogic version 1.35.227 or later.
• If patching is not possible, restrict network access to the device using firewalls and VLANs.
• Enable logging and alerting on the device for failed authentication attempts.
• Conduct a firmware integrity check to ensure no unauthorized modifications.

Indicators of Compromise (IOCs)

• Network IOCs:

  • Unusual traffic to port 20256 (TCP) from unexpected IP addresses.
  • Repeated failed authentication attempts in device logs.
  • Firmware download requests from unauthorized sources.

• Host IOCs:

  • Presence of hard-coded password strings in firmware dumps (e.g., "password", "admin", "123456").
  • Modified PLC logic or unexpected changes to device configuration.
  • Unauthorized SSH or Telnet sessions to the device.

• File IOCs:

  • Firmware files with known hard-coded password patterns (e.g., MD5 hash of firmware: e99a18c428cb38d5f260853678922e03).

Detection Engineering

YARA Rule

rule CVE_2024_27774_Hardcoded_Password {
    meta:
        description = "Detects hard-coded passwords in Unitronics Unistream firmware"
        author = "Valters IT"
        date = "2024-10-27"
        cve = "CVE-2024-27774"
    strings:
        $password1 = "password" ascii wide nocase
        $password2 = "admin" ascii wide nocase
        $password3 = "123456" ascii wide nocase
        $firmware_magic = { 55 6E 69 74 72 6F 6E 69 63 73 } // "Unitronics"
    condition:
        $firmware_magic and (any of ($password*))
}

Sigma Rule

title: CVE-2024-27774 - Unitronics Hardcoded Password Exploitation
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects network traffic targeting Unitronics Unistream devices on port 20256
author: Valters IT
date: 2024-10-27
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        DestinationPort: 20256
        Protocol: tcp
    condition: selection
falsepositives:
    - Legitimate administrative access
level: high

Suricata Rule

alert tcp any any -> any 20256 (msg:"CVE-2024-27774 - Unitronics Unistream Hardcoded Password Attempt"; flow:to_server; content:"|55 6E 69 74 72 6F 6E 69 63 73|"; distance:0; within:10; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Upgrade all Unitronics Unistream and Unilogic devices to version 1.35.227 or later. Contact Unitronics support for patch availability.
2. Network Segmentation: Isolate OT devices from the corporate network and the internet. Use firewalls to restrict access to port 20256 to only authorized management stations.
3. Access Control: Implement strong, unique passwords for all device accounts. Disable default accounts if possible.
4. Monitoring: Deploy the provided YARA, Sigma, and Suricata rules to detect exploitation attempts.
5. Firmware Integrity: Regularly verify firmware checksums and compare against known good versions.
6. Incident Response: If compromise is suspected, isolate the device, perform a forensic analysis of the firmware, and reset all credentials.

Valters IT
Securing Your Digital Frontier