Honeywell Experion PKS controllers, specifically the C200, C200E, C300, and ACE models, have recently been discovered to be vulnerable to unrestricted file uploads. This critical vulnerability, tagged as CVE-2021-38397, allows a potential attacker to remotely execute arbitrary code and cause a denial-of-service (DoS) condition on affected systems. In this detailed analysis, we'll break down the ins and outs of the vulnerability, share code snippets to illustrate the exploit, provide links to original references, and outline steps to mitigate this issue.

Vulnerability Overview

The identified vulnerability occurs when the controllers are running on firmware versions R511.00 and prior. The flaw is related to the improper handling of file uploads, which can enable a threat actor to gain unauthorized access to resources and upload arbitrary malicious files. Consequently, the attacker can execute code remotely, leading to a compromise of the system or a denial-of-service condition.

To exploit the vulnerability, an attacker would require authenticated access to the target system. However, the wide-ranging impact of this vulnerability can't be overlooked, as it poses substantial risks to systems leveraging Honeywell Experion PKS controllers.

Code Snippet Example

Let's dive into a hypothetical code snippet, illustrating how one could exploit the vulnerability by uploading a malicious file:

import requests

TARGET_URL = 'http://TARGET_IP_ADDRESS/ORIGINAL_UPLOAD_URL';
file_path = 'path/to/your/malicious_file'

headers = {
    "Authorization": "Basic REPLACE_WITH_BASE64_ENCODED_CREDENTIALS"
}

with open(file_path, "rb") as f:
    files = {"file": (file_path, f, "multipart/form-data")}
    response = requests.post(TARGET_URL, headers=headers, files=files)

print(response.status_code)
print(response.content)

In this Python script, we're targeting the Honeywell Experion PKS controller's file upload functionality. By sending a POST request impersonating an authenticated user, we attempt to upload a malicious payload that, once executed, would allow an attacker to compromise the system.

Original References

For in-depth technical information regarding the vulnerability, and to keep yourself updated on any new developments, be sure to refer to the following sources:

1. NIST National Vulnerability Database (CVE-2021-38397): https://nvd.nist.gov/vuln/detail/CVE-2021-38397
2. Honeywell Product Security Notification: https://www.honeywellprocess.com/en-US/support/Product-Information/Notices/Pages/Security-Notification-ECP_21-0281.aspx

Mitigation Strategies

Fortunately, Honeywell has released a firmware update addressing the CVE-2021-38397 vulnerability; users are advised to apply the R511.90 update to resolve this issue. Other recommended steps to minimize the potential impact of this vulnerability include:

Conclusion

CVE-2021-38397 is a critical vulnerability in Honeywell Experion PKS controllers that can lead to remote code execution and Denial-of-Service conditions. System administrators must take this threat seriously and follow best practices to maintain the security of systems leveraging these controllers. Updating firmware and diligently monitoring user access are among the key countermeasures to combat this vulnerability effectively.

Timeline

Published on: 10/28/2022 02:15:00 UTC
Last modified on: 11/02/2022 18:12:00 UTC