The Claroty Research Team has discovered a severe vulnerability (CVE-2021-22681, CVSS 10.0) in a mechanism that verifies communication between Rockwell Automation PLCs and engineering stations. The vulnerability affects Studio 5000 Logix Designer, RSLogix 5000, and many Logix Controllers.
Exploiting this flaw enables an attacker to remotely connect to almost any of the company's Logix programmable logic controllers (PLCs), and upload malicious code, download information from the PLC, or install new firmware.
The vulnerability lies in the fact that Studio 5000 Logix Designer software may allow a secret cryptographic key to be discovered. This key is used to verify communication between Rockwell Logix controllers and their engineering stations. If successfully exploited, this vulnerability could allow a remote, unauthenticated attacker to bypass this verification mechanism and connect to Logix controllers.
An attacker who is able to extract the secret key would be able to authenticate to any Rockwell Logix controller. These secret keys digitally sign all communication with the Rockwell PLCs; the PLCs verify the signature and authorize communication between it and the Rockwell engineering software. An attacker with this key could mimic a workstation and therefore be able to manipulate configurations or code running on the PLC (upload/download logic), and directly impact a manufacturing process.
Affected versions include: Rockwell's Studio 5000 Logix Designer (versions 21 and later) and RSLogix 5000 (versions 16-20), as well as Rockwell Logix Controllers (CompactLogix 1768, 1769, 5370, 5380, 5480, 5550, 5560, 5570, 5580), Drive Logix (5560, 5730, 1794-L34), Compact GuardLogix (5370 and 5380), GuardLogix (5570 and 5580), and SoftLogix 5800.
An advisory published Thursday by the Industrial Control System Cyber Emergency Response Team (ICS-CERT), describes the vulnerability as requiring low skill level to exploit.
Claroty privately disclosed the flaw to Rockwell in 2019; researchers from South Korea's Soonchunhyang University's Lab of Information Systems Security Assurance, and Kaspersky Lab, were also credited by ICS-CERT as having independently discovered the vulnerability.
Rockwell Automation recommends a number of specific mitigations including putting the controller's mode switch to "Run" mode and deploying CIP Security for Logix Designer connections. CIP Security prevents unauthorized connections when deployed properly.
Rockwell Automation also recommends a number of generic mitigations to blunt the effects of this vulnerability, starting with proper network segmentation and security controls such as minimizing exposure of control systems to the network or the internet. Control systems, Rockwell said, should be behind firewalls and isolated from other networks whenever feasible. Secure remote access is also suggested; at a minimum, using a VPN to connect to a device.
The ICS-CERT advisory includes all Rockwell mitigation advice, including a number of recommendations for each product family and version. It also recommends a number of detection methods if users suspect configurations have been modified. Those include:
Monitor controller change log for any unexpected modifications or anomalous activity.
If using v17 or later, utilize the Controller Log feature.
If using v20 or later, utilize Change Detection in the Logix Designer Application.
If available, use the functionality in FactoryTalk AssetCentre to detect changes.
CWE-547 USE OF HARD-CODED, SECURITY-RELEVANT CONSTANTS:
Optigo Networks Visual BACnet Capture Tool and Optigo Visual Networks Capture Tool version 3.1.2rc11 are vulnerable to an attacker impersonating the web application service and mislead victim clients.
Optigo Networks recommends users to upgrade to the following:
CVSS v3: 7.5
CWE-288 AUTHENTICATION BYPASS USING AN ALTERNATE PATH OR CHANNEL:
Optigo Networks Visual BACnet Capture Tool and Optigo Visual Networks Capture Tool version 3.1.2rc11 contain an exposed web management service that could allow an attacker to bypass authentication measures and gain controls over utilities within the products.
Optigo Networks recommends users to upgrade to the following:
CVSS v3: 9.8
CWE-547 USE OF HARD-CODED, SECURITY-RELEVANT CONSTANTS:
Optigo Networks Visual BACnet Capture Tool and Optigo Visual Networks Capture Tool version 3.1.2rc11 contain a hard coded secret key. This could allow an attacker to generate valid JWT (JSON Web Token) sessions.
Optigo Networks recommends users to upgrade to the following:
CVSS v3: 7.5
CWE-912 HIDDEN FUNCTIONALITY:
The "update" binary in the firmware of the affected product sends attempts to mount to a hard-coded, routable IP address, bypassing existing device network settings to do so. The function triggers if the 'C' button is pressed at a specific time during the boot process. If an attacker is able to control or impersonate this IP address, they could upload and overwrite files on the device.
Per FDA recommendation, CISA recommends users remove any Contec CMS8000 devices from their networks.
If asset owners cannot remove the devices from their networks, users should block 202.114.4.0/24 from their networks, or block 202.114.4.119 and 202.114.4.120.
Please note that this device may be re-labeled and sold by resellers.
Read more here: Do the CONTEC CMS8000 Patient Monitors Contain a Chinese Backdoor? The Reality is More Complicated….
CVSS v3: 7.5
CWE-295 IMPROPER CERTIFICATE VALIDATION:
The affected product is vulnerable due to failure of the update mechanism to verify the update server's certificate which could allow an attacker to alter network traffic and carry out a machine-in-the-middle attack (MITM). An attacker could modify the server's response and deliver a malicious update to the user.
Medixant recommends users download the v2025.1 or later version of their software.
CVSS v3: 5.7
