CVE-2020-12526

BECKHOFF: DoS-Vulnerability for TwinCAT OPC UA Server and IPC Diagnostics UA Server

Published May 13, 2021 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
TwinCAT OPC UA Server in versions up to 2.3.0.12 and IPC Diagnostics UA Server in versions up to 3.1.0.1 from Beckhoff Automation GmbH & Co. KG are vulnerable to denial of service attacks. The attacker needs to send several specifically crafted requests to the running OPC UA server. After some of these requests the OPC UA server is no longer responsive to any client. This is without effect to the real-time functionality of IPCs.

Remediation

Vendor Solution

For devices running Windows but not Windows CE or TwinCAT/BSD please get a recent version of the OPC UA servers through the conventional ways and update your system. For devices running Windows CE please request a recent image via Beckhoff’s support and apply it to your device. For the product CX8091 please use firmware version "CX8091_CE600_LF_v356f_TC211R3_B2306_v2" or later. Please note that the updated OPC UA server leaves less RAM available to your application on the CX8091.


Vendor Workaround

Consider disabling the IPC Diagnostics Server by stopping and disabling the corresponding Windows service or service. For example this can be achieved with the following PowerShell commands: Stop-Service -Force -Name DevMgrSvr-UA Set-Service -Name DevMgrSvr-UA -StartupType Disabled Alternatively consider limiting access to the TCP port the OPC UA server is listening on. This can happen with a dedicated firewall appliance which sits in front of an affected device. Alternatively at the device the Windows firewall can be configured to limit access to the TCP port.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2020-4828 TwinCAT OPC UA Server in versions up to 2.3.0.12 and IPC Diagnostics UA Server in versions up to 3.1.0.1 from Beckhoff Automation GmbH & Co. KG are vulnerable to denial of service attacks. The attacker needs to send several specifically crafted requests to the running OPC UA server. After some of these requests the OPC UA server is no longer responsive to any client. This is without effect to the real-time functionality of IPCs.
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
CERTVDE
Published
Updated
Sep 16, 2024, 6:29 PM
Reserved
Apr 30, 2020, 12:00 AM
Status
Modified
Published
May 13, 2021, 2:15 PM
Modified
Jun 17, 2026, 2:51 AM