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OPC Router and DCOM Hardening (CVE-2021-26414, KB5004442)

This FAQ discusses how the OPC Router product is affected by the changes made by Windows updates that are described in Microsoft's KB5004442 advisory regarding Windows Updates that have been rolled out to affected operating systems by Microsoft since June 8, 2021 to address vulnerabilities in DCOM described in CVE-2021-26414. Due to upcoming enforcement actions by Microsoft, users may need to take actions described in this FAQ. This FAQ is a supplement to our overall detailed technical FAQ regarding DCOM Hardening which contains information that is common to all products affected by DCOM hardening. You may also request our free detailed Remote OPC DA Classic (DCOM) Configuration Guide here with recommendations for DCOM setting configuration on OPC DA client and server machines where connections will be remote (client and server on separate machines).

Contents

Specific Product Editions/Versions or Use Cases Affected and Not Affected

All versions of OPC Router are affected for its OPC DA Client interface if you are connecting to OPC DA servers over a network. Many users will NOT be affected, as described below. 
Affected:
  • Connections to OPC DA servers running on different computer or virtual from OPC Router, which means DCOM is being used.
Not Affected:
  • Connections to OPC DA Servers located on the same computer or virtual as OPC Router 
  • OPC UA client connections from OPC Router 
  • OPC UA server interfaces exposed by OPC Router

General Relevant Product Information

Is OPC UA available in this product as an alternative?  Yes, OPC Router is also an OPC UA client and that functionality is included with your OPC DA client license.

Operating System Support Details - OPC Router specifications 
Respects Component Services Settings? Yes
Uses Hard-Coded Co-Initialize security Calls? No.
DCOM Hardening Specific Updates Relevant and Available? None required, however we always recommend running the most current version of the product and reserve the right to limit support for non-current software. 
Obtaining Current Product Versions Users on active support & maintenance agreements are entitled to update at no additional cost. Current OPC Router version is available on the OPC Router website. Contact us with your OPC Router license details to check your support status and, if necessary, obtain quote for reinstatement of support & maintenance.

Product Specific Settings Recommendations

Because OPC Router respects the Component Services DCOM Config settings, see our general DCOM hardening FAQ recommendations. You may also request our free detailed Remote OPC DA Classic (DCOM) Configuration Guide here with recommendations for DCOM setting configuration on OPC DA client and server machines where connections will be remote (client and server on separate machines).

Remember that if you make any changes to DCOM settings in Component Services, you MUST restart the OPC Router runtime for the product to know about the changes. If they make changes on the OPC Server side, the OPC server must also be restarted. This is the nature of DCOM settings because applications using DCOM can only get their security settings one time at startup.

 
After March 14, 2023, because you will no longer be able to disable the changes described in the KB5004442 advisory with a registry entry, you must have prepared any affected systems requiring changes by adjusting your computers' global DCOM Authentication Level settings to use the Packet Integrity option (per the screenshot below), migrated to OPC UA, or implemented another DCOM alternative. For general DCOM configuration recommendations beyond the required DCOM Authentication Level (which is beyond the scope of this FAQ), consult our DCOM Tutorial; HOWEVER, the recommendations found here regarding Authentication Level OVERRIDE/SUPERSEDE anything in our DCOM tutorial. 
Default_DCOM_Authentication_Level

 

What About Other Vendors' OPC Classic Servers Being Used with OPC Router?

As covered in our DCOM Hardening FAQ, all OPC Classic client and server applications have two methods that may have been implemented with respect to handling DCOM Authentication Level. They can:

  1. Set DCOM security settings programmatically, or

  2. Allow their application to use settings in the Windows Component Services DCOM Config utility to determine the settings

OPC Router uses method #2, so as long as you have configured the default DCOM Authentication Level to use Packet Integrity as covered in our DCOM Hardening FAQ, OPC Router OPC DA client connections should continue to work. 

 

For your OPC DA Classic server applications being used with OPC Router, you will need to consult with that server application vendor to confirm which method they are using for DCOM security settings.

 

For OPC DA Classic Server Vendors Using Method #1, that vendor will either have to provide a version of their software that allows the DCOM Authentication Level to be configured in the software or a version where the hard-coded DCOM Authentication Level is Packet Integrity level.

 

For OPC Classic Server Vendors Using Method #2 like OPC Router, making the previously indicated adjusted of computer's global DCOM Authentication Level to Packet Integrity should be all that is required (this change needs to be performed on both the OPC Classic client and server machines).

 

If you're unsure which method your other OPC DA Classic server software vendors are using, ask them how they are addressing Microsoft's DCOM hardening changes as they apply to their OPC Classic solutions.

Considerations Regarding Alternatives to DCOM

DCOM has been a challenge for users making remote OPC Classic connections for many years, due to the subtle nuances of DCOM operation between different Windows operating systems and different network architectures. As such, there are several alternatives available for users that prefer to migrate away from DCOM entirely ahead of these DCOM hardening changes as a method for future-proofing remote connections from any further Microsoft changes to DCOM security.

  1. Simply migrate all OPC Classic client and server applications to reside on the same computer (resulting in local only OPC Classic connections that are not susceptible to DCOM security changes).
  2. Migrate from OPC Classic to OPC UA wherever possible for remote connections. OPC Router, for example, is also an OPC UA client and server.  One of the key benefits of OPC UA is increased security without the pitfalls of DCOM for remote connections.  To learn more about OPC UA, click here.
  3. If you are unable to enable OPC UA on your OPC DA Server application so it could since OPC Router is an OPC UA client, you could put the DataHub OPC Gateway on your server machine, so that OPC Router is talking to the gateway as an OPC UA server, and then the gateway communicates via OPC DA locally to the server on the same machine. Contact us for details. 
  4. You could also use OPC Tunneling with the OPC Router using DataHub; however because OPC Router is already an OPC UA client and server use of the OPC Gateway to convert your OPC DA server to UA will be more cost effective in most cases. Contact us to discuss if you have any confusion or need help.
      Disclaimer: You are ultimately responsible to work with your IT/OT teams on handling the changes to your systems. Software Toolbox support cannot and will not make changes to customer systems for them. This information is provided for reference and is based on our best commercially reasonable efforts to gather, validate and aggregate this knowledge and is provided under and subject to our standard terms and conditions.