OPC DA failed to connect after Windows DCOM Server Security Feature Enable|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

Thank you for bringing this to our attention.

I have raised the issue with our contacts at Microsoft to get more information.

Based on my reading of the available information I suspect that many OPC applications will have to change the parameters they pass to CoCreateInstance or CoInitializeSecurity.

Are you in a position to modify the client and server code to experiment with different parameters?

Correct links are:

https://msrc.microsoft.com/upd.....2021-26414

https://support.microsoft.com/.....ed901c769c

At this point your options are:

1) Use an OS other than Windows 10 or Windows Embedded 8.1;

2) Update your applications to call RpcBindingSetAuthInfo() and set the RPC_C_AUTHN_LEVEL_PKT_INTEGRITY flag (needs confirmation).

3) Use local DCOM + OPC UA Gateway to provide remote access;

4) Use local DCOM + OPC DCOM tunneler to provide remote access.

1) Did you check Windows 7?

Note that using an end of life Windows OS is generally a bad idea but a lot of existing factory systems do have old systems and should be unaffected by the change but will still be affected by the security vulnerability that led MS to make the change in the first place.

2) Someone who has this problem and has access to their COM client/server code needs to verify that this fix works.

3) Example of a COM to UA gateway:

https://www.unified-automation.....teway.html

Any product that works as a 'protocol converter' such as KepServerEx could also be used.

4) Example of a DCOM tunneller:

https://www.matrikonopc.com/op.....eller.aspx