Browsing through windows libraries I came across a few that had an intriguingly named function being resolved during run-time: DllBidEntryPoint.

The libraries referencing this API are:

• msado15.dll
• msadomd.dll
• msadox.dll
• msadrh15.dll
• msadce.dll
• msadco.dll
• msadds.dll
• msdaprst.dll
• msdarem.dll
• msdaora.dll
• msdasql.dll
• msdatl3.dll
• oledb32.dll
• sqloledb.dll

As usual, the first thing was to go to Google and soon I discovered that it’s a part of a documented tracing interface used by SQL Server called Built-in Diagnostics (BID).

One can use one of these keys:

• HKLM\Software\Microsoft\BidInterface\Loader
• HKEY_LOCAL_MACHINE\software\Wow6432Node\Microsoft\BidInterface\Loader

and add ‘:Path ‘ value name pointing to a DLL that will act as a tracing DLL.

As usual, the linked document contains all the gore details.