Documentation on the SEE_MASK_NOZONECHECKS environment variable

Question

I'm helping to try track down and reproduce an issue with our web application in Internet Explorer for one of our clients. Their browser process is launched with the SEE_MASK_NOZONECHECKS environment variable set. I'm trying to find out the changes that variable will have on Internet Explorer's behaviour. A Google search reveals a single Microsoft Knowledge Base article that only says it will disable all Zone Checking, and a whole bunch of forum posts with similarly vague information.

Does anyone know of any official documentation that provides more detailed information about the SEE_MASK_NOZONECHECKS environment variable?

Answer 1

It seems to be referenced in the SHELLEXECUTEINFO structure, and directly affects the behavior of the IAttachmentExecute interface, specifically the CheckPolicy method. From MSDN:

IAttachmentExecute::CheckPolicy examines a set of properties known collectively as evidence. Anything used to determine trust level is considered evidence.

Zone is one of the values examined by this function, which can be set with the SetReferrer method. Seems like having SEE_MASK_NOZONECHECKS set causes the Zone check to be skipped here.

SHELLEXECUTEINFO Structure

IAttachmentExecute Interface