Puritanical Security? And a Few Other Notes on HTML Help

I was going through some CHM help files the other day and I wound up copying one of the links to the clipboard and tossing it into Maxthon. I wasn't even really aware of what I was doing (just plodding along mindlessly) so I was rather surprised when I was presented with the following dialog:


Security Warning !

Using MK: protocol in browser may cause puritanical security problems.
Do you really want to enable this protocol during this session?

Of course, I had no desire to cause puritanical security problems, so I went with the default "No". The URL I had copied was in fact a "Microsoft Infotech" protocol link in the form of:
mk:@MSITStore:f:\file.chm::/Whatever/Whatever.html

The InfoTech protocol has changed several times over the last few years to reduce security vulnerabilities in HTML help. See MS05-026: A vulnerability in HTML Help could allow remote code execution and MS04-023: Vulnerability in HTML Help could allow code execution for more information.

Another issue that is seen rather frequently is the inability to open CHM / HTML Help files from a network path (UNC path or mapped drive). The article "You cannot open remote content by using the InfoTech protocol after you install security update 896358, security update 840315, or Windows Server 2003 Service Pack 1" discusses various registry settings that can be manipulated to allow the display of content in CHM files in this scenario.

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