"You're in the doghouse mate!"

Once upon a time you could see HTML document thumbnails in windows explorer and all shell-compatible file managers like xplorer². Then the security madness kicked in and ever since windows XP SP1 you have no HTML previews. For XP thumbnails could be reenabled with a simple registry hack. Surely something similar would work in windows vista?

I tried my best folks but I have failed. I write this article so that you don't waste your time with similar attack vectors. Here's what I've tried.

Using the registry snooping techniques we've discussed before, I found the object that renders HTML previews in windows XP {EAB841A0-9550-11CF-8C16-00805F1408F3}, which is serviced by SHIMGVW.DLL, a file in the system32 folder. This DLL exists in windows vista too, but it is much smaller in size, implying that much of the original functionality has been removed.

I searched vista's registry for "EAB841A0" to discover traces of the thumbnail extractor object to no avail. But what the heck, I thought I'd give it a go anyway. Perhaps it is still hosted in vista's version of SHIMGVW.DLL but not registered? I tried the following registry script exported from windows XP:

Windows Registry Editor Version 5.00 [HKEY_CLASSES_ROOT\htmlfile\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}] @="{EAB841A0-9550-11cf-8C16-00805F1408F3}" [HKEY_CLASSES_ROOT\CLSID\{EAB841A0-9550-11CF-8C16-00805F1408F3}] @="HTML Thumbnail Extractor" [HKEY_CLASSES_ROOT\CLSID\{EAB841A0-9550-11CF-8C16-00805F1408F3}\InprocServer32] @="C:\\WINNT\\system32\\shimgvw.dll" "ThreadingModel"="Apartment"

That would have been too easy, wouldn't it? No thumbnails still. Then I added the object to the approved list (HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved), no change. This approved list doesn't seem to be used in vista anyway.

Getting desperate, I tried overwritting XP's version of SHIMGVW.DLL over to vista — not as easy as it sounds but I managed it in the end booting in XP and using unlocker to delete the stubborn DLL from vista's system32 folder. No HTML thumbnails either....

I haven't given up on this one, but for the moment I have to admit defeat. Anyone with any ideas please come forward!

Post a comment on this topic