What are the security/privacy concerns with MHTML (.mht) files?

Question

My customer is currently using MHT files for storing offline representations of browsed web pages. The files are saved and later viewed in Internet Explorer.

When viewing the files we would like to be sure there is absolutely no network activity to the original site or any other site - the content should be browsed 100% offline, and should not have any special "local" privileges as well (i.e. access to file:// protocols etc.). We would like to keep JS running if possible, and we can suffer to consequences of disabled features because of working offline.

We are willing to change the viewer or even the file format (and convert all old mht files as well) if a better solution is suggested.

Thanks for any help on this,

Udi

Answer 1

It is not possible to guarantee that there will be no network activity unless you go to offline mode in Internet explorer. Though the advantage of saving a web page to a mht file is that all the info for displaying the page (including images) are stored in one file instead of several files and folders, making archiving easy, if the web content has links to other pages, clicking on links will initiate network activity.

One option is to post-process the mht file and replace the url links with just the title of the link. For e.g, replacing

<A=20
title=3D"Conduction band"=20
href=3D"http://en.wikipedia.org/wiki/Conduction_band">conduction =
bands</A>

with "Conduction band".