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Mar 22, 2004

New Virus Exploits MHTML Dumbness

We've just encountered a new virus that I can't seem to find anything about. It exploits one of the weaknesses of Mail-HTML, namely using a link to run an executable.

For Example, this mail body reads:

Received message is available at:

www.cg.org/inbox/nprotected/read.php?sessionid-3140

But the link goes to:

mhtml:mid://00005642/!cid:031401Mfdab4$3f3dL780$73387018@57W81fa70Re

displayed in source as

<A href="cid:031401Mfdab4$3f3dL780$73387018@57W81fa70Re"> www.cg.org/inbox/nprotected/read.php?sessionid-3140 </a>

When you click on it, it runs the attachment, even on my fully patched install of outlook.

Thank god the server doesn't let through executable attachments, but I have a feeling home users are in for a doozy.

Most techs I know only advise users not to click on attachments; links, until this point, have been fair-game. If this virus propogates as quickly as I think it might, we won't have time to warn the users.

After a wonderfully successful install of Mozilla Thunderbird at my parents house, I don't see any reason to keep home users on Outlook Express while it's being targeted so heavily.