mailing list archives
Re: UPDATE: Re: REFRESH: EUDORA MAIL 5.1.1
From: full-disclosure () lists netsys com (http-equiv () excite com)
Date: Fri, 26 Jul 2002 09:48:17 -0000
Nick FitzGerald <nick () virus-l demon co uk> said:
Jeff Kell <jeff-kell () utc edu> replied to http-equiv () malware com:
[I thought I replied to "http-equiv"'s message earlier, but on
checking I sent it direct, not to the lists...]
Just tested something here. Typically IE can or will open files
depending what the contents are regardless of the extension
is: <html> tag in a gif or some other file type should or can be
rendered by IE for what the contents are, not the extension.
The Windows run function (IE viewer) ignores the extension (sort
the file is in a portable OLE-type format. For example, go in
create "foo.doc". Exit and rename "foo.doc" to "foo.fubar".
click "foo.fubar" and Word opens up. Same for Excel and other
If the extension is known, it appears to try and use it. If not,
will look for OLE-extensions and launch what matches.
It's the other way around -- if a file's extension is not registered
on the system trying to "run" (or "open") the file, depending on
it is being "opened", some further checks than just "what is
registered to handle this extension" are made. One of those checks
determines whether the file is apparently internally an OLE2 file,
and if so the application registered to handle the CLSID of the
directory entry in the OLE2 file is directed to open the file. If
that CLSID is also not registered then the usual "Open With..."
dialog appears. Another file type tested for in this process is
DOS ("MZ") EXE format, which can be run "as normal", depending on
"open" method used, depsite having been renamed to a non-EXE
Thus, "http-equiv"'s discovery that a non-extensioned EXE could be
launched through one of these code execution holes is not all that
For clarity's sake, in this particular instance it was only the meta
refresh that was non-extensioned.
In the embedded folder we had / have:
malware [the mhtml file -- no extension]
<META http-equiv=refresh content="1;
The refresh tag is pointing to malware -- what it does is skip over
the non-extensioned mhtml file, and instead, open malware.exe