ietf-mta-filters
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Re: extensions and sieve

2003-02-03 17:12:39
On Tuesday 04 February 2003 00:13, Jutta Degener wrote:
<snip :param>
  But maybe this is overkill.

It isn't, but this is:

- RFC 2047 prohibits RFC 2047-encoding of filenames.
  (They're not the right kind of token.)

  In reality, many clients do RFC 2047-encode and -decode names,
  and I think sieve code matching against file names in order
  to prevent use of certain extensions needs to, ironically,
  RFC 2047-decode the wrong tokens in spite of what the RFC itself
says.
<snip>

They should decode rfc2231, of course, but leave rfc2047 alone in 
parameters. The only client I am aware of that is so broken to produce 
rfc2047 in parameter values is - guess what - Outlook (I think mutt had 
this bug in one or two minor revisions, too, but I don't know, so I 
won't claim it).

As a general note, this mimeheader searching is of course failing for 
encrypted content, so if you try to filter out .vbs (which, I suppose, 
are VisualBasic scripts), you're better off hooking up a custom 
solution (read: ADKs, bah!) into your Sieve engine's spamtest/virustest 
framework.

Marc

-- 
History teaches that grave threats to liberty often come in times of
urgency, when constitutional rights seem too extravagant to endure.
                                  -- Justice Thurgood Marshall, 1989

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