Subject: RE: [Asrg] "more readable"

From: Vernon Schryver <[email-masked]>
Date: Mon, 23 Jun 2003 13:15:50 -0600 (MDT)

> From: "Hallam-Baker, Phillip" <[email-masked]>

> It is not that difficult to strip out HTML tags with a FSR of about
> 10 states. 
> ...

For now, I think a simplistic parser with fewer than 10 states related to
HTML is sufficient, but I anticipate needing a more complicated mechanism.

It's not merely that you need somewhat more than 10 states to detect
elements (as opposed to tags) in order to know, for example, where
font and color settings end.  Netscape 7 and Internet Explorer do
various visible things that depends on parsing that can only be done
with some backtracking.  A trivial example is that both consider
<!--this--> to be a comment but <!--not-this-- > contrary to
http://www.w3.org/TR/html401/intro/sgmltut.html#idx-HTML
Netscape 7 and Internet Explorer consider <!--stuff<and><nonsense-- >
as two tags instead of one comment.

> Strange tags and com<!-- stupid stuff -->ments can be elided but they
> are a very reliable spam indicator. If email has an html comment in the
> middle of a spamword that increases the probability it is spam.
>
> This is one case of a spam sender countermeasure that backfires.

That popular filters have been adjusted in that direction may be why
the more advanced spammers have stopped using that particular tactic.

Vernon Schryver    [email-masked]

_______________________________________________
Asrg mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/asrg

---

From: "Hallam-Baker, Phillip" <[email-masked]>
Date: Mon, 23 Jun 2003 09:28:14 -0700

> That's true of privacy and security complaints but not spam. 
> A safe and sane HTML-enabled MUA that doesn't dereference URLs and
> never executes scripts without the explict informed opinion of a human
> user would be an irritant for spam filtering.  Spam filtering must
> deal with <strange tags> and <!--comments-->, just to name two things
> that are easy to handle and not mentioning other things that are more
> hassle since there's no reason instruct the slower spammers reading
> this mailing list.

	Phill