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Re: [ietf-smtp] [Proposal] confusing parts of the mail system, was 250-MARKDOWN

Ned Freed <ned.freed@mrochek.com> Mon, 14 January 2019 16:22 UTC

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Cc: Ned Freed <ned.freed@mrochek.com>, ietf-smtp <ietf-smtp@ietf.org>
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Date: Mon, 14 Jan 2019 08:18:28 -0800
From: Ned Freed <ned.freed@mrochek.com>
In-reply-to: "Your message dated Sun, 13 Jan 2019 13:40:24 -0500" <alpine.OSX.2.21.1901131338540.28369@ary.qy>
References: <CAOEezJTxTN9x_JFXgLidj9k8NVgFTRyqyQc4Aak8UEQuvjiM0w@mail.gmail.com> <20190109143529.33122200C76CAD@ary.local> <460d4589-5517-3762-5764-7474523dd09b@digilicious.com> <01R1U95VCAHI00004L@mauve.mrochek.com> <74e22977-8ee8-c762-4882-b56e5911430e@digilicious.com> <CALui8C2qzp_jBo=YHA+XXBGF6+jigDeEaX24L2bohQBdaXKHwg@mail.gmail.com> <alpine.OSX.2.21.1901101442230.18680@ary.qy> <CALui8C1FHhq0Bc1GOXe1xQ+w5c7td3BuOEhBmB6Jf0DZbXLYXw@mail.gmail.com> <alpine.OSX.2.21.1901101541030.19026@ary.qy> <0f692ab9-c71c-8c15-b3e1-e151c357477a@digilicious.com> <alpine.OSX.2.21.1901111624090.22582@ary.qy> <01R1YI5W24JK00004L@mauve.mrochek.com> <alpine.OSX.2.21.1901131338540.28369@ary.qy>
To: John R Levine <johnl@taugh.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf-smtp/4nlF8rEpAbmqitXcj0cWxD3rD5U>
Subject: Re: [ietf-smtp] [Proposal] confusing parts of the mail system, was 250-MARKDOWN
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> >>  Yeah, I think I've seen MTAs that do that.
> >
> > They do. At submission, security gateway, and final delivery.

> I see that Thunderbird will store attached files on Box or similar
> services. although it just edits the link into the text of the message
> rather than making it a separate MIME part.

You will also find cases where such links are themselves replaced with a
redirection through some sort of filter, in order to prevent the attack
where a message is sent with a reference to something innocuous that
gets by filter checks, but is subsequently replaced with malware.

IME these sorts of filter mechanisms work poorly, but good luck getting
rid of them.

				Ned

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