[MlMt] Conditional (per account/per sender/recipient) behavior - PGP and images

Bill Cole mmlist-20120120 at billmail.scconsult.com
Sun May 30 11:58:10 EDT 2021

On 2021-05-30 at 01:53:46 UTC-0400 (Sun, 30 May 2021 07:53:46 +0200)
Patrik Fältström via mailmate <mailmate at lists.freron.com>
is rumored to have said:

> As MM is already doing some guessing/decision making on what are 
> downloads and what are trackers,

Where do you see "guessing" happening?

The only distinctions I see MM making are very standardized and 
deterministic. Images included in messages are handled depending on 
their Content-Disposition headers (inline or attachment) and images 
referenced in HTML which are not included in messages are not loaded 
unless they pass the criteria in the Security->Image Blocking 
preferences pane. I do not know of any circumstances where it makes any 
more nuanced decision about the handling of non-text objects.

1x1 trackers are often detectable because in email, remote loading is 
widely disabled and it can ruin layout to not know the size of a missing 
image. However, people using images for tracking have also figured out 
that if they are using images as images, there's no reason that they 
need to have a special 1x1 tracking image. Every image in a HTML email 
can carry an identifying tag in its URL and hence be used as a tracker. 
If an image URL includes 5 arbitrary characters, it can be a tracker. 
Obviously it CAN be a tracker with a smaller target-ID, but ~30 bits is 
a scale adequate for almost all purposes. It's not really feasible for 
client software like MM to make an accurate  complete judgment of 
whether a particular external reference is a tracker or not.

Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire

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