Anubis and Mail Clients (MUA) to support emails with embedded links to images ?

[Francis-Nalta]

I tried to send a email with embedded links to images available on a website protected by anubis

When reciever MUA (Outlook, Thunderbird, mobile mail apps, ...) open the email, embedded images are not show.
In an standard browser, the link used in the email to the image works well.

I suppose the MUA cant execute any JS, so dont pass anubis check when tried to download the images to display.

Are they any user-agent rules for 'standard MUA' in anubis ?
Or how to allow 'standard' MUA (Outlook, Thunderbird, ...) to bypass anubis check ?
(Or last option allowing access to any to images in a some specific directory on the web server ?)

[Francis-Nalta]

After some checks with an Outlook version 2021, here is for this program the user-agent as seen by Anubis when Outlook try to get the images included (via embded links) in an email :

Mozilla/4.0 (compatible; ms-office; MSOffice 16)

As Outlook dont run any script sent in response by Anubis, the GET fail.

I have no tested others versions of Outlook, nor Thunderbird and other MUA, but i think the problem will be the same.

For now, in Anubis i will add a rule to skip challenge for this Outlook user agent

But i think such MUA programs (Outlook, Thunderbird, ...) rules should be added in Anubis distro.

Can the Anubis team explore further this MUA problem and give their opinion ?