I'm trying to find out how to remove non-whitelisted attachments (by mime type) (f.e. zip, exe, ...) and append a message about the removed attachments.
I found this: https://superuser.com/a/1502589
And it worked to add a message to the subject.
But I cannot find out how to add a message to the body.
My plan was to use a regex on the attachment mime types and allow f.e.
text/*
and application/json
etc.
But I cannot find a single example how to change the body.
I'm using mailcow and sieve script (which I'm both new to).
Or is there a better way to "sanitize" emails before the get put into the inbox?
EDIT (2023-02-07) : I found this today:
Extension foreverypart
.
Sieve Email Filtering: MIME Part Tests, Iteration, Extraction, Replacement, and Enclosure
https://www.rfc-editor.org/rfc/rfc5703.html \
The "replace" command is defined to allow a MIME part to be replaced with the text supplied in the command.
Exactly what I try to do.
Now I need to find out how to install the extension and try it out.