Disable folder creation for details username

Robert Blayzor rblayzor.bulk at inoc.net
Fri Mar 17 12:23:48 UTC 2023

This may be more of a CPanel issue than Dovecot but CPanel uses Dovecot 
and not sure if this is a knob we have available in Dovecot or we need 
to reach out to Cpanel directly to see if this is some custom code they 
added to their distros.

Anyway, W/R/T emails sent with dtails/ + addresses ie:

foo+bar at mydomain.com

And with LDA/LMTP, in Cpanel by default the detials part, in this case 
"bar" will be created in it's own folder. Automatically.  To us, this 
can be an attack vector/DOS from a malicious actor so we want to turn it 

We understand there is:

Which we have yes, as we do want to create mailboxes automatically when 
the first message comes in, but not these folders.

I don't know if this folder autocreation on detail part is a Dovecot 
thing, or specific to Cpanel. It appears CPanel has a patch/code to 
option to turn it off, but it's only on a per mailbox basis. We want to 
turn this behavior off globally.

As far as I know, CPanel doesn't release whatever patches they made to 
make this happen, asking here if anyone has experience with this before 
we start chasing them for answers.

XMPP: rblayzor.AT.inoc.net
PGP:  https://pgp.inoc.net/rblayzor/

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