Interesting that your security organization is worried about TLS renegotiation 
but do not mind people logging in without TLS... =)

You have

disable_plaintext_auth = no

which allows plaintext auth over non-TLS connection. See 
https://doc.dovecot.org/configuration_manual/dovecot_ssl_configuration/

"ssl=yes and disable_plaintext_auth=no: SSL/TLS is offered to the client, but 
the client isn’t required to use it. The client is allowed to login with 
plaintext authentication even when SSL/TLS isn’t enabled on the connection. 
This is insecure, because the plaintext password is exposed to the internet."

Anyways, back to the TLS renegotiation...

There is no config option in dovecot explicitly to disable this, and 
unfortunately openssl 1.0.2 does not seem to support system-wide config file to 
disable Renegotiation in ssl_conf section. With OpenSSL 1.1.1 you can actually 
edit /etc/pki/tls/openssl.cnf and disable renegotiation, without having to run 
everything on TLSv1.3.
 
For users with 1.1 you can use following to disable renegotiation in your 
distribution specific system-wide openssl.cnf:

[default_conf]
ssl_conf = ssl_sect

[ssl_sect]
system_default = system_default_sect

[system_default_sect]
Options = NoRenegotiation

Aki

> On 14/05/2022 11:13 Greg Earle <ea...@isolar.dyndns.org> wrote:
> 
>  
> On 13 May 2022, at 19:38, Elisamuel Resto <s...@samresto.dev> wrote:
> 
> > I believe this to be a configuration error, not a dovecot problem.  
> > The
> > output of dovecot -n (as an attachment; look it over for any data you 
> > do
> > not want publicized) would help to suggest changes to bring you back
> > into compliance.
> 
> Elisamuel,
> 
> I'm not really sure why you think it's a configuration error, but I'll 
> attach the "dovecot -n" output.
> 
> Thanks,
> 
>               - Greg

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