> On August 5, 2016 at 6:47 PM "Michael A. Peters" <mpeters at domblogger.net> wrote: > > > On 08/05/2016 08:41 AM, Robert Blayzor wrote: > > Is there a way to configure Dovecot to perhaps filter/enforce which passwords are accepted before authenticating? > > > > Ie: Reject immediately (without a database lookup) if password is not X characters in length? > > > > ? > > > > Not sure what the benefit would be, other than helping automated bots > figure out your minimum password length based upon the response time.The response time will be same anyways. Anyways. It is better to enforce this kind of thing when users define the password than during login. Aki
On Aug 5, 2016, at 12:12 PM, Aki Tuomi <aki.tuomi at dovecot.fi> wrote:> > The response time will be same anyways. > > Anyways. It is better to enforce this kind of thing when users define the password than during login.The idea would be to mitigate unnecessary database dips for password that don?t clearly pass said password policy. Sure you can enforce what passwords users use; but you can?t enforce what is being attempted to authenticate. A lot of ?bots? try very simple passwords say less than X characters; over and over and over again before they give up. I realize Dovecot mitigates this by slowing them down; but always nice to have another optional layer of defense to clip this kind of garbage closer to the door. At the very least have a reject empty password option. -- Robert inoc.net!rblayzor XMPP: rblayzor.AT.inoc.net PGP Key: 78BEDCE1 @ pgp.mit.edu
> On August 5, 2016 at 9:10 PM Robert Blayzor <rblayzor.bulk at inoc.net> wrote: > > > On Aug 5, 2016, at 12:12 PM, Aki Tuomi <aki.tuomi at dovecot.fi> wrote: > > > > The response time will be same anyways. > > > > Anyways. It is better to enforce this kind of thing when users define the password than during login. > > > The idea would be to mitigate unnecessary database dips for password that don?t clearly pass said password policy. Sure you can enforce what passwords users use; but you can?t enforce what is being attempted to authenticate. A lot of ?bots? try very simple passwords say less than X characters; over and over and over again before they give up. > > I realize Dovecot mitigates this by slowing them down; but always nice to have another optional layer of defense to clip this kind of garbage closer to the door. > > At the very least have a reject empty password option. > > -- > Robert > inoc.net!rblayzor > XMPP: rblayzor.AT.inoc.net > PGP Key: 78BEDCE1 @ pgp.mit.eduI would like to mention the new auth policy server support. It works with weakforced. See http://wiki2.dovecot.org/Authentication/Policy And https://github.com/PowerDNS/weakforced Correct usage should help you more than your plan, I promise. Aki
> A lot of ?bots? try very simple passwords say less than X > characters; over and over and over again before they give up. > > I realize Dovecot mitigates this by slowing them down; but always nice to > have another optional layer of defense to clip this kind of garbage closer > to the door.Check out fail2ban. It's very useful for that sort of repeated bot attack. Michael