dovecot 2.4 auth: Error: sql: Invalid password in passdb: Weak password scheme 'MD5-CRYPT'

Discussion in 'Tips/Tricks/Mods' started by fireba11, Feb 5, 2026.

  1. fireba11

    fireba11 Member

    After upgrading to debian 13 and now also upgrading dovecot (held it back untill the ispconfig release :-D) mail Login failed with
    auth-worker(...)<2382351>: request [32]: Error: sql: Invalid password in passdb: Weak password scheme 'MD5-CRYPT' used and refused

    Apparently the Mail logins (yes thos might be quite old :-D) are stored in an old somewhat insecure format in the database, making dovecot 2.4 unhapy.
    Workaround is adding
    auth_allow_weak_schemes = yes
    to your dovecot config.

    Details see https://doc.dovecot.org/main/core/config/auth/schemes.html
    Since ISPconfig should not even have unencrypted passwords, i don't suppose there is a way to update storage format other than resetting all Passwords?

    Also, wanted to document the workaround for others to find :)
     
    till likes this.
  2. till

    till Super Moderator Staff Member ISPConfig Developer

    Passwords are hashed in the same way as the passwords in /etc/passwd are encrypted, so we can not update the format. The only way is to re-enter the password so it can be encrypted using the current encryption format.
     
    ahrasis likes this.
  3. SpeedyB

    SpeedyB Member HowtoForge Supporter

    @till hsve you seen this?
    https://doc.dovecot.org/main/howto/convert_password_schemes.html

    Is there an easy way to implement this with ispconfig?

    I have the same issue and simply updating the password is a nightmare since I have a lot of very old mailboxes and no other way to contact the people to change it, and they just don’t seem to do it themselves :(

    Apparently the scheme has changed over time where MD5-CRYPT was used by default and this has now changed and with 2.4.0 this has been disabled by default now: https://doc.dovecot.org/2.4.2/core/config/auth/schemes.html#md5-crypt
    I see the new mailboxes have $6$round:5000 as start and old have just $1$ in the database and those are a lot :(
     
  4. SpeedyB

    SpeedyB Member HowtoForge Supporter

  5. till

    till Super Moderator Staff Member ISPConfig Developer

    This should probably work on an ISPConfig system as well. Your script to update the password should either use the ISPConfig API for the password update or update it directly in MySQL.
     

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