Посмотрел свою древнюю инсталляцию web-cyradm, таблица accountuser там выглядит вот так:

mysql> select * from accountuser;
+-----------+---------------+--------+-------------+
| username  | password      | prefix | domain_name |
+-----------+---------------+--------+-------------+
| cyrus     | vjD5UKrOWumxs |        |             |
| xxxx0002 | 95LtBJGNVP9wc | xxxx  | x.ru    |
| xxxx0001 | cfS0NnZc/dezU | xxxx  | x.ru    |
| xxxx0005 | 82mRPY2JJo6r6 | xxxx  | x.ru    |
| xxxx0004 | 0aZQ4HovNwio2 | xxxx  | x.ru    |
+-----------+---------------+--------+-------------+
5 rows in set (0.06 sec

Юзеры заводились средствами web-cyradm.

На всякий случай:

# cat /etc/pam.d/imap
#%PAM-1.0
#auth     include       system-auth
#account  include       system-auth

auth sufficient pam_mysql.so user=mail passwd=xxxxxx  host=localhost db=mail table=accountuser usercolumn=username passwdcolumn=password crypt=1 logtable=log logmsgcolumn=msg logusercolumn=user loghostcolumn=host logpidcolumn=pid logtimecolumn=time

#auth sufficient pam_unix_auth.so

account required pam_mysql.so user=mail passwd=xxxxx host=localhost db=mail table=accountuser usercolumn=username passwdcolumn=password crypt=1 logtable=log logmsgcolumn=msg logusercolumn=user loghostcolumn=host logpidcolumn=pid logtimecolumn=time

#account  sufficient       pam_unix_acct.so

-- 
vvk

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