Passwords are hidden in logs, mostly. Debug logging unfortunately can leak some password information.
So why not just get rid of this attack vector? Who needs users' plaintext passwords in debug logs anyway? I can't think of a situation when this is necessary. But that's just me of course.
Turn on auth_debug=yes and see, you'll see passwords being masked.
I have this value set to yes already and the passwords are not being masked. Perhaps you meant auth_debug_passwords = no?
Use hex encoding, base64 encoding or hashing the password, as it says. E.g. %{sha256,salt=%{user}:password}. Directly using user's password for mail crypt keys is unsafe anyways, due to % being an expansion character.
Will this work in doveadm commands? Or it has to be done in a PHP script feeding login data to dovecot (like webmail/frontend)? Will it prevent passwords from showing in the logs?
On 2022-10-09 14:02, Aki Tuomi wrote:
On 09/10/2022 12:53 EEST Serveria Support <support@serveria.com> wrote:
Sometimes not. If the data stored in mail accounts is more valuable than the server and control over it.
So this means passwords cannot be masked/hidden in the logs?
Passwords are hidden in logs, mostly. Debug logging unfortunately can leak some password information.
You realize that it actually defeats the whole idea of encrypted storage? It's useless.
Dovecot mail crypt plugin is primarily intended for securing storage, especially one that is remote, like NFS or object storage. It is not intended for securing your server against malicious admins.
In production use, customers usually use a site-wide global keypair to encrypt the information stored in non-local storage.
I can think of lots of scenarios: malicious system administrator reading users mails and blackmailing them or selling their business secrets to competitors, corrupt law enforcement in some countries getting rid of political or business opponents by disclosing the contents of their mails and I can go on and on and on...
Yes, and mail crypt plugin is not intended for protecting these cases.
There is no such thing as semi-privacy. Privacy is either there or it's not.
What exactly Dovecot does to hide passwords in logs?
Turn on auth_debug=yes and see, you'll see passwords being masked.
I've studied mail-crypt plugin's docs and it's written there:
Also, it might be visible in debug logging. Suggested approaches are base64 encoding, hex encoding or hashing the password. With hashing, you get the extra benefit that password won’t be directly visible in logs.
So how can I make passwords to be not directly visible in logs?
Aki
Use hex encoding, base64 encoding or hashing the password, as it says. E.g. %{sha256,salt=%{user}:password}. Directly using user's password for mail crypt keys is unsafe anyways, due to % being an expansion character.
On 2022-10-09 11:39, Aki Tuomi wrote:
If you have intruder that is able to enable logs for your server, then you have bigger issues than someone enabling logs to see passwords.
Dovecot does it's best to hide passwords in logs, but unfortuntely this isn't perfect.
Aki
On 08/10/2022 23:49 EEST Serveria Support <support@serveria.com> wrote:
Hi,
I'm here with a follow-up. I have managed to fix this issue!
I have rebuilt the entire project from scratch, using vanilla versions of Dovecot, Postfix, SOGO webmail etc and everything works as expected: emails are getting encrypted, I'm able to send, receive and read emails in webmail. I suspect the root of the issue was that I was using software package called iredmail. My guess is that all the master admin drama was caused by iredmail. Big thanks to you guys for the hints and ideas which eventually helped me troubleshoot this issue! I appreciate your assistance.
P.S. Btw, is there any way to hide plain text passwords from Dovecot log files? Disabling auth debugging won't help as the system may get compromised and the intruder can re-enable logs and grab the passwords from the logs. The only person who should know/see the password in clear text should be the respective mail user. Is there any way to achieve this?
On 2022-09-15 08:16, Aki Tuomi wrote:
On 14/09/2022 19:34 EEST Serveria Support <support@serveria.com> wrote:
Thanks for your help. Do you know in which folder the keys are stored? I'd like to check the permissions...
Some notes here, after reading this thread again:
Keys are stored in mail_attributes file, which depends on your config, but usually is %h/dovecot-attributes, which means it'll be in user's home directory.
The key format is Dovecot Dcrypt Key, you can use
doveadm mailbox cryptokey exportto export them in PEM format. Only **global keys** expect PEM formatted keys, which you are not using.If you are using mail_crypt_private_password to encrypt the user key, you will need to provide this every time you want to access the user's emails, including using doveadm. Dovecot does not know what password you are using.
Your logs indicate that you are, still, using master userdb. This will not work. You cannot use master users with per-user encryption passwords in the way you do. If you want to use master users / master password, you must not encrypt the user key.
You should really focus on reading your logs, because they really do indicate that the userdb_mail_crypt_private_password is not exprted in anywhere, so clearly and obviously you are not able to access the mails.
Maybe consider removing the master user authentication completely?
Aki