- dovecot - dovecot.org

Avoiding POODLE vulnerability
by Steve Litt 20 Nov '23

20 Nov '23

Hi all, Ten years after the fact I learned about POODLE (Padding Oracle On Downgraded Legacy Encryption) vulnerabilities, which enable a poorly configured server to force my client to downgrade to vulnerable encryption. My current conf.d/10-ssl.conf contains the following line: ssl_cipher_list = ALL:!LOW:!SSLv3:!EXP:!aNULL I've read that I should change the preceding line to the following: ssl_protocols = !SSLv3 !SSLv2 Is this correct? For some reason I have the same ssl_cipher_list in dovecot.conf. Should I make the change there too? Is there anything else I need to change? The following is my current dovecot.conf: ================================================= # 2.3.13 (89f716dc2): /etc/dovecot/dovecot.conf # OS: Linux 5.10.12_1 x86_64 # Hostname: mydesk.domain.cxm mail_location = maildir:~/mail/Maildir:INBOX=~/mail/Maildir/.INBOX namespace inbox { inbox = yes location = prefix = } passdb { driver = pam args = %s } userdb { driver = passwd } protocols = imap service imap-login { inet_listener imap { #port = 143 port = 0 } inet_listener imaps { port = 993 #port = 0 ssl = yes #ssl = no } } ssl = required #ssl = yes ssl_cert = </etc/ssl/dovecot_certs/certs/dovecot.pem ssl_cipher_list = ALL:!LOW:!SSLv3:!EXP:!aNULL ssl_key = </etc/ssl/dovecot_certs/private/dovecot.pem ================================================= By the way, does the preceding dovecot.conf even use the files in directories off conf.d ? Thanks, SteveT Steve Litt Autumn 2023 featured book: Rapid Learning for the 21st Century http://www.troubleshooters.com/rl21

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passdb doesn't support credential lookups
by Michael Grant 20 Nov '23

20 Nov '23

I'm having trouble authenticating certain users. I see this in the logs: Nov 19 16:26:40 auth: Debug: pam(jane,192.168.2.83,<...>): Performing passdb lookup Nov 19 16:26:40 auth: Debug: pam(jane,192.168.2.83,<...>): passdb doesn't support credential lookups Nov 19 16:26:40 auth: Debug: pam(jane,192.168.2.83,<...>): Finished passdb lookup at the command line, if I run this: % doveadm auth login jane Password: passdb: jane auth succeeded Oddly, I have a handfull of users that are failing and others that are not and I don't see the difference.

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Re: DMARC Failures for Mailing List
by dovecot＠x9p.org 18 Nov '23

18 Nov '23

On 11/17/23 10:38, Nick Lockheart wrote: > The DKIM check is also failing. I think the list software may be re-writing the > message bodies. I believe one of the reasons for the DKIM failure is this addition/configuration by mailman in the footer of every message (the unsubscribe stuff): >>>>>>>> _______________________________________________ dovecot mailing list --dovecot(a)dovecot.org To unsubscribe send an email todovecot-leave(a)dovecot.org >>>>>>>> --x9p On 11/17/23 10:38, Nick Lockheart wrote: The DKIM check is also failing. I think the list software may be re- writing the message bodies. I believe one of the reasons for the DKIM failure is this addition/ configuration by mailman in the footer of every message (the unsubscribe stuff): >>>>>>>> _______________________________________________ dovecot mailing list -- dovecot(a)dovecot.org To unsubscribe send an email to dovecot-leave(a)dovecot.org >>>>>>>> --x9p

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DMARC Failures for Mailing List
by Nick Lockheart 18 Nov '23

18 Nov '23

Now that we've got our new mail server going and the DMARC reports are coming in, I'm finding a lot of DMARC failures for messages that I'm sending to this list. It seems that when I send a message to this list, the list software forwards it to other people on my behalf, but uses my email address in the header_from. This results in an SPF failure, because SPF only allows our MX to send mail for our domain. The DKIM check is also failing. I think the list software may be re- writing the message bodies. Another user that I replied to on this list a day ago said my list mail went to spam on his gmail. 1. Will our domain reputation be harmed by having a lot of copies of the same messages going to a bunch of different people on different ISPs and all of them failing DMARC? It seems that some places are using databases that look for duplicate content sent to multiple recipients to identify bulk mail and spam. 2. Is there any way to mitigate DMARC issues for mailing lists? It seems like the mailing list software should be sending out the emails as itself, not as the user that submitted the message. Now that we've got our new mail server going and the DMARC reports are coming in, I'm finding a lot of DMARC failures for messages that I'm sending to this list. It seems that when I send a message to this list, the list software forwards it to other people on my behalf, but uses my email address in the header_from. This results in an SPF failure, because SPF only allows our MX to send mail for our domain. The DKIM check is also failing. I think the list software may be re-writing the message bodies. Another user that I replied to on this list a day ago said my list mail went to spam on his gmail. 1. Will our domain reputation be harmed by having a lot of copies of the same messages going to a bunch of different people on different ISPs and all of them failing DMARC? It seems that some places are using databases that look for duplicate content sent to multiple recipients to identify bulk mail and spam. 2. Is there any way to mitigate DMARC issues for mailing lists? It seems like the mailing list software should be sending out the emails as itself, not as the user that submitted the message.

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how to filter in doevecot/lmtp with sieve according to postfix orig_to value
by TSHIMANGA Minkoka 17 Nov '23

17 Nov '23

Dear All, I am managing an email infrastructure running with the below. Rocky Linux 8.7 (Green Obsidian) 4.18.0-425.3.1.el8.x86_64 postfix-3.5.8-4.el8.x86_64 dovecot-2.3.16-3.el8.x86_64 dovecot-pigeonhole-2.3.16-3.el8.x86_64 In reality there are more packages installed and configured. But I limited my enumeration above to what I think is relevant. I will be happy to provide more details if needed and/or requested. Here is my problem, or at least on what I need help/guidance/assistance. I have a virtual alias that forward emails to support(a)example.com to my inbox tshimanga.minkoka(a)example.com. That works fine as I can see those emails in my INBOX. And I want those emails to be moved in INBOX/support with a local sieve rule. For that I have the below that works. # rule:[support] if allof (header :is "to" "support(a)example.com") { fileinto :create "INBOX/support"; } The problem is that the above sieve rule seems not enough to catch email where support(a)example.com is not the "To" fields, as with cases of "Cc:" or "Bcc:". In the log of postfix, I can see lines with "... postfix/lmtp ... orig_to=<support(a)example.com> ...". The problem I am facing is that "orig_to" is not part of the headers postfix/lmtp (in reality dovecot/lmtp process) can see in order to apply on it a sieve rule. Any suggestions on how I can also sieve filter those emails ? Regards, Tshimanga

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auth service over tls
by ibra 17 Nov '23

17 Nov '23

Hi, I'm trying running tls connections for both auth and lmtp services. For lmtp it is ok, for auth service I couldnt make it. I configure dovecot with the next configuration in file "conf.d/10-myconfig.conf": service auth { inet_listener { name = dovecot_auth address = 127.0.0.1 port = 12345 ssl = yes } user = mail # I've also tried with different users and without set it as well. } service lmtp { inet_listener { name = dovecot_lmtp address = 127.0.0.1 port = 24 ssl = yes } } Is something else I'm missing? Hi, I'm trying running tls connections for both auth and lmtp services. For lmtp it is ok, for auth service I couldnt make it. I configure dovecot with the next configuration in file "conf.d/10-myconfig.conf": service auth { inet_listener { name = dovecot_auth address = 127.0.0.1 port = 12345 ssl = yes } user = mail # I've also tried with different users and without set it as well. } service lmtp { inet_listener { name = dovecot_lmtp address = 127.0.0.1 port = 24 ssl = yes } } Is something else I'm missing?

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Re: Anyone Watching Actvity from this network? Attempting Dovecot Buffer Overflows?
by Joseph Tam 16 Nov '23

16 Nov '23

On Wed, 15 Nov 2023, 23:25 Michael Peddemors, <michael(a)linuxmagic.com> wrote: > Not sure yet if it is Dovecot, or the SSL libraries they are > attempting > to break, but using a variety of SSL/TLS methods and connections... > > They are not interested in dovecot per se. They scan for TLS vulnerabilities, > mostly. They're running comprehensive port scans, so they're targeting more than just SSL services. > OrgName: Academy of Internet Research Limited Liability > Company > OrgId: AIRLL > Address: #A1- 5436 > Address: 1110 Nuuanu Ave > City: Honolulu > StateProv: HI > PostalCode: 96817 > Country: US Out of business virtual offices, naturally. AIRLL also operating out of 195.96.137.0/24. Joseph Tam <jtam.home(a)gmail.com>

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Re: auth service over tls
by ibra 16 Nov '23

16 Nov '23

I was testing a bit this setup of putting them in different servers, since these options are implemented. What I was not sure was if they support TLS as well. So Postfix-Dovecot SASL AUTH is not supported. Is TLS LMTP supported between Postfix and Dovecot? I see that Dovecot LMTP supports a TLS connection, but not sure if Postfix can make the TLS initial request. I just could exchange data over LMTP in plain (no TLS) between Postfix and Dovecot. Regards, Ibra On Thu, 16 Nov 2023 at 12:28, Nick Lockheart <forum(a)ageofdream.com> wrote: > > Are Postfix and Dovecot running on the same server? If so, you might be > better served by connecting with a UNIX socket rather than TCP. > > I'm not sure there is much security benefit to using TLS on the loopback > interface which is what was in your example from the previous email. > > And to clarify, Postfix supports TLS for authentication between an email > program like Thunderbird and the Postfix server, but does not support TLS > for the SASL AUTH *service* connection from Postfix to the AUTH provider > (Dovecot or Cyrus-SASL). > > Also, please use the group reply function so your email goes to the list, > this email only went to me. > > > On Thu, 2023-11-16 at 09:38 +0000, ibra wrote: > > Good Morning, > thank you for your fast response, and sorry to not answer before, I forgot > to check spam folder. Good to know that postfix does not support SASL AUTH > over TLS, because actually I was planning to use it. > I started with Dovecot to check if auth port support tls. For that I > launched tls handshake using openssl, like this command: > $ openssl s_client -servername mail.sample.com -connect localhost:12345 > > But I got an error. (In summary Dovecot ends the connection). > Anyway, it would be awesome that in the future both Postfix and Dovecot > could support it. > > > On LMTP port, tls handshake worked in Dovecot side, now I have to > configure Postfix to make the request to dovecot LMTP over tls. > > With Postfix I was able to send data to Dovecot LMTP port, but was not > over TLS. Do you know what settings should I enable in Postfix side? > > Regards > Ibra. > > > On Wed, 15 Nov 2023 at 11:08, Nick Lockheart <nlockheart(a)ageofdream.com> > wrote: > > On Wed, 2023-11-15 at 10:00 +0000, ibra wrote: > > Hi, > I'm trying running tls connections for both auth and lmtp services. For > lmtp it is ok, for auth service I couldnt make it. I configure dovecot with > the next configuration in file "conf.d/10-myconfig.conf": > > > Which MTA are you trying to connect from? Postfix does not support SASL > AUTH over TLS, for example. > > > I was testing a bit this setup of putting them in different servers, since these options are implemented. What I was not sure was if they support TLS as well. So Postfix-Dovecot SASL AUTH is not supported. Is TLS LMTP supported between Postfix and Dovecot? I see that Dovecot LMTP supports a TLS connection, but not sure if Postfix can make the TLS initial request. I just could exchange data over LMTP in plain (no TLS) between Postfix and Dovecot. Regards, Ibra On Thu, 16 Nov 2023 at 12:28, Nick Lockheart <forum(a)ageofdream.com> wrote: Are Postfix and Dovecot running on the same server? If so, you might be better served by connecting with a UNIX socket rather than TCP. I'm not sure there is much security benefit to using TLS on the loopback interface which is what was in your example from the previous email. And to clarify, Postfix supports TLS for authentication between an email program like Thunderbird and the Postfix server, but does not support TLS for the SASL AUTH *service* connection from Postfix to the AUTH provider (Dovecot or Cyrus-SASL). Also, please use the group reply function so your email goes to the list, this email only went to me. On Thu, 2023-11-16 at 09:38 +0000, ibra wrote: Good Morning, thank you for your fast response, and sorry to not answer before, I forgot to check spam folder. Good to know that postfix does not support SASL AUTH over TLS, because actually I was planning to use it. I started with Dovecot to check if auth port support tls. For that I launched tls handshake using openssl, like this command: $ openssl s_client -servername mail.sample.com -connect localhost:12345 But I got an error. (In summary Dovecot ends the connection). Anyway, it would be awesome that in the future both Postfix and Dovecot could support it. On LMTP port, tls handshake worked in Dovecot side, now I have to configure Postfix to make the request to dovecot LMTP over tls. With Postfix I was able to send data to Dovecot LMTP port, but was not over TLS. Do you know what settings should I enable in Postfix side? Regards Ibra. On Wed, 15 Nov 2023 at 11:08, Nick Lockheart <nlockheart(a)ageofdream.com> wrote: On Wed, 2023-11-15 at 10:00 +0000, ibra wrote: Hi, I'm trying running tls connections for both auth and lmtp services. For lmtp it is ok, for auth service I couldnt make it. I configure dovecot with the next configuration in file "conf.d/ 10-myconfig.conf": Which MTA are you trying to connect from? Postfix does not support SASL AUTH over TLS, for example.

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Fwd: dovecot submission max line length
by Kees van Vloten 14 Nov '23

14 Nov '23

Op 14-11-2023 om 14:35 schreef Aki Tuomi: >> On 14/11/2023 14:59 EET Kees van Vloten <keesvanvloten(a)gmail.com> wrote: >> >> Hi all, >> >> >> After upgrading Debian Bullseye (Dovecot 2.3.13) to Bookworm (Dovcecot >> 2.3.19), submission-login returns an error on Kerberos authentication: >> "Client sent invalid command: Command line is too long". >> >> When I initially set this up on Bullseye I have seen the same issue, but >> adding "imap_max_line_length = 2M" solved it. >> >> Now with 2.3.19 kerberos authentication still works (with this setting) >> for imap connections but it stopped working for submission. >> >> Is there a new config setting for submission-login that I missed? Or is >> this a bug in 2.3.19? >> >> >> - Kees. >> >> > You are probably running into a client-side issue. SMTP RFC says that > all commands, including sasl ir, must be at most 998 bytes. Can you > check if the client is sending AUTH KERBEROS which is longer than 998 > lines? > > After AUTH KERBEROS you can send longer lines. The client has not changed. I have just upgraded the server from Bullseye to Bookworm, without configuration changes to Dovecot. The only change is version 2.3.13 to 2.3.19, that is why my first suspicion is that something changed in dovecot submission-login. The client is Thunderbird 102 and that has not changed for a long time (a year or so). Is there a way to create debug logs that show the client communication to submission-login? I had enabled "auth_debug" and "auth_verbose" in Dovecot but that seems to log the server side communication only (see below). And even with that information, would it be possible to convince Thunderbird to send 'AUTH KERBEROS' if it does not do that already? I logging I have is this: Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Sent: 220 mailserver.example.com Dovecot ready. Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Sending replies Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: No more commands pending Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Received new command: EHLO [192.168.1.106] Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: New command Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Execute command Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Pipeline blocked Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: 250 reply: Submitted Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Replied Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Ready to reply Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Trigger output Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Next to reply Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Sending replies Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Next to reply Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Completed Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Pipeline unblocked Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Connection state reset Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: 250 reply: Sent: 250-mailserver.example.com 8BITMIME AUTH GSSAPI GSS-SPNEGO PLAIN BURL imap CHUNKING ENHANCEDSTATUSCODES SIZE PIPELINING Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Finished Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: Destroy Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command EHLO: 250 reply: Destroy Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Trigger output Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: No more commands pending Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Sending replies Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: No more commands pending Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Client sent invalid command: Command line is too long Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: Invalid command Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: 500 reply: Submitted Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: Replied Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: Ready to reply Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Trigger output Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Sending replies Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: Next to reply Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: Completed Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: 500 reply: Sent: 500 5.5.2 Line too long Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: Finished Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: Destroy Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: command [unknown]: 500 reply: Destroy Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Trigger output Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: No more commands pending Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Sending replies Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: No more commands pending Nov 14 13:44:37 mailserver dovecot: submission-login: Debug: smtp-server: Remote closed connection: Connection closed Do note that I redacted a column with the server ipaddress to make the lines a bit shorter and more readable. - Kees > > Aki

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MySQL connection keepalive for pass/auth db
by dvuoud＠at.encryp.ch 14 Nov '23

14 Nov '23

Hello, Is it possible to configure SQL connection keepalive for Dovecot? Probably what I have to do is "Note that the SQL backend must be used via Proxy", however I was unsucsessful in figuring out how can I setup this to get use of connection pool at Dovecot. Thanks. > $ dovecot --version > 2.3.20 (80a5ac675d) > $ dovecot -n > # 2.3.20 (80a5ac675d): /etc/dovecot/dovecot.conf > # Pigeonhole version 0.5.20 (149edcf2) > # OS: Linux 6.1.57 x86_64 Gentoo Base System release 2.14 > # Hostname: flopster > import_environment = TZ CORE_OUTOFMEM CORE_ERROR TZ=:/etc/localtime > lmtp_add_received_header = no > mail_gid = vmail > mail_location = maildir:~/.maildir > mail_server_admin = mailto:me@at.encryp.ch > mail_uid = vmail > managesieve_notify_capability = mailto > managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date index ihave duplicate mime foreverypart extracttext editheader > metric auth_failures { > filter = event=auth_request_finished AND NOT success=yes > } > metric auth_success { > filter = event=auth_request_finished AND success=yes > } > metric imap_command { > filter = event=imap_command_finished > group_by = cmd_name tagged_reply_state > } > metric mail_delivery { > filter = event=mail_delivery_finished > group_by = duration:exponential:1:5:10 > } > metric smtp_command { > filter = event=smtp_server_command_finished > group_by = cmd_name status_code duration:exponential:1:5:10 > } > namespace inbox { > inbox = yes > location = > mailbox Drafts { > special_use = \Drafts > } > mailbox Junk { > special_use = \Junk > } > mailbox Sent { > special_use = \Sent > } > mailbox "Sent Messages" { > special_use = \Sent > } > mailbox Trash { > special_use = \Trash > } > prefix = > } > passdb { > args = * > driver = pam > } > passdb { > args = /etc/dovecot/dovecot-sql.conf.ext > driver = sql > } > plugin { > sieve = file:~/sieve;active=~/.dovecot.sieve > sieve_extensions = +editheader > } > protocols = imap lmtp sieve > service auth { > unix_listener /var/spool/postfix/private/auth { > group = postfix > mode = 0660 > user = postfix > } > vsz_limit = 2 G > } > service dict { > unix_listener dict-passdb { > mode = 0600 > user = vmail > } > unix_listener dict-userdb { > mode = 0600 > user = vmail > } > } > service lmtp { > unix_listener /var/spool/postfix/private/dovecot-lmtp { > group = postfix > mode = 0600 > user = postfix > } > } > service managesieve-login { > inet_listener sieve { > port = 4190 > } > } > service stats { > inet_listener http { > address = [::] > port = 9900 > } > } > ssl = required > ssl_cert = </etc/ssl/dovecot/server.crt > ssl_dh = # hidden, use -P to show it > ssl_key = # hidden, use -P to show it > userdb { > driver = passwd > } > userdb { > args = /etc/dovecot/dovecot-sql.conf.ext > driver = sql > } > protocol lmtp { > mail_plugins = " sieve" > postmaster_address = postmaster(a)at.encryp.ch > } > protocol lda { > mail_plugins = sieve > } > local_name flopster.at.encryp.ch { > ssl_cert = </etc/ssl/domains/flopster.at.encryp.ch/fullchain > ssl_key = # hidden, use -P to show it > }

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