June 2021 - dovecot - dovecot.org

ssl_min_protocol v2.3.15
by Theo Pannen 23 Jun '21

23 Jun '21

Hello, it seems that the default value for ssl_min_protocol has changed from TLSv1 to TLSv1.2, right? After upgrading to v2.3.15 and with ssl_min_protocol commented out, the server no longer offers TLSv1 and TLSv1.1. This is a good idea, but should be documented. Theo

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CVE-2021-33515: SMTP Submission service STARTTLS injection
by Timo Sirainen 22 Jun '21

22 Jun '21

Open-Xchange Security Advisory 2021-06-21 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-4583 (Bug ID) Vulnerability type: CWE-74: Failure to Sanitize Data into a Different Plane ('Injection') Vulnerable version: 2.3.0-2.3.14 Vulnerable component: submission Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.14.1 Vendor notification: 2021-05-21 Solution date: 2021-05-22 Public disclosure: 2021-06-21 CVE reference: CVE-2021-33515 CVSS: 4.2 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N) Researcher credit: Fabian Ising and Damian Poddebniak of Münster University of Applied Sciences Vulnerability Details: On-path attacker could inject plaintext commands before STARTTLS negotiation that would be executed after STARTTLS finished with the client. Only the SMTP submission service is affected. Risk: Attacker can potentially steal user credentials and mails. The attacker needs to have sending permissions on the submission server (a valid username and password). Workaround: None. Solution: Operators should update to 2.3.14.1 or later version.

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Dovecot deliver and imap process hangs
by Rok Saksida 22 Jun '21

22 Jun '21

Hello. Dovecot version: 2.2.36 OS: CentOS Linux release 7.9.2009 (Core) Kernel: 3.10.0-1160.11.1.el7.x86_64 I have two dovecot servers in replication master/master. Sometimes happens that deliver or imap process hangs and causing high CPU usage. In log's I only see locking failures but not initial cause why this happened. For mail storage I use ZFS pool with compression enabled. I made some digging and find this option: mmap_disable = yes. I will try this setting today evening. But I wondering if you have any idea why this happening and how to start solving this problems? Is there any additional setting like mmap_disable that can help solved this issues? -- BR

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Upgrade path
by Andrea Gabellini 22 Jun '21

22 Jun '21

Hello, I have a configuration with two proxy/director and two backend with replication. All at version 2.3.10.1. What is the suggested upgrade path to 2.3.15? I think to switch traffic to only one proxy and one backend and upgrade the two servers that remain without traffic. Then I switch the traffic to these upgraded servers and proceed with the upgrade of the others two. Is this correct? Or is best to upgrade first the two proxy/director and next the two backend? Thanks, Andrea -- __________________________ Business is like riding a bicycle. Either you keep moving or you fall down. __________________________ TIM San Marino S.p.A. Andrea Gabellini Engineering R&D TIM San Marino S.p.A. - https://www.telecomitalia.sm Via Ventotto Luglio, 212 - Piano -2 47893 - Borgo Maggiore - Republic of San Marino Tel: (+378) 0549 886237 Fax: (+378) 0549 886188 -- Informativa Privacy Questa email ha per destinatari dei contatti presenti negli archivi di TIM San Marino S.p.A.. Tutte le informazioni vengono trattate e tutelate nel rispetto della normativa vigente sulla protezione dei dati personali (Reg. EU 2016/679). Per richiedere informazioni e/o variazioni e/o la cancellazione dei vostri dati presenti nei nostri archivi potete inviare una email a privacy(a)telecomitalia.sm. Avviso di Riservatezza Il contenuto di questa e-mail e degli eventuali allegati e' strettamente confidenziale e destinato alla/e persona/e a cui e' indirizzato. Se avete ricevuto per errore questa e-mail, vi preghiamo di segnalarcelo immediatamente e di cancellarla dal vostro computer. E' fatto divieto di copiare e divulgare il contenuto di questa e-mail. Ogni utilizzo abusivo delle informazioni qui contenute da parte di persone terze o comunque non indicate nella presente e-mail potra' essere perseguito ai sensi di legge.

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CVE-2021-29157: oauth2 JWT local validation path traversal
by Timo Sirainen 21 Jun '21

21 Jun '21

Open-Xchange Security Advisory 2021-06-21 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-4476 (Bug ID) Vulnerability type: CWE-24: Path Traversal: '../filedir' Vulnerable version: 2.3.11-2.3.14 Vulnerable component: imap, pop3, submission, managesieve Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.14.1 Vendor notification: 2021-03-22 Solution date: 2021-04-14 Public disclosure: 2021-06-21 CVE reference: CVE-2021-29157 CVSS: 6.7 (CVSS3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) Researcher credit: Kirin of Tencent Security Xuanwu Lab Vulnerability Details: Dovecot does not correctly escape kid and azp fields in JWT tokens. This may be used to supply attacker controlled keys to validate tokens in some configurations. This requires attacker to be able to write files to local disk. Risk: Local attacker can login as any user and access their emails. Workaround: Disable local JWT validation in oauth2, or use a different dict driver than fs:posix. Solution: Operators should update to 2.3.14.1 or later version.

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CVE-2020-28200: Sieve excessive resource usage
by Timo Sirainen 21 Jun '21

21 Jun '21

Open-Xchange Security Advisory 2021-06-21 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-4159 (Bug ID) Vulnerability type: CWE-400 Vulnerable version: 1.2.0-2.3.14 Vulnerable component: lmtp, lda Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.15 Vendor notification: 2020-09-23 Solution date: 2020-12-07 Public disclosure: 2021-06-21 CVE reference: CVE-2020-28200 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Researcher credit: Innokentii Sennovskii from BI.ZONE Vulnerability Details: Sieve interpreter is not protected against abusive scripts that claim excessive resource usage. Especially scripts using massive amounts of regexps. Risk: Attacker can DoS the mail delivery system by using excessive amount of CPU and/or reaching the lmtp/lda process limits. Workaround: Disabling the regex sieve extension avoids the worst problems. lmtp_user_concurrency_limit may also be helpful. Solution: Operators should update to 2.3.15 or later version.

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Pigeonhole v0.5.15 released
by Timo Sirainen 21 Jun '21

21 Jun '21

Hi, Pigeonhole release for Dovecot v2.3.15. One thing we noticed a bit before release is that if you're using imap_sieve_filter plugin, the IMAP FILTER command may trigger the new excessive resource usage check since it can be processing many messages rapidly. You may want to prevent this with protocol imap { sieve_max_cpu_time=0 } https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.15.t… <https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.15.t…> https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.15.t… <https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.15.t…> Binary packages in https://repo.dovecot.org/ <https://repo.dovecot.org/> Docker images in https://hub.docker.com/r/dovecot/dovecot <https://hub.docker.com/r/dovecot/dovecot> * CVE-2020-28200: Sieve interpreter is not protected against abusive scripts that claim excessive resource usage. Fixed by limiting the user CPU time per single script execution and cumulatively over several script runs within a configurable timeout period. Sufficiently large CPU time usage is summed in the Sieve script binary and execution is blocked when the sum exceeds the limit within that time. The block is lifted when the script is updated after the resource usage times out. * Disconnection log messages are now more standardized across services. They also always now start with "Disconnected" prefix. - managesieve: Commands pipelined together with and just after the authenticate command cause these commands to be executed twice.

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error: "The certificate is empty"
by A. Schulze 18 Jun '21

18 Jun '21

Hello, on a farm of multiple identical dovecot servers I start seeing this error on usual POP3S access on one of many servers: pop3-login: Error: Failed to initialize SSL server context: Can't load SSL certificate (ssl_cert setting): The certificate is empty: I'm running 2.3.14 compiled against openssl-1.1.1k on Debian Buster Looks like it's this code: https://github.com/dovecot/core/blob/a5209c83c3a82386c94d466eec5fea394973e8… called from here: https://github.com/dovecot/core/blob/a5209c83c3a82386c94d466eec5fea394973e8… To me it /looks/ like a resource problem. The farm handle a million pop3 sessions per hour while only 50k (5%) are using TLS. The farm is up and running since ~2 weeks. When started, the automatic deployment *did* check that pop3s was working well. Also today on all farmservers the certificate file is valid, contain expected content. the server is currently offline but not restarted to allow further investigation. the setup is quite normal just checked over all Farmservers: - doveconf | grep ssl | sha256sum - sha256sum $( doveconf | grep 'ssl_cert = <' | awk -F\< '{ print $2 }' ) the output is identical. Any idea is appreciated ... Andreas

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Maildir to Mdbox and folder structure after the conversion
by Marco Usai 18 Jun '21

18 Jun '21

Using the dsync command I've converted a Dovecot mail folder from Maildir to Mdbox format. (see https://dovecot.org/pipermail/dovecot/2021-June/122304.html) The folder resulting from the conversion (see https://pastebin.com/6U4CDTQi ), however, has a completely different directory structure from the one used by the destination server where it will be transferred (see https://pastebin.com/nMEvqmqp ) What do I have to do to make the folder obtained after the conversion have a directory structure identical to the one used by the destination server ? Thank You.

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Empty response with userFile from doveadm HTTP API
by lab＠403.sk 18 Jun '21

18 Jun '21

Hi, I must be doing something terribly wrong, but I am not able to get a non empty response from doveadm HTTP API when using userFile parameter. E. g. in getQuota or search command. Single user or wildcard working as expected. ./doveadm_cli.py --apikey $key --apiurl http://localhost:8180/doveadm/v1 (doveadm) quotaGet userFile=/tmp/f [] Results: 0 cat /tmp/f box1(a)domain.tld box2(a)domain.tld Result with plain cURL is exactly the same. curl -X POST http://localhost:8180/doveadm/v1 -H "Content-Type: application/json" -H "Authorization: X-Dovecot-API xxx" -d '[["quotaGet",{"userFile":"/tmp/f"},"tag1"]]' [["doveadmResponse",[],"tag1"]] Doveadm binary has no problem of reading that file. In a debug log I can see request finishes after "Handling LIST request" and does not jump to "Handling USER request" as in doveadm (binary) case. Am I missing something? dovecot: doveadm(::1): Executing command quota get dovecot: doveadm: Debug: auth-master: userdb list: Started listing users (user_mask=*) dovecot: doveadm: Debug: auth-master: conn unix:/var/run/dovecot/auth-userdb: Connecting dovecot: doveadm: Debug: auth-master: conn unix:/var/run/dovecot/auth-userdb (pid=13811,uid=0): Client connected (fd=8) dovecot: doveadm(::1): Debug: auth-master: userdb list: Finished listing users dovecot: doveadm(::1): Debug: auth-master: conn unix:/var/run/dovecot/auth-userdb (pid=13811,uid=0): Disconnected: Connection closed (fd=8) dovecot: auth: Debug: master in: LIST#0111#011user=* dovecot: doveadm(::1): doveadm: ::1 - - "POST /doveadm/v1 HTTP/1.1" 200 77 "http://localhost:8180/doveadm/v1" "python-requests/2.6.0 CPython/2.7.5" dovecot: auth-worker(13875): Debug: Loading modules from directory: /usr/lib64/dovecot/auth dovecot: auth-worker(13875): Debug: Module loaded: /usr/lib64/dovecot/auth/lib20_auth_var_expand_crypt.so dovecot: auth-worker(13875): Debug: Module loaded: /usr/lib64/dovecot/auth/libdriver_mysql.so dovecot: auth-worker(13875): Debug: Module loaded: /usr/lib64/dovecot/auth/libdriver_sqlite.so dovecot: auth-worker(13875): Debug: conn unix:auth-worker (pid=13839,uid=97): Server accepted connection (fd=15) dovecot: auth-worker(13875): Debug: conn unix:auth-worker (pid=13839,uid=97): Sending version handshake dovecot: auth-worker(13875): Debug: conn unix:auth-worker (pid=13839,uid=97): auth-worker<1>: Handling LIST request dovecot: auth-worker(13875): Debug: conn unix:auth-worker (pid=13839,uid=97): auth-worker<1>: sql(*): Performing userdb lookup dovecot: auth-worker(13875): Debug: conn unix:auth-worker (pid=13839,uid=97): auth-worker<1>: sql(*): SELECT email AS user FROM mailbox WHERE active=1 dovecot: auth-worker(13875): Debug: conn unix:auth-worker (pid=13839,uid=97): auth-worker<1>: sql(*): Finished userdb lookup dovecot: auth-worker(13875): Debug: conn unix:auth-worker (pid=13839,uid=97): auth-worker<1>: Finished doveconf -n # 2.3.14 (cee3cbc0d): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.14 (1b5c82b2) # OS: Linux 3.10.0-862.2.3.el7.x86_64 x86_64 CentOS Linux release 7.5.1804 (Core) # Hostname: xxx auth_debug = yes auth_mechanisms = plain login cram-md5 auth_verbose = yes default_client_limit = 6000 default_process_limit = 512 disable_plaintext_auth = no doveadm_api_key = # hidden, use -P to show it mail_debug = yes mail_home = /h/v/%d/%n mail_location = maildir:~/Maildir mail_plugins = quota 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 mbox_write_locks = fcntl namespace inbox { inbox = yes list = yes location = mailbox "Deleted Items" { special_use = \Trash } mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Items" { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Spam { special_use = \Junk } mailbox Trash { special_use = \Trash } prefix = type = private } passdb { args = /etc/dovecot/local-sql.conf driver = sql } plugin { quota = maildir quota_grace = 10M quota_rule2 = Kos:storage=+100M quota_rule3 = Trash:storage=+100M quota_rule4 = Deleted Messages:storage=+100M quota_status_nouser = DUNNO quota_status_overquota = 552 5.2.2 Mailbox is full quota_status_success = DUNNO sieve = file:~/sieve;active=~/.dovecot.sieve } service auth-worker { idle_kill = 30 secs } service auth { unix_listener /var/spool/postfix/private/auth { group = mail mode = 0660 user = postfix } unix_listener auth-userdb { mode = 0600 user = vmail } } service doveadm { client_limit = 1 inet_listener http { address = localhost port = 8180 } process_min_avail = 1 unix_listener doveadm-server { mode = 0600 user = vmail } user = vmail } service imap-login { process_limit = 4096 process_min_avail = 10 service_count = 1 } service imap { process_limit = 4096 } service lmtp { process_min_avail = 5 unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0600 user = postfix } user = vmail } service pop3-login { client_limit = 2048 } service quota-status { client_limit = 1 executable = quota-status -p postfix process_min_avail = 5 unix_listener /var/spool/postfix/private/dovecot-quota-status { group = postfix mode = 0600 user = postfix } user = vmail } ssl_ca = </etc/pki/tls/cert.pem ssl_cert = </etc/pki/o/default.pem ssl_cipher_list = HIGH:!aNULL:!SSLv2:!ADH:!EXP:!eNULL:!RC4:!MEDIUM:!LOW ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it ssl_prefer_server_ciphers = yes userdb { driver = prefetch } userdb { args = /etc/dovecot/local-sql.conf driver = sql } verbose_proctitle = yes protocol lmtp { mail_plugins = quota sieve } protocol imap { mail_max_userip_connections = 50 mail_plugins = quota imap_quota } Kind regards, Libor

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