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CVE-2020-12100: Receiving mail with deeply nested MIME parts leads to resource exhaustion.
by Aki Tuomi 12 Aug '20

12 Aug '20

Open-Xchange Security Advisory 2020-08-12 Affected product: Dovecot IMAP server Internal reference: DOP-1849 (Bug ID) Vulnerability type: Uncontrolled recursion (CWE-674) Vulnerable version: 2.0 Vulnerable component: submission, lmtp, lda Fixed version: 2.3.11.3 Report confidence: Confirmed Solution status: Fix available Vendor notification: 2020-04-23 CVE reference: CVE-2020-12100 CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Vulnerability Details: Receiving mail with deeply nested MIME parts leads to resource exhaustion as Dovecot attempts to parse it. Risk: Malicious actor can cause denial of service to mail delivery by repeatedly sending mails with bad content. Workaround: Limit MIME structures in MTA. Solution: Upgrade to fixed version. Best regards, Aki Tuomi Open-Xchange oy

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Dovecot v2.3.11.3 released
by Aki Tuomi 12 Aug '20

12 Aug '20

We are pleased to release v2.3.11.3. Please find it from locations below: https://dovecot.org/releases/2.3/dovecot-2.3.11.3.tar.gz https://dovecot.org/releases/2.3/dovecot-2.3.11.3.tar.gz.sig Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot Aki Tuomi Open-Xchange oy --- * CVE-2020-12100: Parsing mails with a large number of MIME parts could have resulted in excessive CPU usage or a crash due to running out of stack memory. * CVE-2020-12673: Dovecot's NTLM implementation does not correctly check message buffer size, which leads to reading past allocation which can lead to crash. * CVE-2020-10967: lmtp/submission: Issuing the RCPT command with an address that has the empty quoted string as local-part causes the lmtp service to crash. * CVE-2020-12674: Dovecot's RPA mechanism implementation accepts zero-length message, which leads to assert-crash later on. * Events: Fix inconsistency in events. See event documentation in https://doc.dovecot.org. * imap_command_finished event's cmd_name field now contains "unknown" for unknown commands. A new "cmd_input_name" field contains the command name exactly as it was sent. * lib-index: Renamed mail_cache_compress_* settings to mail_cache_purge_*. Note that these settings are mainly intended for testing and usually shouldn't be changed. * events: Renamed "index" event category to "mail-index". * events: service:<name> category is now using the name from configuration file. * dns-client: service dns_client was renamed to dns-client. * log: Prefixes generally use the service name from configuration file. For example dict-async service will now use "dict-async(pid): " log prefix instead of "dict(pid): " * *-login: Changed logging done by proxying to use a consistent prefix containing the IP address and port. * *-login: Changed disconnection log messages to be slightly clearer. + dict: Add events for dictionaries. + lib-index: Finish logging with events. + oauth2: Support local validation of JWT tokens. + stats: Add support for dynamic histograms and grouping. See https://doc.dovecot.org/configuration_manual/stats/. + imap: Implement RFC 8514: IMAP SAVEDATE + lib-index: If a long-running transaction (e.g. SORT/FETCH on a huge folder) adds a lot of data to dovecot.index.cache file, commit those changes periodically to make them visible to other concurrent sessions as well. + stats: Add OpenMetrics exporter for statistics. See https://doc.dovecot.org/configuration_manual/stats/openmetrics/. + stats: Support disabling stats-writer socket by setting stats_writer_socket_path="". - auth-worker: Process keeps slowly increasing its memory usage and eventually dies with "out of memory" due to reaching vsz_limit. - auth: Prevent potential timing attacks in authentication secret comparisons: OAUTH2 JWT-token HMAC, imap-urlauth token, crypt() result. - auth: Several auth-mechanisms allowed input to be truncated by NUL which can potentially lead to unintentional issues or even successful logins which should have failed. - auth: When auth policy returned a delay, auth_request_finished event had policy_result=ok field instead of policy_result=delayed. - auth: auth process crash when auth_policy_server_url is set to an invalid URL. - auth: Lua passdb/userdb leaks stack elements per call, eventually causing the stack to become too deep and crashing the auth or auth-worker process. - dict-ldap: Crash occurs if var_expand template expansion fails. - dict: If dict client disconnected while iteration was still running, dict process could have started using 100% CPU, although it was still handling clients. - doveadm: Running doveadm commands via proxying may hang, especially when doveadm is printing a lot of output. - imap: "MOVE * destfolder" goes to a loop copying the last mail to the destination until the imap process dies due to running out of memory. - imap: Running "UID MOVE 1:* Trash" on an empty folder goes to infinite loop. - imap: SEARCH doesn't support $. - lib-compress: Buffer over-read in zlib stream read. - lib-dns: If DNS lookup times out, lib-dns can cause crash in calling process. - lib-index: Fixed several bugs in dovecot.index.cache handling that could have caused cached data to be lost. - lib-index: Writing to >=1 GB dovecot.index.cache files may cause assert-crashes: Panic: file mail-index-util.c: line 37 (mail_index_uint32_to_offset): assertion failed: (offset < 0x40000000) - lib-mail: v2.3.11 regression: MIME parts not returned correctly by Dovecot MIME parser. - lib-ssl-iostream: Fix buggy OpenSSL error handling without assert-crashing. If there is no error available, log it as an error instead of crashing: Panic: file iostream-openssl.c: line 599 (openssl_iostream_handle_error): assertion failed: (errno != 0) - lib-ssl-iostream: ssl_key_password setting did not work. - pop3-login: Login didn't handle commands in multiple IP packets properly. This mainly affected large XCLIENT commands or a large SASL initial response parameter in the AUTH command. - pop3: pop3_deleted_flag setting was broken, causing: Panic: file seq-range-array.c: line 472 (seq_range_array_invert): assertion failed: (range[count-1].seq2 <= max_seq) - pop3-login: Login would fail with "Input buffer full" if the initial response for SASL was too long. - submission: A segfault crash may occur when the client or server disconnects while a non-transaction command like NOOP or VRFY is still being processed. - virtual: Copying/moving mails with IMAP into a virtual folder assert-crashes: Panic: file cmd-copy.c: line 152 (fetch_and_copy): assertion failed: (copy_ctx->copy_count == seq_range_count(&copy_ctx->saved_uids))

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Pigeonhole 0.5.11 released
by Aki Tuomi 12 Aug '20

12 Aug '20

We are pleased to release pigeonhole 0.5.11. You can download it from locations below: https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3.11-pigeonhole-0.5.1… https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3.11-pigeonhole-0.5.1… Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot Aki Tuomi Open-Xchange oy --- * managesieve: managesieve_max_line_length setting is now a "size" type instead of just number of bytes. This allows using e.g. "64k" as the value. - lib-sieve: When folding white space is used in the Message-ID header, it is not stripped away correctly before the message ID value is used, causing e.g. garbled log lines at delivery.

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Multiple vulnerabilities in Dovecot
by Aki Tuomi 18 May '20

18 May '20

Dear subscribers, we are sending notifications for three vulnerabilities, - CVE-2020-10957 - CVE-2020-10958 - CVE-2020-10967 Please find them below --- Aki Tuomi Open-Xchange Oy ------------------ Open-Xchange Security Advisory 2020-05-18 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-3784 Vulnerability type: NULL pointer dereference (CWE-476) Vulnerable version: 2.3.0 - 2.3.10 Vulnerable component: submission, lmtp Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.10.1 Researcher credits: Philippe Antoine (Catena Cyber) Vendor notification: 2020-03-24 Solution date: 2020-04-02 Public disclosure: 2020-05-18 CVE reference: CVE-2020-10957 CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Vulnerability Details: Sending malformed NOOP command causes crash in submission, submission-login or lmtp service. Risk: Remote attacker can keep submission-login service down, causing denial of service attack. For lmtp the risk is neglible, as lmtp is usually behind a trusted MTA. Steps to reproduce: Send ``NOOP EE"FY`` to submission port, or similarly malformed command. Solution: Upgrade to fixed version. ------------------ Open-Xchange Security Advisory 2020-05-18 Product: Dovecot IMAP server Vendor: OX Software GmbH Internal reference: DOV-3875 Vulnerability type: Improper handling of input data (CWE-20) Vulnerable version: 2.3.0 - 2.3.10 Vulnerable component: submission, lmtp Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.10.1 Researcher credits: Philippe Antoine (Catena Cyber) Vendor notification: 2020-03-23 Solution date: 2020-04-02 Public disclosure: 2020-05-18 CVE reference: CVE-2020-10958 CVSS: 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L) Vulnerability Details: Sending command followed by sufficient number of newlines triggers a use-after-free bug that might crash submission-login, submission or lmtp service. Risk: Remote attacker can keep submission-login service down, causing denial of service attack. For lmtp the risk is neglible, as lmtp is usually behind a trusted MTA. Steps to reproduce: This can be currently reproduced with ASAN or Valgrind. Reliable way to crash has not yet been discovered. Solution: Upgrade to fixed version. ------------------ Open-Xchange Security Advisory 2020-05-18 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-1745 Vulnerability type: Improper input validation (CWE-20) Vulnerable version: 2.3.0 - 2.3.10 Vulnerable component: submission, lmtp Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.10.1 Researcher credits: mailbox.org Vendor notification: 2020-03-20 Solution date: 2020-04-02 Public disclosure: 2020-05-18 CVE reference: CVE-2020-10967 CVSS: 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L) Vulnerability Details: Sending mail with empty quoted localpart causes submission or lmtp component to crash. Risk: Malicious actor can cause denial of service to mail delivery by repeatedly sending mails with bad sender or recipient address. Steps to reproduce: Send mail with envelope sender or recipient as ``<""@example.org>``. Workaround: For submission there is no workaround, but triggering the bug requires valid credentials. For lmtp, one can implement sufficient filtering on MTA level to prevent mails with such addresses from ending up in LMTP delivery. Solution: Upgrade to fixed version. ------------------

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v2.3.10.1 released
by Aki Tuomi 18 May '20

18 May '20

We are pleased to release v2.3.10.1 Please find it from locations below: https://dovecot.org/releases/2.3/dovecot-2.3.10.1.tar.gz https://dovecot.org/releases/2.3/dovecot-2.3.10.1.tar.gz.sig Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot Aki Tuomi Open-Xchange oy --- - CVE-2020-10957: lmtp/submission: A client can crash the server by sending a NOOP command with an invalid string parameter. This occurs particularly for a parameter that doesn't start with a double quote. This applies to all SMTP services, including submission-login, which makes it possible to crash the submission service without authentication. - CVE-2020-10958: lmtp/submission: Sending many invalid or unknown commands can cause the server to access freed memory, which can lead to a server crash. This happens when the server closes the connection with a "421 Too many invalid commands" error. The bad command limit depends on the service (lmtp or submission) and varies between 10 to 20 bad commands. - CVE-2020-10967: lmtp/submission: Issuing the RCPT command with an address that has the empty quoted string as local-part causes the lmtp service to crash.

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Headsup on feature removal
by Aki Tuomi 17 Mar '20

17 Mar '20

Hi! Dovecot is now a nearly 20 year old product, and during that time it has accumulated many different features and plugins in its core repository. We are starting to gradually remove some of these parts, which are unused, untested or deprecated. We will provide advance notification before removing anything. To start, the following features are likely to be removed in next few releases of Dovecot. - Authentication drivers: vpopmail, checkpassword, bsdauth, shadow, sia - Password schemes: HMAC-MD5, RPA, SKEY, PLAIN-MD4, LANMAN, NTLM, SMD5 - Authentication mechanisms: ntlm, rpa, skey - Dict drivers: memcached, memcached-ascii (use redis instead) - postfix postmap support - autocreate & autosubscribe plugins (use built-in auto=create/subscribe setting instead) - expire plugin (use built-in autoexpunge setting) - fts-squat plugin - mailbox alias plugin - mail-filter plugin - snarf plugin - xz compression algorithm For the authentication drivers that are being removed, we suggest using Lua as a replacement. See https://doc.dovecot.org/configuration_manual/authentication/lua_based_authe… For information about converting between password schemes, see https://wiki2.dovecot.org/HowTo/ConvertPasswordSchemes If you are using any of these features, please start preparing for their removal in the near future. Features will begin to be dropped as of v2.3.11. Additionally, the mbox format will no longer receive new development. It will still be maintained, however its use beyond migrations and other limited use cases will be discouraged. Please contact us via the mailing list if you have any questions. Regards, Dovecot Team

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Pigeonhole v0.5.10 release notes
by Aki Tuomi 11 Mar '20

11 Mar '20

Hi! We made a mistake of releasing pigeonhole with wrong release notes, so please find the correct release notes here. Also if you are using `--without-dovecot-install-dirs`, you must use `--with-moduledir`. Otherwise the Makefile gets broken. v0.5.10 2020-03-06 Aki Tuomi <aki.tuomi(a)open-xchange.com> * imap_sieve_filter: Change result action logging to include IMAP UID - vacation: Addresses were compared case-sensitively. Aki Tuomi

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Dovecot v2.3.10 Released
by Aki Tuomi 06 Mar '20

06 Mar '20

We are pleased to release v2.3.10 of Dovecot. Please find it from locations below: https://dovecot.org/releases/2.3/dovecot-2.3.10.tar.gz https://dovecot.org/releases/2.3/dovecot-2.3.10.tar.gz.sig Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot Aki Tuomi Open-Xchange oy --- * Disable retpoline migitations by default. These can cause severe performance regressions, so they should be only enabled when applicable. * IMAP MOVE now commits transactions in batches of 1000 mails. This helps especially with lazy_expunge when moving a lot of mails. It mainly avoids situations where multiple IMAP sessions are running the same MOVE command and duplicating the mails in the lazy_expunge folder. With this change there can still be some duplication, but the MOVE always progresses forward. Also if the MOVE fails at some point, the changes up to the last 1000 mails are still committed instead of rolled back. Note that the COPY command behavior hasn't changed, because it is required by IMAP standard to be an atomic operation. * IMAP EXPUNGE and CLOSE now expunges mails in batches of 1000 mails. This helps especially with lazy_expunge when expunging a lot of mails (e.g. millions) to make sure that the progress always moves forward even if the process is killed. * Autoexpunging now expunges mails in batches of 1000 mails. This helps especially with lazy_expunge when expunging a lot of mails (e.g. millions) to make sure that the progress always moves forward even if the process is killed. + Add tool for generating sysreport called dovecot-sysreport. This generates a bundle of information usually needed for support requests. + Add support for the new IMAP \Important SPECIAL-USE flag (RFC 8457). + Add metric { group_by } setting. This allows automatically creating new metrics based on the fields you want to group statistics by. NOTE: This feature is considered experimental and syntax is subject to change in future release. + auth: Support SCRAM-SHA-256 authentication mechanism. + imap: Support the new IMAP STATUS=SIZE extension. + Use TCP_QUICKACK to reduce latency for some TCP connections. + quota-status: Made the service more robust against erroneous use with Postfix ACL policies other than smtpd_recipient_restrictions. + Add "revision" field support to imap_id_send setting. Using "revision *" will send in IMAP ID command response the short commit hash of the Dovecot git source tree HEAD (same as in dovecot --version). + IMAP ENVELOPE includes now all addresses when there are multiple headers (From, To, Cc, etc.) The standard way of having multiple addresses is to just list them all in a single header. It's non-standard to have multiple headers. However, since MTAs allow these mails to pass through and different software may handle them in different ways, it's better from security point of view to show all the addresses. + Event filters now support using "field_name=" to match a field that doesn't exist or has an empty value. For example use "error=" to match only events that didn't fail. - acl: INBOX ACLs shouldn't apply for IMAP GETMETADATA/SETMETADATA commands. - cassandra: CASS_ERROR_SERVER_WRITE_FAILURE error should also be treated as "uncertain write failure". - dict-redis: Using quota_clone configured with dict-redis could have crashed when Redis responded slowly. - imap-hibernate: Communication trouble with imap-master leads to segfault. - imap-hibernate: Unhibernation retrying wasn't working. - imap: Fixed auth lookup privilege problem when imap process was reused and user was being un-hibernated. - Fix potential crash when copying/moving mails within the same folder. This happened only when there were a lot of fields in dovecot.index.cache. - lib-index: Recreating dovecot.index.cache file could have crashed when merging bitmask fields. - lib-index: Using public/shared folders with INDEXPVT configured to use private \Seen flags, trying to search seen/unseen in an empty folder crashes with segfault. - lib-mail: Large base64-encoded mails weren't decoded properly. This could have affected searching/indexing mails and message snippet generation. - lib-mail: Message with only quoted text could have caused message snippet to ignore its 200 character limit and return the entire message. This was added also to dovecot.index.cache file, which increased disk space and memory usage unnecessarily. v2.3.9.2 regression (previous versions cached the quoted snippet as empty). In a large mail quoted text could have become wrongly added to the snippet, possibly mixed together with non-quoted text. - lib-smtp: client could have assert-crashed if STARTTLS handshake finished earlier than usually. - lib-ssl-iostream: remove -static flag for lib-ssl-iostream linking to prevent a compile issue. - lib-storage: Mailbox synchronization may have assert-crashed in some rare situations. - lib-storage: mdbox didn't preserve date.saved with dsync. - lib: Don't require EAI_{ADDRFAMILY,NODATA}, breaks FreeBSD - master: Some services could respawn unthrottled if they crash during startup. - push-notification: Do not send push_notification_finished event if nothing was done. This happens when mail transaction is started and ended with no changes. - quota-status: Addresses with special characters in the local part caused problems in the interaction between Postfix and Dovecot. Postfix sent its own internal representation in the recipient field, while Dovecot expected a valid RFC5321 mailbox address. - submission-login: SESSION was not correctly encoded field for the XCLIENT command. Particularly, a '+' character introduced by the session ID's Base64 encoding causes problems. - submission: Fix submission_max_mail_size to work correctly on 32-bit systems. - submission: Trusted connections crashed in second connection's EHLO if submission-login { service_count } is something else than 1 (which is the default). - submission: XCLIENT command was never used in the protocol exchange with the relay MTA when submission_backend_capabilities is configured, even when the relay MTA was properly configured to accept the XCLIENT command.

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Pigeonhole v0.5.10 Released
by Aki Tuomi 06 Mar '20

06 Mar '20

We are doing a pigeonhole 0.5.10 release to maintain version number parity with dovecot. You can download it from locations below: https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.10.t… https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.10.t… Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot There are no other changes than version number. --- Aki Tuomi Open-Xchange oy

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CVE-2020-7046: Truncated UTF-8 can be used to DoS submission-login and lmtp processes
by Aki Tuomi 12 Feb '20

12 Feb '20

Open-Xchange Security Advisory 2020-02-12 Affected product: Dovecot Core Internal reference: DOV-3744 (JIRA ID) Vulnerability type: Improper Input Validation (CWE-30) Vulnerable version: 2.3.9 Vulnerable component: submission-login, lmtp Fixed version: 2.3.9.3 Report confidence: Confirmed Solution status: Fixed Researcher credits: Open-Xchange oy Vendor notification: 2020-01-14 CVE reference: CVE-2020-7046 CVSS: 7.5 (CVSS3.1:AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Vulnerability Details: lib-smtp doesn't handle truncated command parameters properly, resulting in infinite loop taking 100% CPU for the process. This happens for LMTP (where it doesn't matter so much) and also for submission-login where unauthenticated users can trigger it. Risk: Attacker can cause submission-login and lmtp processes to be exhausted, leading into denial of service and CPU resource exhaustion. Solution: Upgrade to 2.3.9.3.

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