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CVE-2019-10691: JSON encoder in Dovecot 2.3 incorrecty assert-crashes when encountering invalid UTF-8 characters.
by Aki Tuomi 18 Apr '19

18 Apr '19

Dear subscribers, we're sharing our latest advisory with you and would like to thank everyone who contributed in finding and solving those vulnerabilities. Feel free to join our bug bounty programs (open-xchange, dovecot, powerdns) at HackerOne. You can find binary packages at https://repo.dovecot.org/ Yours sincerely, Aki Tuomi Open-Xchange Oy Open-Xchange Security Advisory 2019-04-18 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-3173 (Bug ID) Vulnerability type: CWE-176 Vulnerable version: 2.3.0 - 2.3.5.1 Vulnerable component: json encoder Report confidence: Confirmed Researcher credits: cPanel L.L.C. Solution status: Fixed by Vendor Fixed version: 2.3.5.2 Vendor notification: 2019-04-02 Solution date: 2019-04-11 Public disclosure: 2019-04-18 CVE reference: CVE-2019-10691 CVSS: 7.5 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Vulnerability Details: JSON encoder in Dovecot 2.3 incorrecty assert-crashes when encountering invalid UTF-8 characters. This can be used to crash dovecot in two ways. Attacker can repeatedly crash Dovecot authentication process by logging in using invalid UTF-8 sequence in username. This requires that auth policy is enabled. Crash can also occur if OX push notification driver is enabled and an email is delivered with invalid UTF-8 sequence in From or Subject header. In 2.2, malformed UTF-8 sequences are forwarded "as-is", and thus do not cause problems in Dovecot itself. Target systems should be checked for possible problems in dealing with such sequences. See https://wiki.dovecot.org/Authentication/Policy for details on auth policy support. Risk: Determined attacker can prevent authentication process from staying up by keeping on attempting to log in with username containing invalid UTF-8 sequence. Steps to reproduce: Configure dovecot with auth_policy_server_url and auth_policy_hash_nonce set. Attempt to log in with username containing an invalid UTF-8 sequence Observe assert-crash in dovecot logs. Solution: Operators should update to the latest Patch Release or disable auth policy support.

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v2.3.5.2 released
by Aki Tuomi 18 Apr '19

18 Apr '19

https://dovecot.org/releases/2.3/dovecot-2.3.5.2.tar.gz https://dovecot.org/releases/2.3/dovecot-2.3.5.2.tar.gz.sig Binary packages in https://repo.dovecot.org/ * CVE-2019-7524: Missing input buffer size validation leads into arbitrary buffer overflow when reading fts or pop3 uidl header from Dovecot index. Exploiting this requires direct write access to the index files. --- Aki Tuomi Open-Xchange oy

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v2.2.36.3 released
by Aki Tuomi 28 Mar '19

28 Mar '19

https://dovecot.org/releases/2.3/dovecot-2.2.36.3.tar.gz https://dovecot.org/releases/2.3/dovecot-2.2.36.3.tar.gz.sig * CVE-2019-7524: Missing input buffer size validation leads into arbitrary buffer overflow when reading fts or pop3 uidl header from Dovecot index. Exploiting this requires direct write access to the index files. --- Aki Tuomi Open-Xchange oy

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CVE-2019-7524: Buffer overflow when reading extension header from dovecot index files
by Aki Tuomi 28 Mar '19

28 Mar '19

Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-2964 (Bug ID) Vulnerability type: CWE-120 Vulnerable version: 2.0.14 - 2.3.5 Vulnerable component: fts, pop3-uidl-plugin Report confidence: Confirmed Researcher credits: Found in internal testing Solution status: Fixed by Vendor Fixed version: 2.3.5.1, 2.2.36.3 Vendor notification: 2019-02-05 Solution date: 2019-03-21 Public disclosure: 2019-03-28 CVE reference: CVE-2019-7524 CVSS: 3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C (8.8) Vulnerability Details: When reading FTS or POP3-UIDL header from dovecot index, the input buffer size is not bound, and data is copied to target structure causing stack overflow. Risk: This can be used for local root privilege escalation or executing arbitrary code in dovecot process context. This requires ability to directly modify dovecot indexes. Steps to reproduce: Produce dovecot.index.log entry that creates an FTS header which has more than 12 bytes of data. Trigger dovecot indexer-worker or run doveadm index. Dovecot will crash. Mitigations: Since 2.3.0 dovecot has been compiled with stack smash protection, ASLR, read-only GOT tables and other techniques that make exploiting this bug much harder. Solution: Operators should update to the latest Patch Release. The only workaround is to disable FTS and pop3-uidl plugin. -- Aki Tuomi Open-Xchange Oy

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v2.3.5.1 released
by Aki Tuomi 28 Mar '19

28 Mar '19

https://dovecot.org/releases/2.3/dovecot-2.3.5.1.tar.gz https://dovecot.org/releases/2.3/dovecot-2.3.5.1.tar.gz.sig Binary packages in https://repo.dovecot.org/ * CVE-2019-7524: Missing input buffer size validation leads into arbitrary buffer overflow when reading fts or pop3 uidl header from Dovecot index. Exploiting this requires direct write access to the index files. --- Aki Tuomi Open-Xchange oy

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Pigeonhole v0.5.5 released
by Aki Tuomi 05 Mar '19

05 Mar '19

Hi! We are happy to release pigeonhole v0.5.5 for dovecot v2.3.5. Please find sources at https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.5.ta… https://pigeonhole.dovecot.org/releases/2.3/dovecot-2.3-pigeonhole-0.5.5.ta… (Please note that the signing key has been changed for 0.5.5, see https://pigeonhole.dovecot.org/download.html for details.) You can find precompiled binaries at https://repo.dovecot.org/ NEWS: + IMAPSieve: Add new plugin/imapsieve_expunge_discarded setting which causes messages discarded by an IMAPSieve script to be expunged immediately, rather than only being marked as "\Deleted" (which is still the default behavior). - IMAPSieve: Fix panic crash occurring when a COPY command copies messages from a virtual mailbox where the source messages originate from more than a single real mailbox. - imap4flags extension: Fix deleting all keywords. When the action resulted in all keywords being removed, no changes were actually applied. - variables extension: Fix truncation of UTF-8 variable content. The maximum size of Sieve variables was enforced by truncating the variable string content bluntly at the limit, but this does not consider UTF-8 code point boundaries. This resulted in broken UTF-8 strings. This problem also surfaced for variable modifiers, such as the ":encodeurl" modifier provided by the Sieve "enotify" extension. In that case, the resulting URI escaping could also be truncated inappropriately. - IMAPSieve, IMAP FILTER=SIEVE: Fix replacing a modified message. Sieve scripts running in IMAPSIEVE or IMAP FILTER=SIEVE context that modify the message, stored the message a second time, rather than replacing the originally stored unmodified message. - Fix segmentation fault occurring when both the sieve_extprograms plugin (for the Sieve interpreter) and the imap_filter_sieve plugin (for IMAP) are loaded at the same time. A symbol was defined by both plugins, causing a clash when both were loaded. --- Aki Tuomi Open-Xchange Oy

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Dovecot v2.3.5 released
by Aki Tuomi 05 Mar '19

05 Mar '19

Hi! We are happy to release dovecot v2.3.5. Please find sources at https://dovecot.org/releases/2.3/dovecot-2.3.5.tar.gz https://dovecot.org/releases/2.3/dovecot-2.3.5.tar.gz.sig You can find precompiled binaries at https://repo.dovecot.org/ NEWS: + Lua push notification driver: mail keywords and flags are provided in MessageNew and MessageAppend events. + submission: Implement support for plugins. + auth: When auth_policy_log_only=yes, only log what the policy server response would do without actually doing it. + auth: Always log policy server decisions with auth_verbose=yes - v2.3.[34]: doveadm log errors: Output was missing user/session - lda: Debug log lines could have shown slightly corrupted - login proxy: Login processes may have crashed in various ways when login_proxy_max_disconnect_delay was set. - imap: Fix crash with Maildir+zlib if client disconnects during APPEND - lmtp proxy: Fix potential assert-crash - lmtp/submission: Fix crash when SMTP client transaction times out - submission: Split large XCLIENT commands to 512 bytes per command, so Postfix accepts them. - submission: Fix crash when client sends invalid BURL command - submission: relay backend: VRFY command: Avoid forwarding 500 and 502 replies back to client. - lib-http: Fix potential assert-crash when DNS lookup fails - lib-fts: Fix search query generation when one language ignores a token (e.g. via stopwords). --- Aki Tuomi Open-Xchange Oy

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Re: [Dovecot-news] Release notify (2.2.36.1 and 2.3.4.1)
by Aki Tuomi 05 Feb '19

05 Feb '19

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Re: [Dovecot-news] Release notify (2.2.36.1 and 2.3.4.1)
by Aki Tuomi 05 Feb '19

05 Feb '19

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Re: [Dovecot-news] Dovecot v2.2.36.1 released (Pigeonhole 0.4.24.1)
by Stephan Bosch 05 Feb '19

05 Feb '19

Hi, Here is the associated release for Pigeonhole: https://pigeonhole.dovecot.org/releases/2.2/dovecot-2.2-pigeonhole-0.4.24.1… https://pigeonhole.dovecot.org/releases/2.2/dovecot-2.2-pigeonhole-0.4.24.1… Binary packages included in https://repo.dovecot.org/ + imapsieve: Added imapsieve_expunge_discarded setting which causes discarded messages to be expunged immediately. - Sieve scripts running in IMAPSIEVE or IMAP FILTER=SIEVE context that modify the message, store the message a second time, rather than replacing the originally stored unmodified message. - imapsieve: Fix crash when COPYing mails from a virtual mailbox when the source messages originate from more than a single real mailbox - imap_filter_sieve plugin: Implement the missing UID FILTER command. - imap_filter_sieve plugin: Fix FILTER to work with pipelining Regards, Stephan. Op 5-2-2019 om 14:01 schreef Aki Tuomi: > https://dovecot.org/releases/2.2/dovecot-2.2.36.1.tar.gz > https://dovecot.org/releases/2.2/dovecot-2.2.36.1.tar.gz.sig > > * CVE-2019-3814: If imap/pop3/managesieve/submission client has > trusted certificate with missing username field > (ssl_cert_username_field), under some configurations Dovecot > mistakenly trusts the username provided via authentication instead > of failing. > * ssl_cert_username_field setting was ignored with external SMTP AUTH, > because none of the MTAs (Postfix, Exim) currently send the > cert_username field. This may have allowed users with trusted > certificate to specify any username in the authentication. This bug > didn't affect Dovecot's Submission service. > > - pop3_no_flag_updates=no: Don't expunge RETRed messages without QUIT > - director: Kicking a user assert-crashes if login process is very slow > - lda/lmtp: Fix assert-crash with some Sieve scripts when > mail_attachment_detection_options=add-flags-on-save > - fs-compress: Using maybe-gz assert-crashed when reading 0 sized file > - Snippet generation crashed with invalid Content-Type:multipart > > > --- > > Aki Tuomi > Open-Xchange Oy > >

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