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May 2020

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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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