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Dovecot IMAP Server 2.2 Improper Access Control
Dovecot IMAP server version 2.2 suffers from a privilege escalation vulnerability. When two passdb configuration entries exist in the Dovecot configuration, which have the same driver and args settings, the incorrect username_filter and mechanism settings can be applied to passdb definitions. These incorrectly applied settings can lead to an unintended security configuration and can permit privilege escalation with certain configurations involving master user authentication.
Affected product: Dovecot IMAP Server Internal reference: DOV-5320Vulnerability type: Improper Access Control (CWE-284) Vulnerable version: 2.2Vulnerable component: submission Report confidence: Confirmed Solution status: Fixed in mainResearcher credits: Julian Brook (julezman)Vendor notification: 2022-05-06 CVE reference: CVE-2022-30550CVSS: 6.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N) Vulnerability Details: When two passdb configuration entries exist in Dovecot configuration, which have the same driver and args settings, the incorrect username_filter and mechanism settings can be applied to passdb definitions. These incorrectly applied settings can lead to an unintended security configuration and can permit privilege escalation with certain configurations involving master user authentication.Dovecot documentation does not advise against the use of passdb definitions which have the same driver and args settings. One such configuration would be where an administrator wishes to use the same pam configuration or passwd file for both normal and master users but use the username_filter setting to restrict which of the users is able to be a master user.Risk: If same passwd file or PAM is used for both normal and master users, it is possible for attacker to become master user.Workaround:Always authenticate master users from different source than regular users, e.g. using a separate passwd file. Alternatively, you can use global ACLs to ensure that only legimate master users have priviledged access.Fix:This has been fixed in main branch. See https://github.com/dovecot/core/compare/7bad6a24%5E..a1022072.patchRelated news
Gentoo Linux Security Advisory 202310-19 - A vulnerability has been discovered in Dovecot that can lead to a privilege escalation when master and non-master passdbs are used. Versions greater than or equal to 2.3.19.1-r1 are affected.
Red Hat Security Advisory 2022-8208-01 - Dovecot is an IMAP server for Linux and other UNIX-like systems, written primarily with security in mind. It also contains a small POP3 server, and supports e-mail in either the maildir or mbox format. The SQL drivers and authentication plug-ins are provided as subpackages. Issues addressed include a privilege escalation vulnerability.
An update for dovecot is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original. Related CVEs: * CVE-2022-30550: dovecot: Privilege escalation when similar master and non-master passdbs are used
An update for dovecot is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original. Related CVEs: * CVE-2022-30550: dovecot: Privilege escalation when similar master and non-master passdbs are used
An issue was discovered in the auth component in Dovecot 2.2 and 2.3 before 2.3.20. When two passdb configuration entries exist with the same driver and args settings, incorrect username_filter and mechanism settings can be applied to passdb definitions. These incorrectly applied settings can lead to an unintended security configuration and can permit privilege escalation in certain configurations. The documentation does not advise against the use of passdb definitions that have the same driver and args settings. One such configuration would be where an administrator wishes to use the same PAM configuration or passwd file for both normal and master users but use the username_filter setting to restrict which of the users is able to be a master user.
Ubuntu Security Notice 5509-1 - Julian Brook discovered that Dovecot incorrectly handled multiple passdb configuration entries. In certain configurations, a remote attacker could possibly use this issue to escalate privileges.