Bug 2105070 (CVE-2022-30550) - dovecot: Privilege escalation possible in dovecot when similar master and non-master passdbs are used
Summary: dovecot: Privilege escalation possible in dovecot when similar master and non...
Keywords:
Status: NEW
Alias: CVE-2022-30550
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2106227 2106229 2106231 2106232 2106228
Blocks: 2105072
TreeView+ depends on / blocked
 
Reported: 2022-07-07 20:13 UTC by amctagga
Modified: 2022-08-03 12:19 UTC (History)
7 users (show)

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Doc Text:
A vulnerability was found in the Dovecot IMAP Server. 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 incorrect settings can lead to an unintended security configuration and can permit privilege escalation with certain configurations involving a master user authentication. If the same passwd file or PAM is used for both normal and master users, an attacker could easily become a master user, potentially escalating privileges on the system.
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Description amctagga 2022-07-07 20:13:55 UTC
Affected product: Dovecot IMAP Server 
Internal reference: DOV-5320
Vulnerability type: Improper Access Control (CWE-284) 
Vulnerable version: 2.2
Vulnerable component: submission 
Report confidence: Confirmed 
Solution status: Fixed in main
Researcher credits: Julian Brook (julezman)
Vendor notification: 2022-05-06 
CVE reference: CVE-2022-30550
CVSS: 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.patch

Comment 1 Petr Pisar 2022-07-08 07:28:59 UTC
dovecot is not maintained by jplesnik, removing from CC.

Comment 2 Michal Josef Spacek 2022-07-08 10:05:30 UTC
And not related to Perl.

Comment 4 TEJ RATHI 2022-07-12 06:22:57 UTC
Created dovecot tracking bugs for this issue:

Affects: fedora-all [bug 2106228]


Created dovecot-fts-xapian tracking bugs for this issue:

Affects: epel-8 [bug 2106227]
Affects: fedora-all [bug 2106229]


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