Bug 1673415 (CVE-2019-3814) - CVE-2019-3814 dovecot: Improper certificate validation
Summary: CVE-2019-3814 dovecot: Improper certificate validation
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2019-3814
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: 1673416 1674369 1674370
Blocks: 1673418
TreeView+ depends on / blocked
 
Reported: 2019-02-07 13:23 UTC by Dhananjay Arunesh
Modified: 2021-02-16 22:23 UTC (History)
1 user (show)

Fixed In Version: dovecot 2.2.36.1, dovecot 2.3.4.1
Doc Type: If docs needed, set a value
Doc Text:
It was discovered that Dovecot incorrectly handled client certificates. A remote attacker in possession of a valid certificate with an empty username field could possibly use this issue to impersonate other users.
Clone Of:
Environment:
Last Closed: 2019-11-06 00:52:09 UTC


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2019:3467 0 None None None 2019-11-05 20:58:31 UTC
Red Hat Product Errata RHSA-2020:1062 0 None None None 2020-03-31 19:17:51 UTC

Description Dhananjay Arunesh 2019-02-07 13:23:30 UTC
It was discovered that Dovecot incorrectly handled client certificates. A
remote attacker in possession of a valid certificate with an empty username
field could possibly use this issue to impersonate other users.

References:
https://security-tracker.debian.org/tracker/source-package/dovecot
https://usn.ubuntu.com/usn/usn-3881-1
https://usn.ubuntu.com/usn/usn-3881-2

Comment 1 Dhananjay Arunesh 2019-02-07 13:23:50 UTC
Created dovecot tracking bugs for this issue:

Affects: fedora-all [bug 1673416]

Comment 2 Dhananjay Arunesh 2019-02-07 14:22:53 UTC
External References:

https://www.dovecot.org/list/dovecot/2019-February/114575.html

Comment 3 Huzaifa S. Sidhpurwala 2019-02-11 07:16:27 UTC
This basically affects installation which enable client-side certs. When authenticating with a cert which has empty "user" field, vulnerable versions take the loginame from the user. If no additional password is configured this will allow the user to impersonate anyone else in the system.

Comment 4 Huzaifa S. Sidhpurwala 2019-02-11 07:16:30 UTC
Mitigation:

Attack can be migitated by having the certificates with proper Extended Key Usage, such as 'TLS Web Server' and 'TLS Web Server Client'. Also client-side certification authentication can be turned off using:
auth_ssl_require_client_cert = no
auth_ssl_username_from_cert = no

Comment 6 errata-xmlrpc 2019-11-05 20:58:30 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2019:3467 https://access.redhat.com/errata/RHSA-2019:3467

Comment 7 Product Security DevOps Team 2019-11-06 00:52:09 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2019-3814

Comment 8 errata-xmlrpc 2020-03-31 19:17:50 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:1062 https://access.redhat.com/errata/RHSA-2020:1062


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