Bug 55532 - samba: Multiple issues (4.4)
Summary: samba: Multiple issues (4.4)
Status: RESOLVED WONTFIX
Alias: None
Product: UCS
Classification: Unclassified
Component: Security updates
Version: UCS 4.4
Hardware: Other Linux
: P5 normal
Target Milestone: ---
Assignee: Arvid Requate
QA Contact: UCS maintainers
URL: https://help.univention.com/t/samba-d...
Keywords:
Depends on: 55511
Blocks:
  Show dependency treegraph
 
Reported: 2023-01-06 09:50 CET by Arvid Requate
Modified: 2023-01-06 21:17 CET (History)
3 users (show)

See Also:
What kind of report is it?: Security Issue
What type of bug is this?: ---
Who will be affected by this bug?: ---
How will those affected feel about the bug?: ---
User Pain:
Enterprise Customer affected?: Yes
School Customer affected?:
ISV affected?:
Waiting Support:
Flags outvoted (downgraded) after PO Review:
Ticket number: 2023010621000137
Bug group (optional): Security
Customer ID: 07312
Max CVSS v3 score: 8.1 (CVSS:v3.1:AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)


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Comment 1 Arvid Requate univentionstaff 2023-01-06 13:57:41 CET
Backporting the changes to Samba 4.10.18 may not be possible
and updating Samba to anything higher than 4.13.7 (the version
contained in the original UCS 5.0-0 major release) would break
the package update chain.

The upstream advisory for the first CVE explains how to fix this.
I've adapted the upstream advice for UCS and published it as help article:

https://help.univention.com/t/20961

or

https://help.univention.com/t/samba-deprecates-rc4-hmac-cipher-for-kerberos-session-keys
Comment 2 Stephan Hendl 2023-01-06 14:49:09 CET
Since we still use UCS-4.4 and AD Member Mode is this bug relevant for us?
Comment 3 Arvid Requate univentionstaff 2023-01-06 21:17:31 CET
The first two vulnerabilities are related to Samba/AD KDC behavior.
In AD-Member configuration, the UCS server will use the Micosoft AD KDC
instead, for which Microsoft has issued updates addressing the issues.

The vulnerability https://www.samba.org/samba/security/CVE-2022-38023.html
also affects fileservers as far as I understand, and as described in that
advisory, the Samba patch just changes teh default for two configuration
options. This can also be done manually by running

ucr set samba/global/options/"reject md5 servers"=yes \
        samba/global/options/"reject md5 clients"=yes
/etc/init.d/samba restart

on all UCS servers running Samba.