Attachment 15018 Details for Bug 13834 – advisory with CVE (v5)

advisory with CVE (v5)

CVE-2019-3870-advisory-05.txt (text/plain), 2.65 KB, created by Andrew Bartlett on 2019-03-29 04:26:32 UTC

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Creator: Andrew Bartlett

Created: 2019-03-29 04:26:32 UTC

Size: 2.65 KB

patch

obsolete

>===========================================================
>== Subject:     World writable files in Samba AD DC private/ dir
>==
>== CVE ID#:     CVE-2019-3870
>==
>== Versions:    Samba 4.9 and later
>==
>== Summary:     During the provision of a new Active Directory
>                DC, some files in the private/ directory are
>		created world-writable.
>===========================================================
>
>===========
>Description
>===========
>
>During the creation of a new Samba AD DC, files are created in a the
>private/ subdirectory of our install location.  This directory is
>typically mode 0700, that is owner (root) only access.  However in
>some upgraded installations it will have other permissions, such as
>0755, because this was the default before Samba 4.8.
>
>Within this directory files are created with mode 0666,
>that is world-writable, including a sample krb5.conf and the list of
>DNS names and servicePrincipalName values to update.
>
>==================
>Patch Availability
>==================
>
>Patches addressing both these issues have been posted to:
>
>    http://www.samba.org/samba/security/
>
>Additionally, Samba 4.9.6 and 4.10.2 have been issued
>as security releases to correct the defect.  Samba administrators are
>advised to upgrade to these releases or apply the patch as soon
>as possible.
>
>==================
>CVSSv3 calculation
>==================
>
>CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
>
>This score is calculated based on modification to the dns_update_list or
>spn_update_list files in a default configuration.
>
>Administrators who rely on these files in other ways might have a higher score.
>For example, the sample krb5.conf might be read as input to Kerberos tools or
>used as the system-wide krb5.conf (potentially via a symlink).
>
>===============================
>Required steps (and workaround)
>===============================
>
>Upgrading Samba will not change the file or directory permissions for
>an existing installation, it will just avoid the issue for new
>installations.
>
>Assuming Samba is installed in the default location as root run:
>
> chmod 0700 /usr/local/samba/private
>
>The private directory can be found in the listing from
> smbd -b| grep PRIVATE_DIR
>
>Alternatively remove world-write permission from any files with:
> chmod o-w /usr/local/samba/private/*
>
>=======
>Credits
>=======
>
>Originally reported by BjÃ¶rn Baumbach of the Samba Team and SerNet.
>
>Patches provided by Andrew Bartlett of the Samba Team and Catalyst,
>advisory written by Andrew Bartlett of the Samba Team and Catalyst.
>
>==========================================================
>== Our Code, Our Bugs, Our Responsibility.
>== The Samba Team
>==========================================================
>

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dbagnall: review+
abartlet: review+

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