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Diffstat (limited to 'docs-xml/smbdotconf/logon/rejectmd5clients.xml')
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diff --git a/docs-xml/smbdotconf/logon/rejectmd5clients.xml b/docs-xml/smbdotconf/logon/rejectmd5clients.xml new file mode 100644 index 0000000..fe7701d --- /dev/null +++ b/docs-xml/smbdotconf/logon/rejectmd5clients.xml @@ -0,0 +1,110 @@ +<samba:parameter name="reject md5 clients" + context="G" + type="boolean" + deprecated="1" + xmlns:samba="http://www.samba.org/samba/DTD/samba-doc"> +<description> + <para> + This option is deprecated and will be removed in a future release, + as it is a security problem if not set to "yes" (which will be + the hardcoded behavior in the future). + </para> + + <para>This option controls whether the netlogon server (currently + only in 'active directory domain controller' mode), will + reject clients which does not support NETLOGON_NEG_SUPPORTS_AES.</para> + + <para>Support for NETLOGON_NEG_SUPPORTS_AES was added in Windows + starting with Server 2008R2 and Windows 7, it's available in Samba + starting with 4.0, however third party domain members like NetApp ONTAP + still uses RC4 (HMAC-MD5), see + <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">https://www.samba.org/samba/security/CVE-2022-38023.html</ulink> + for more details. + </para> + + <para>The default changed from 'no' to 'yes', with the patches for + <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">CVE-2022-38023</ulink> + see <ulink url="https://bugzilla.samba.org/show_bug.cgi?id=15240">https://bugzilla.samba.org/show_bug.cgi?id=15240</ulink>. + </para> + + <para><emphasis>Avoid using this option!</emphasis> Use an explicit per machine account + '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT"/>' instead! + Which is available with the patches for + <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">CVE-2022-38023</ulink> + see <ulink url="https://bugzilla.samba.org/show_bug.cgi?id=15240">https://bugzilla.samba.org/show_bug.cgi?id=15240</ulink>. + </para> + + <para> + Samba will log an error in the log files at log level 0 + if legacy a client is rejected or allowed without an explicit, + '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT">no</smbconfoption>' option + for the client. The message will indicate + the explicit '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT">no</smbconfoption>' + line to be added, if the legacy client software requires it. (The log level can be adjusted with + '<smbconfoption name="CVE_2022_38023:error_debug_level">1</smbconfoption>' + in order to complain only at a higher log level). + </para> + + <para>This allows admins to use "no" only for a short grace period, + in order to collect the explicit + '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT">no</smbconfoption>' options.</para> + + <para>When set to 'yes' this option overrides the + '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT"/>' and + '<smbconfoption name="allow nt4 crypto"/>' options and implies + '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT">no</smbconfoption>'. + </para> +</description> + +<value type="default">yes</value> +</samba:parameter> + +<samba:parameter name="server reject md5 schannel:COMPUTERACCOUNT" + context="G" + type="string" + xmlns:samba="http://www.samba.org/samba/DTD/samba-doc"> +<description> + + <para>If you still have legacy domain members or trusted domains, + which required "reject md5 clients = no" before, + it is possible to specify an explicit exception per computer account + by setting 'server reject md5 schannel:COMPUTERACCOUNT = no'. + Note that COMPUTERACCOUNT has to be the sAMAccountName value of + the computer account (including the trailing '$' sign). + </para> + + <para> + Samba will log a complaint in the log files at log level 0 + about the security problem if the option is set to "no", + but the related computer does not require it. + (The log level can be adjusted with + '<smbconfoption name="CVE_2022_38023:warn_about_unused_debug_level">1</smbconfoption>' + in order to complain only at a higher log level). + </para> + + <para> + Samba will log a warning in the log files at log level 5 + if a setting is still needed for the specified computer account. + </para> + + <para> + See <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">CVE-2022-38023</ulink>, + <ulink url="https://bugzilla.samba.org/show_bug.cgi?id=15240">https://bugzilla.samba.org/show_bug.cgi?id=15240</ulink>. + </para> + + <para>This option overrides the <smbconfoption name="reject md5 clients"/> option.</para> + + <para>When set to 'yes' this option overrides the + '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT"/>' and + '<smbconfoption name="allow nt4 crypto"/>' options and implies + '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT">no</smbconfoption>'. + </para> + + <programlisting> + server reject md5 schannel:LEGACYCOMPUTER1$ = no + server reject md5 schannel:NASBOX$ = no + server reject md5 schannel:LEGACYCOMPUTER2$ = no + </programlisting> +</description> + +</samba:parameter> |