Exchange must provide mailbox databases in a highly available and redundant configuration.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-259709	EX19-MB-000234	SV-259709r942441_rule		Medium

Description
Exchange Server mailbox databases and any data contained in those mailboxes should be protected. This can be accomplished by configuring Mailbox servers and databases for high availability and site resilience. A database availability group (DAG) is a component of the Mailbox server high availability and site resilience framework built into Microsoft Exchange Server 2019. A DAG is a group of Mailbox servers that hosts a set of databases and provides automatic database-level recovery from failures that affect individual servers or databases. A DAG is a boundary for mailbox database replication and database and server switchovers and failovers. Any server in a DAG can host a copy of a mailbox database from any other server in the DAG. When a server is added to a DAG, it works with the other servers in the DAG to provide automatic recovery from failures that affect mailbox databases, such as a disk, server, or network failure.

Description

Exchange Server mailbox databases and any data contained in those mailboxes should be protected. This can be accomplished by configuring Mailbox servers and databases for high availability and site resilience. A database availability group (DAG) is a component of the Mailbox server high availability and site resilience framework built into Microsoft Exchange Server 2019. A DAG is a group of Mailbox servers that hosts a set of databases and provides automatic database-level recovery from failures that affect individual servers or databases. A DAG is a boundary for mailbox database replication and database and server switchovers and failovers. Any server in a DAG can host a copy of a mailbox database from any other server in the DAG. When a server is added to a DAG, it works with the other servers in the DAG to provide automatic recovery from failures that affect mailbox databases, such as a disk, server, or network failure.

STIG	Date
Microsoft Exchange 2019 Mailbox Server Security Technical Implementation Guide	2024-01-10

Details

Check Text ( C-63448r942439_chk )
Review the Email Domain Security Plan (EDSP). Determine if a Database Availability Group exists. From Exchange Admin Center: 1. In the pane on the left, navigate to "servers". 2. In the pane on the right, navigate to the "database availability groups" tab. 3. Verify a database availability group is configured with member servers. If two or more member servers are not listed, this is a finding. From Exchange PowerShell, run the following cmdlet: Get-DatabaseAvailabilityGroup If no DatabaseAvailabilityGroup is listed or a Database Availability Group is listed but has no member servers, this is a finding. Determine if the Exchange Mailbox databases are using redundancy. From Exchange Admin Center: 1. In the pane on the left, navigate to "servers". 2. In the pane on the right, navigate to the "databases" tab. 3. For each database, check the column "SERVERS WITH COPIES". Unless specified in the EDSP, if the "SERVERS WITH COPIES" column does not have two or more servers listed, this is a finding. From Exchange PowerShell, run the following cmdlet: Get-MailboxDatabaseCopyStatus -Identity Unless specified in the EDSP, if the output of this cmdlet does not show more than one copy, this is a finding.

Check Text ( C-63448r942439_chk )

Review the Email Domain Security Plan (EDSP).

Determine if a Database Availability Group exists.
From Exchange Admin Center:
1. In the pane on the left, navigate to "servers".
2. In the pane on the right, navigate to the "database availability groups" tab.
3. Verify a database availability group is configured with member servers.

If two or more member servers are not listed, this is a finding.

From Exchange PowerShell, run the following cmdlet:

Get-DatabaseAvailabilityGroup

If no DatabaseAvailabilityGroup is listed or a Database Availability Group is listed but has no member servers, this is a finding.

Determine if the Exchange Mailbox databases are using redundancy.
From Exchange Admin Center:
1. In the pane on the left, navigate to "servers".
2. In the pane on the right, navigate to the "databases" tab.
3. For each database, check the column "SERVERS WITH COPIES".

Unless specified in the EDSP, if the "SERVERS WITH COPIES" column does not have two or more servers listed, this is a finding.

From Exchange PowerShell, run the following cmdlet:

Get-MailboxDatabaseCopyStatus -Identity

Unless specified in the EDSP, if the output of this cmdlet does not show more than one copy, this is a finding.

Fix Text (F-63356r942440_fix)
Update the EDSP to specify how Exchange Mailbox databases use redundancy. Add two or more Mailbox servers to the database availability group. Add a database copy to one or more member servers within the database availability group.