Receive Connector connections count must be controlled.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
Exch-HB-202	Exch-HB-202	Exch-HB-202_rule		Low

Description
Email system availability depends in part on best practices strategies for setting tuning. This configuration controls the maximum number of simultaneous inbound connections allowed to the server. By default, the number of simultaneous inbound connections is unlimited. If a limit is set and is too low, the connections pool may get filled. If attackers perceive there is a limit, they could deny service to the Simple Mail Transfer Protocol (SMTP) server using a limited connection count.

Description

Email system availability depends in part on best practices strategies for setting tuning. This configuration controls the maximum number of simultaneous inbound connections allowed to the server. By default, the number of simultaneous inbound connections is unlimited. If a limit is set and is too low, the connections pool may get filled. If attackers perceive there is a limit, they could deny service to the Simple Mail Transfer Protocol (SMTP) server using a limited connection count.

STIG	Date
Microsoft Exchange 2010 Hub Transport Server Role	2012-05-31

Details

Check Text ( C-_chk )
Obtain the Email Domain Security Plan (EDSP) and locate the "Maximum Inbound connections" value. Open the Exchange Management Shell and enter the following command. Get-ReceiveConnector \| Select Name, Identity, MaxInboundConnection If the value of "MaxInboundConnection" is set to 5000 or less, this is not a finding. If "MaxInboundConnection" is set to more than 5000, and has signoff and risk acceptance in the EDSP, this is not a finding.

Check Text ( C-_chk )

Obtain the Email Domain Security Plan (EDSP) and locate the "Maximum Inbound connections" value.

Open the Exchange Management Shell and enter the following command.

Get-ReceiveConnector | Select Name, Identity, MaxInboundConnection

If the value of "MaxInboundConnection" is set to 5000 or less, this is not a finding.

If "MaxInboundConnection" is set to more than 5000, and has signoff and risk acceptance in the EDSP, this is not a finding.

Fix Text (F-_fix)
Open the Exchange Management Shell and enter the following command. Set-ReceiveConnector -Identity <'ReceiveConnector'> -MaxInboundConnection 5000 or other value as identified by the Email Domain Security Plan.