Exchange Receive connectors must control the number of recipients chunked on a single message.

From MS Exchange 2013 Edge Transport Server Security Technical Implementation Guide

Associated with: CCI-001095

SV-84461r1_rule Exchange Receive connectors must control the number of recipients chunked on a single message.

Vulnerability discussion

Email system availability depends in part on best practice strategies for setting tuning configurations. For message size restrictions, multiple places exist to set or override inbound or outbound message size. Failure to control the configuration strategy can result in loss of data or system availability. This setting enables the administrator to enable "chunking" on received messages as they arrive at the domain. This is done so large message bodies can be relayed by the remote sender to the Receive connector in multiple, smaller chunks.

Check content

Open the Exchange Management Shell and enter the following command: Get-ReceiveConnector | Select Name, Identity, ChunkingEnabled For each Receive connector, if the value of ChunkingEnabled is not set to True, this is a finding.

Fix text

Open the Exchange Management Shell and enter the following command: Set-ReceiveConnector -Identity <'IdentityName'> -ChunkingEnabled $true Note: The value must be in quotes. Repeat the procedure for each Receive connector.

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