Exchange Mail quota settings must not restrict receiving mail.

From Microsoft Exchange 2016 Mailbox Server Security Technical Implementation Guide

Associated with: CCI-001094

SV-95383r1_rule Exchange Mail quota settings must not restrict receiving mail.

Vulnerability discussion

Mail quota settings control the maximum sizes of a user’s mailbox and the system’s response if these limits are exceeded. Mailbox data that is not monitored against a quota increases the risk of mail loss due to filled disk space, which can also render the system unavailable.Failure to allow mail receipt may impede users from receiving mission-critical data.

Check content

Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase | Select Name, Identity, ProhibitSendReceiveQuota If the value of "ProhibitSendReceiveQuota" is not set to "Unlimited", this is a finding. or If the value of "ProhibitSendReceiveQuota" is set to an alternate value and has signoff and risk acceptance in the EDSP, this is not a finding.

Fix text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase -Identity <'IdentityName'> -ProhibitSendReceiveQuota Unlimited Note: The value must be in single quotes. or Enter the value as identified by the EDSP that has obtained a signoff with risk acceptance.

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