Check: EX16-ED-000510
Microsoft Exchange 2016 Edge Transport Server STIG:
EX16-ED-000510
(in versions v2 r5 through v1 r1)
Title
The Exchange Simple Mail Transfer Protocol (SMTP) IP Allow List Connection filter must be enabled. (Cat II impact)
Discussion
Email system availability depends in part on best practice strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to availability impacts. Filters that govern inbound email evaluation can significantly reduce spam, phishing, and spoofed emails. Filters for messages from blank senders, known spammers, or zero-day attack modifications must be enabled to be effective. Having items identified in the Allow List causes other spam evaluation steps to be bypassed and therefore should be used only with an abundance of caution. If spammers were to learn of entries in the Allow List, it could enable them to plan a denial of service attack (or other attack) by spoofing that source.
Check Content
Open the Exchange Management Shell and enter the following command: Get-IPAllowListConfig | Select Name, Enabled If the value for "Enabled" is not set to "True", this is a finding.
Fix Text
Open the Exchange Management Shell and enter the following command: Set-IPAllowListConfig -Enabled $true
Additional Identifiers
Rule ID: SV-221247r879653_rule
Vulnerability ID: V-221247
Group Title: SRG-APP-000261
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-001308 |
The information system automatically updates spam protection mechanisms. |
Controls
Number | Title |
---|---|
SI-8 (2) |
Automatic Updates |