Exchange Receive connectors must control the number of recipients per message.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-221229 | EX16-ED-000300 | SV-221229r961155_rule | CCI-001095 | medium |
| Description | ||||
| Email system availability depends in part on best practice strategies for setting tuning configurations. This configuration controls the maximum number of recipients who will receive a copy of a message at one time. This tunable value is related to throughput capacity and can enable the ability to optimize message delivery. Note: There are two types of default Receive connecters: "Client Servername" accepts SMTP connections from all non-MAPI clients, such as POP and IMAP. As POP and IMAP are not authorized for use in DoD, these should not be present. Their default value for MaxRecipientsPerMessage is 200. IMAP Secure is not restricted and may be configured. "Default Servername" accepts connections from other mailbox servers and any Edge Transport servers. Their default value for MaxRecipientsPerMessage is 5000. | ||||
| STIG | Date | |||
| Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide | 2024-12-06 | |||
Related Frameworks
1 mapping across 4 frameworks
Related Frameworks
SCF0 mappings
No source states a mapping between these directly.
Also reachable in 3 hops (2) derived by us, not asserted by any source
Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- SCF Secure Traceability Relationship Mapping (STRM)2026.2intersects
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- SCF Secure Traceability Relationship Mapping (STRM)2026.2intersects
NIST 800-530 mappings
No source states a mapping between these directly.
Also reachable in 2 hops (13) derived by us, not asserted by any source
Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)V1R1our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)V1R1intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)2our copyintersects(normalised)DISA STIG Benchmark (XCCDF)V2R9our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)2intersects(normalised)DISA STIG Benchmark (XCCDF)V2R9intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)V1R1our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)V1R1intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)V10R7our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)V10R7intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)V1R1our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)V1R1intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)V3R3our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)V3R3intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)1our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)1intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)1our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)1intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)V2R1our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)V2R1intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA STIG Benchmark (XCCDF)V10R7our copyintersects(normalised)
- DISA STIG Benchmark (XCCDF)V10R7intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
+3 more (top 10 by confidence shown)
CCI1 mapping
CCI-001095
1.00
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
NIST CSF 2.00 mappings
No source states a mapping between these directly.
Also reachable in 4 hops (1) derived by us, not asserted by any source
Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.
PR.IR-04
0.50
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- SCF Secure Traceability Relationship Mapping (STRM)2026.2intersects
- NIST OLIR Informative ReferenceOLIR 153 (2025-04-07)intersects(normalised)SCF Focal Document mapping (catalog)SCF 2026.2 focalintersects(normalised)
Details
Check Text (C-221229r961155_chk)
Review the Email Domain Security Plan (EDSP).
Determine the Maximum Recipients per Message value.
Open the Exchange Management Shell and enter the following command:
Get-ReceiveConnector | Select Name, Identity, MaxRecipientsPerMessage
For each receive connector, if the value of "MaxRecipientsPerMessage" is not set to "5000", this is a finding.
or
If the value of "MaxRecipientsPerMessage" is set to a value other than "5000" and has signoff and risk acceptance in the EDSP, this is not a finding.
Fix Text (F-22933r411814_fix)
Update the EDSP to reflect the Maximum Recipients per Message value.
Open the Exchange Management Shell and enter the following command:
Set-ReceiveConnector -Identity <'IdentityName'> -MaxRecipientsPerMessage 5000
Note: The <IdentityName> value must be in single quotes.
or
The value as identified by the EDSP that has obtained a signoff with risk acceptance.
Repeat the procedure for each receive connector.