Exchange nonexistent recipients must not be blocked.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-221236 | EX16-ED-000370 | SV-221236r961161_rule | CCI-001308 | medium |
| Description | ||||
| Spam originators, in an effort to refine mailing lists, sometimes use a technique where they first create fictitious names and then monitor rejected emails for non-existent recipients. Those not rejected are deemed to exist and are used in future spam mailings. To prevent this disclosure of existing email accounts to spammers, email to nonexistent recipients must not be blocked. Instead, it is recommended that all messages be received, then evaluated and disposed of without enabling the sender to determine existent vs. nonexistent recipients. | ||||
| STIG | Date | |||
| Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide | 2024-12-06 | |||
Related Frameworks
1 mapping across 3 frameworks
Related Frameworks
SCF0 mappings
No source states a mapping between these directly.
Also reachable in 3 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.
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
- SCF Secure Traceability Relationship Mapping (STRM)2026.2equal to
NIST 800-530 mappings
No source states a mapping between these directly.
Also reachable in 2 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.
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
- DISA CCI List2025-01-23equal to(normalised)
CCI1 mapping
CCI-001308
1.00
- DISA STIG Benchmark (XCCDF)V2R6intersects(normalised)
Details
Check Text (C-221236r961161_chk)
Note: If third-party anti-spam product is being used, the anti-spam product must be configured to meet the requirement.
Open the Exchange Management Shell and enter the following command:
Get-RecipientFilterConfig | Select Name, RecipientValidationEnabled
If the value of "RecipientValidationEnabled" is not set to "False", this is a finding.
Fix Text (F-22940r411835_fix)
Open the Exchange Management Shell and enter the following command:
Set-RecipientFilterConfig -RecipientValidationEnabled $false