Finding ID | Version | Rule ID | IA Controls | Severity |
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V-80553 | EX16-ED-000370 | SV-95263r1_rule | Medium |
Description |
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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 |
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Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide | 2018-08-28 |
Check Text ( C-80285r1_chk ) |
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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-87405r1_fix) |
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Open the Exchange Management Shell and enter the following command: Set-RecipientFilterConfig -RecipientValidationEnabled $false |