Ensure automatic forwarding to external domains is blocked in outbound spam policies

높음레벨 1자동m365

설명

Attackers who compromise a mailbox commonly add forwarding rules to exfiltrate mail. Prints the number of outbound spam filter policies whose AutoForwardingMode is not Off (expected 0). Requires an already-connected Exchange Online session: Install-Module ExchangeOnlineManagement; Connect-ExchangeOnline (View-Only Organization Management is sufficient). The audit throws if no session exists.

점검 방법

감사 방식: 셸 명령

shell

$ErrorActionPreference = 'Stop'; if (-not (Get-Command Get-ConnectionInformation -ErrorAction SilentlyContinue) -or -not (Get-ConnectionInformation)) { throw 'Not connected: run Connect-ExchangeOnline first' }; $bad = @(Get-HostedOutboundSpamFilterPolicy -ErrorAction Stop | Where-Object { "$($_.AutoForwardingMode)" -ne 'Off' }); $bad.Count

예상 출력: 0

조치 방법

조치 방식: 가이드 또는 인프라 패치

Set-HostedOutboundSpamFilterPolicy -Identity Default -AutoForwardingMode Off (and for each custom policy). Allow approved exceptions with a dedicated policy scoped to specific senders.

속성

운영 체제: 모두
태그: m365mail-flow
참고 자료: CIS Microsoft 365 Foundations Benchmark v7.0.0 - Exchange Online Protection / Outbound spam policy - automatic forwarding (verify section number for your release)

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감사 권한이 있는 시스템에서 실행하세요. 스캔은 읽기 전용입니다.

shell

tmaegis scan --target m365