Ensure 'MSS: (TcpMaxDataRetransmissions IPv6) How many times unacknowledged data is retransmitted' is set to 'Enabled: 3'

中レベル 2自動windows

説明

This setting controls the number of times that TCP retransmits an individual data segment (non-connect segment) before the connection is aborted. The retransmission time-out is doubled with each successive retransmission on a connection. It is reset when responses resume. The base time-out value is dynamically determined by the measured round-trip time on the connection. The recommended state for this setting is: Enabled: 3.

チェック方法

監査方法: Windows レジストリ

registry

$bad = @(); $v = (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters' -Name 'TcpMaxDataRetransmissions' -ErrorAction SilentlyContinue).'TcpMaxDataRetransmissions'; if (-not ($null -ne $v -and @(3) -contains [int64]$v)) { $bad += 'TcpMaxDataRetransmissions=' + $v }; if ($bad.Count -eq 0) { 'compliant' } else { 'non-compliant: ' + ($bad -join ', ') }

期待される出力: compliant

修正方法

修正方法: シェルコマンド

shell

if (-not (Test-Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters')) { New-Item -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters' -Force | Out-Null }; New-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters' -Name 'TcpMaxDataRetransmissions' -Value 3 -PropertyType DWord -Force | Out-Null

プロパティ

オペレーティングシステム: windows-server-2025-dc, windows-server-2025-ms
タグ: cis-convertedregistrywindows
参照: CIS Microsoft Windows Server 2025 Benchmark v2.1.0 - 18.5.9

このホストをチェック

監査が許可されているマシンで実行してください。スキャンは読み取り専用です。

shell

tmaegis scan --target windows --level 2