IPv6 TCP data retransmissions must be configured to prevent resources from becoming exhausted.

From Windows Server 2008 R2 Domain Controller Security Technical Implementation Guide

Associated with: CCI-002385

SV-32450r2_rule IPv6 TCP data retransmissions must be configured to prevent resources from becoming exhausted.

Vulnerability discussion

Configuring Windows to limit the number of times that IPv6 TCP retransmits unacknowledged data segments before aborting the attempt helps prevent resources from becoming exhausted.

Check content

Analyze the system using the Security Configuration and Analysis snap-in. Expand the Security Configuration and Analysis tree view. Navigate to Local Policies >> Security Options. If the value for "MSS: (TcpMaxDataRetransmissions IPv6) How many times unacknowledged data is retransmitted (3 recommended, 5 is default)" is not set to "3" or less, this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\ Value Name: TcpMaxDataRetransmissions Type: REG_DWORD Value: 3 (or less)

Fix text

Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "MSS: (TcpMaxDataRetransmissions IPv6) How many times unacknowledged data is retransmitted (3 recommended, 5 is default)" to "3" or less.

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