Title

IPv6 TCP data retransmissions must be configured to prevent resources from becoming exhausted. (Cat III impact)

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

If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\ Value Name: TcpMaxDataRetransmissions Value 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. (See "Updating the Windows Security Options File" in the STIG Overview document if MSS settings are not visible in the system's policy tools.)

Additional Identifiers

Rule ID:

Vulnerability ID: V-21956

Group Title:

Expert Comments

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