The Windows Firewall must block unicast response to multicast or broadcast messages for the Public Profile.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17441	WN08-FW-000023	SV-48401r1_rule	ECSC-1	Medium

Description
A firewall provides a line of defense against attack. To be effective, it must be enabled and properly configured. Unicast responses to multicast or broadcast messages for a public network will be blocked. This helps minimize the risk of an attacker using broadcast or multicast traffic to deliver malicious payloads.

STIG	Date
Windows 8 Security Technical Implementation Guide	2013-07-03

Details

Check Text ( C-45070r2_chk )
If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Subkey: \Software\Policies\Microsoft\WindowsFirewall\PublicProfile\ Value Name: DisableUnicastResponsesToMulticastBroadcast Type: REG_DWORD Value: 1 Note: If a third-party firewall is used, document this with the IAO and mark the Windows firewall settings as NA. A comparable setting must still be implemented. The Secure Remote Computing STIGs may contain additional requirements for systems used remotely.

Check Text ( C-45070r2_chk )

If the following registry value does not exist or is not configured as specified, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE
Subkey: \Software\Policies\Microsoft\WindowsFirewall\PublicProfile\

Value Name: DisableUnicastResponsesToMulticastBroadcast

Type: REG_DWORD
Value: 1

Note: If a third-party firewall is used, document this with the IAO and mark the Windows firewall settings as NA. A comparable setting must still be implemented. The Secure Remote Computing STIGs may contain additional requirements for systems used remotely.

Fix Text (F-41532r1_fix)
Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Windows Firewall with Advanced Security -> Windows Firewall with Advanced Security -> Windows Firewall Properties (this link will be in the right pane) -> Public Profile Tab -> Settings (select Customize) -> Unicast response, "Allow unicast response" to "No".