Vulnerability Discussion
Windows Defender SmartScreen helps protect systems from programs downloaded from the internet that may be malicious. Enabling Windows Defender SmartScreen will warn or prevent users from running potentially malicious programs.
Check
This is applicable to unclassified systems, for other systems this is NA.
If the following registry values do not exist or are not configured as specified, this is a finding:
Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SOFTWARE\Policies\Microsoft\Windows\System\
Value Name: EnableSmartScreen
Value Type: REG_DWORD
Value: 0x00000001 (1)
And
Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SOFTWARE\Policies\Microsoft\Windows\System\
Value Name: ShellSmartScreenLevel
Value Type: REG_SZ
Value: Block
v1607 LTSB:
Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SOFTWARE\Policies\Microsoft\Windows\System\
Value Name: EnableSmartScreen
Value Type: REG_DWORD
Value: 0x00000001 (1)
v1507 LTSB:
Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SOFTWARE\Policies\Microsoft\Windows\System\
Value Name: EnableSmartScreen
Value Type: REG_DWORD
Value: 0x00000002 (2)
Fix
Configure the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> File Explorer >> "Configure Windows Defender SmartScreen" to "Enabled" with "Warn and prevent bypass" selected.
Windows 10 includes duplicate policies for this setting. It can also be configured under Computer Configuration >> Administrative Templates >> Windows Components >> Windows Defender SmartScreen >> Explorer.
v1607 LTSB:
Configure the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> File Explorer >> "Configure Windows SmartScreen" to "Enabled". (Selection options are not available.)
v1507 LTSB:
Configure the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> File Explorer >> "Configure Windows SmartScreen" to "Enabled" with "Require approval from an administrator before running downloaded unknown software" selected.