MS Windows Defender Antivirus Security Technical Implementation Guide

Version

WNDF-AV-000004

Vuln IDs

V-75153

Rule IDs

SV-89833r3_rule

This policy setting turns off Windows Defender Antivirus. If you enable this policy setting Windows Defender Antivirus does not run and computers are not scanned for malware or other potentially unwanted software. When the setting is Disabled and a third-party antivirus solution is installed, the two applications can both simultaneously try to protect the system. The two AV solutions both attempt to quarantine the same threat and will fight for access to delete the file. Users will see conflicts and the system may lock up until the two solutions finish processing. When the setting is Not Configured and a third-party antivirus solution is installed, both applications co-exist on the system without conflicts. Defender Antivirus will automatically disable itself and will enable if the third-party solution stops functioning. When the setting is Not Configured and Defender Antivirus is the only AV solution, Defender AV will run (default state) and receive definition updates. An administrator account is needed to turn off the service. A standard user cannot disable the service.

Checks: C-74945r4_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> "Turn off Windows Defender Antivirus" is set to “Not Configured”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender Criteria: If the value "DisableAntiSpyware" does not exist, this is not a finding.

Fix: F-81765r3_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> "Turn off Windows Defender Antivirus" to "Not Configured”.

b

Windows Defender AV must be configured to not exclude files for scanning.

SI-3 - Medium - CCI-001242 - V-75155 - SV-89835r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000005

Vuln IDs

V-75155

Rule IDs

SV-89835r2_rule

This policy setting allows you to disable scheduled and real-time scanning for files under the paths specified or for the fully qualified resources specified. Paths should be added under the Options for this setting. Each entry must be listed as a name value pair where the name should be a string representation of a path or a fully qualified resource name. As an example a path might be defined as: "c:\Windows" to exclude all files in this directory. A fully qualified resource name might be defined as: "C:\Windows\App.exe". The value is not used and it is recommended that this be set to 0.

Checks: C-74947r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Path Exclusions" is set to "Disabled" or "Not Configured. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Exclusions Criteria: If the value "Exclusions_Paths" does not exist, this is not a finding.

Fix: F-81767r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Path Exclusions" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to not exclude files opened by specified processes.

SI-3 - Medium - CCI-001242 - V-75157 - SV-89837r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000006

Vuln IDs

V-75157

Rule IDs

SV-89837r2_rule

This policy setting allows you to disable scheduled and real-time scanning for any file opened by any of the specified processes. The process itself will not be excluded. To exclude the process use the Path exclusion. Processes should be added under the Options for this setting. Each entry must be listed as a name value pair where the name should be a string representation of the path to the process image. Note that only executables can be excluded. For example a process might be defined as: "c:\windows\app.exe". The value is not used and it is recommended that this be set to 0.

Checks: C-74949r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Process Exclusions" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Exclusions Criteria: If the value "Exclusions_Processes" does not exist, this is not a finding.

Fix: F-81769r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Process Exclusions" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to enable the Automatic Exclusions feature.

SI-3 - Medium - CCI-001242 - V-75159 - SV-89839r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000007

Vuln IDs

V-75159

Rule IDs

SV-89839r2_rule

Allows an administrator to specify if Automatic Exclusions feature for Server SKUs should be turned off.

Checks: C-74951r2_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Turn off Auto Exclusions" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Exclusions Criteria: If the value "DisableAutoExclusions" is REG_DWORD = 0, this is not a finding.

Fix: F-81771r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Turn off Auto Exclusions" to "Disabled".

b

Windows Defender AV must be configured to disable local setting override for reporting to Microsoft MAPS.

SC-18 - Medium - CCI-001170 - V-75161 - SV-89841r2_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000008

Vuln IDs

V-75161

Rule IDs

SV-89841r2_rule

This policy setting configures a local override for the configuration to join Microsoft MAPS. This setting can only be set by Group Policy. If you enable this setting the local preference setting will take priority over Group Policy. If you disable or do not configure this setting Group Policy will take priority over the local preference setting.

Checks: C-74953r5_chk

This is applicable to unclassified systems, for other systems this is NA. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Configure local setting override for reporting to Microsoft MAPS" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Spynet Criteria: If the value "LocalSettingOverrideSpynetReporting" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81773r4_fix

This is applicable to unclassified systems, for other systems this is NA. Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Configure local setting override for reporting to Microsoft MAPS" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to check in real time with MAPS before content is run or accessed.

SI-3 - Medium - CCI-001242 - V-75163 - SV-89843r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000009

Vuln IDs

V-75163

Rule IDs

SV-89843r2_rule

This feature ensures the device checks in real time with the Microsoft Active Protection Service (MAPS) before allowing certain content to be run or accessed. If this feature is disabled the check will not occur which will lower the protection state of the device. Enabled - The Block at First Sight setting is turned on. Disabled - The Block at First Sight setting is turned off. This feature requires these Group Policy settings to be set as follows: MAPS -> The "Join Microsoft MAPS" must be enabled or the "Block at First Sight" feature will not function. MAPS -> The "Send file samples when further analysis is required" should be set to 1 (Send safe samples) or 3 (Send all samples). Setting to 0 (Always Prompt) will lower the protection state of the device. Setting to 2 (Never send) means the "Block at First Sight" feature will not function. Real-time Protection -> The "Scan all downloaded files and attachments" policy must be enabled or the "Block at First Sight" feature will not function. Real-time Protection -> Do not enable the "Turn off real-time protection" policy or the "Block at First Sight" feature will not function.

Checks: C-74957r3_chk

This is applicable to unclassified systems, for other systems this is NA. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Configure the 'Block at First Sight' feature" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Spynet Criteria: If the value "DisableBlockAtFirstSeen" is REG_DWORD = 0, this is not a finding.

Fix: F-81775r3_fix

This is applicable to unclassified systems, for other systems this is NA. Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Configure the 'Block at First Sight' feature" to "Enabled".

b

Windows Defender AV must be configured to join Microsoft MAPS.

SC-18 - Medium - CCI-001170 - V-75167 - SV-89847r2_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000010

Vuln IDs

V-75167

Rule IDs

SV-89847r2_rule

This policy setting allows you to join Microsoft MAPS. Microsoft MAPS is the online community that helps you choose how to respond to potential threats. The community also helps stop the spread of new malicious software infections. You can choose to send basic or additional information about detected software. Additional information helps Microsoft create new definitions and help it to protect your computer. This information can include things like location of detected items on your computer if harmful software was removed. The information will be automatically collected and sent. In some instances personal information might unintentionally be sent to Microsoft. However Microsoft will not use this information to identify you or contact you. Possible options are: (0x0) Disabled (default) (0x1) Basic membership (0x2) Advanced membership Basic membership will send basic information to Microsoft about software that has been detected including where the software came from the actions that you apply or that are applied automatically and whether the actions were successful. Advanced membership in addition to basic information will send more information to Microsoft about malicious software spyware and potentially unwanted software including the location of the software file names how the software operates and how it has impacted your computer. If you enable this setting you will join Microsoft MAPS with the membership specified. If you disable or do not configure this setting you will not join Microsoft MAPS. In Windows 10 Basic membership is no longer available so setting the value to 1 or 2 enrolls the device into Advanced membership.

Checks: C-74959r3_chk

This is applicable to unclassified systems, for other systems this is NA. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Join Microsoft MAPS" is set to "Enabled" and "Advanced MAPS" selected from the drop down box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Spynet Criteria: If the value "SpynetReporting" is REG_DWORD = 2, this is not a finding.

Fix: F-81779r3_fix

This is applicable to unclassified systems, for other systems this is NA. Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Join Microsoft MAPS" to "Enabled" and select "Advanced MAPS" from the drop down box.

b

Windows Defender AV must be configured to only send safe samples for MAPS telemetry.

SC-18 - Medium - CCI-001170 - V-75207 - SV-89887r3_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000011

Vuln IDs

V-75207

Rule IDs

SV-89887r3_rule

This policy setting configures behavior of samples submission when opt-in for MAPS telemetry is set. Possible options are: (0x0) Always prompt (0x1) Send safe samples automatically (0x2) Never send (0x3) Send all samples automatically.

Checks: C-74999r3_chk

This is applicable to unclassified systems, for other systems this is NA. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Send file samples when further analysis is required" is set to "Enabled" and "Send safe samples" selected from the drop down box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Spynet Criteria: If the value "SubmitSamplesConsent" is REG_DWORD = 1, this is not a finding.

Fix: F-81859r4_fix

This is applicable to unclassified systems, for other systems this is NA. Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> MAPS -> "Send file samples when further analysis is required" to "Enabled" and select "Send safe samples" from the drop down box.

b

Windows Defender AV must be configured for protocol recognition for network protection.

SI-3 - Medium - CCI-001242 - V-75209 - SV-89889r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000012

Vuln IDs

V-75209

Rule IDs

SV-89889r2_rule

This policy setting allows you to configure protocol recognition for network protection against exploits of known vulnerabilities. If you enable or do not configure this setting protocol recognition will be enabled. If you disable this setting protocol recognition will be disabled.

Checks: C-75001r10_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Network Inspection System -> "Turn on protocol recognition" is set to "Enabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\NIS Criteria: If the value "DisableProtocolRecognition" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81819r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Network Inspection System -> "Turn on protocol recognition" to "Enabled" or "Not Configured".

b

Windows Defender AV must be configured to not allow local override of monitoring for file and program activity.

SC-18 - Medium - CCI-001695 - V-75211 - SV-89891r2_rule

RMF Control

SC-18

Severity

M

CCI

CCI-001695

Version

WNDF-AV-000013

Vuln IDs

V-75211

Rule IDs

SV-89891r2_rule

This policy setting configures a local override for the configuration of monitoring for file and program activity on your computer. This setting can only be set by Group Policy. If you enable this setting the local preference setting will take priority over Group Policy. If you disable or do not configure this setting Group Policy will take priority over the local preference setting.

Checks: C-75003r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for monitoring file and program activity on your computer" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "LocalSettingOverrideDisableOnAccessProtection" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81821r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for monitoring file and program activity on your computer" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to not allow override of monitoring for incoming and outgoing file activity.

SC-18 - Medium - CCI-001695 - V-75213 - SV-89893r2_rule

RMF Control

SC-18

Severity

M

CCI

CCI-001695

Version

WNDF-AV-000014

Vuln IDs

V-75213

Rule IDs

SV-89893r2_rule

This policy setting configures a local override for the configuration of monitoring for incoming and outgoing file activity. This setting can only be set by Group Policy. If you enable this setting the local preference setting will take priority over Group Policy. If you disable or do not configure this setting Group Policy will take priority over the local preference setting.

Checks: C-75005r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for monitoring for incoming and outgoing file activity" is set to "Disabled" or "Not Configure". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "LocalSettingOverrideRealtimeScanDirection" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81823r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for monitoring for incoming and outgoing file activity" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to not allow override of scanning for downloaded files and attachments.

SC-18 - Medium - CCI-001169 - V-75215 - SV-89895r2_rule

RMF Control

SC-18

Severity

M

CCI

CCI-001169

Version

WNDF-AV-000015

Vuln IDs

V-75215

Rule IDs

SV-89895r2_rule

This policy setting configures a local override for the configuration of scanning for all downloaded files and attachments. This setting can only be set by Group Policy. If you enable this setting the local preference setting will take priority over Group Policy. If you disable or do not configure this setting Group Policy will take priority over the local preference setting.

Checks: C-75007r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for scanning all downloaded files and attachments" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "LocalSettingOverrideDisableIOAVProtection" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81825r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for scanning all downloaded files and attachments" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to not allow override of behavior monitoring.

SC-18 - Medium - CCI-001170 - V-75217 - SV-89897r2_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000016

Vuln IDs

V-75217

Rule IDs

SV-89897r2_rule

This policy setting configures a local override for the configuration of behavior monitoring. This setting can only be set by Group Policy. If you enable this setting the local preference setting will take priority over Group Policy. If you disable or do not configure this setting Group Policy will take priority over the local preference setting.

Checks: C-75009r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for turn on behavior monitoring" is set to "Disabled" or "Not Configure". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "LocalSettingOverrideDisableBehaviorMonitoring" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81827r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override for turn on behavior monitoring" to "Disabled" or "Not Configured".

b

Windows Defender AV Group Policy settings must take priority over the local preference settings.

SI-3 - Medium - CCI-001242 - V-75219 - SV-89899r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000017

Vuln IDs

V-75219

Rule IDs

SV-89899r2_rule

This policy setting configures a local override for the configuration to turn on real-time protection. This setting can only be set by Group Policy. If you enable this setting the local preference setting will take priority over Group Policy. If you disable or do not configure this setting Group Policy will take priority over the local preference setting.

Checks: C-75011r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override to turn on real-time protection" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "LocalSettingOverrideDisableRealtimeMonitoring" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81829r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure local setting override to turn on real-time protection" to "Disabled" or "Not Configured".

b

Windows Defender AV must monitor for incoming and outgoing files.

SI-3 - Medium - CCI-001242 - V-75221 - SV-89901r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000018

Vuln IDs

V-75221

Rule IDs

SV-89901r2_rule

This policy setting allows you to configure monitoring for incoming and outgoing files without having to turn off monitoring entirely. It is recommended for use on servers where there is a lot of incoming and outgoing file activity but for performance reasons need to have scanning disabled for a particular scan direction. The appropriate configuration should be evaluated based on the server role. Note that this configuration is only honored for NTFS volumes. For any other file system type full monitoring of file and program activity will be present on those volumes. The options for this setting are mutually exclusive: 0 = Scan incoming and outgoing files (default) 1 = Scan incoming files only 2 = Scan outgoing files only Any other value or if the value does not exist resolves to the default (0). If you enable this setting the specified type of monitoring will be enabled. If you disable or do not configure this setting monitoring for incoming and outgoing files will be enabled.

Checks: C-75013r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure monitoring for incoming and outgoing file and program activity" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "RealtimeScanDirection" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1 or 2, this is a finding.

Fix: F-81831r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Configure monitoring for incoming and outgoing file and program activity" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to monitor for file and program activity.

SI-3 - Medium - CCI-001242 - V-75223 - SV-89903r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000019

Vuln IDs

V-75223

Rule IDs

SV-89903r2_rule

This policy setting allows you to configure monitoring for file and program activity. If you enable or do not configure this setting monitoring for file and program activity will be enabled. If you disable this setting monitoring for file and program activity will be disabled.

Checks: C-75015r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Monitor file and program activity on your computer to be scanned" is set to "Enabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "DisableOnAccessProtection" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81833r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Monitor file and program activity on your computer" to "Enabled" or "Not Configured".

b

Windows Defender AV must be configured to scan all downloaded files and attachments.

SC-18 - Medium - CCI-001169 - V-75225 - SV-89905r2_rule

RMF Control

SC-18

Severity

M

CCI

CCI-001169

Version

WNDF-AV-000020

Vuln IDs

V-75225

Rule IDs

SV-89905r2_rule

This policy setting allows you to configure scanning for all downloaded files and attachments. If you enable or do not configure this setting scanning for all downloaded files and attachments will be enabled. If you disable this setting scanning for all downloaded files and attachments will be disabled.

Checks: C-75017r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Scan all downloaded files and attachments" is set to "Enabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "DisableIOAVProtection" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81835r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Scan all downloaded files and attachments" to "Enabled" or "Not Configured".

b

Windows Defender AV must be configured to always enable real-time protection.

SI-3 - Medium - CCI-001242 - V-75227 - SV-89907r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000021

Vuln IDs

V-75227

Rule IDs

SV-89907r2_rule

This policy setting turns off real-time protection prompts for known malware detection. Windows Defender Antivirus alerts you when malware or potentially unwanted software attempts to install itself or to run on your computer. If you enable this policy setting Windows Defender Antivirus will not prompt users to take actions on malware detections. If you disable or do not configure this policy setting Windows Defender Antivirus will prompt users to take actions on malware detections.

Checks: C-75019r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn off real-time protection" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "DisableRealtimeMonitoring" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81837r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn off real-time protection" to "Disabled" or "Not Configured".

b

Windows Defender AV must be configured to enable behavior monitoring.

SC-18 - Medium - CCI-001170 - V-75229 - SV-89909r2_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000022

Vuln IDs

V-75229

Rule IDs

SV-89909r2_rule

This policy setting allows you to configure behavior monitoring. If you enable or do not configure this setting behavior monitoring will be enabled. If you disable this setting behavior monitoring will be disabled.

Checks: C-75021r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn on behavior monitoring" is set to "Enabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "DisableBehaviorMonitoring" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81839r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn on behavior monitoring" to "Enabled " or "Not Configured".

b

Windows Defender AV must be configured to process scanning when real-time protection is enabled.

SI-3 - Medium - CCI-001242 - V-75231 - SV-89911r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000023

Vuln IDs

V-75231

Rule IDs

SV-89911r2_rule

This policy setting allows you to configure process scanning when real-time protection is turned on. This helps to catch malware which could start when real-time protection is turned off. If you enable or do not configure this setting a process scan will be initiated when real-time protection is turned on. If you disable this setting a process scan will not be initiated when real-time protection is turned on.

Checks: C-75023r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn on process scanning whenever real-time protection is enabled" is set to "Enabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "DisableScanOnRealtimeEnable" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81841r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> Turn on process scanning whenever real-time protection is enabled to "Enabled" or "Not Configured".

b

Windows Defender AV must be configured to scan archive files.

SI-3 - Medium - CCI-001242 - V-75233 - SV-89913r2_rule

RMF Control

SI-3

Severity

M

CCI

Version

WNDF-AV-000024

Vuln IDs

V-75233

Rule IDs

SV-89913r2_rule

This policy setting allows you to configure scans for malicious software and unwanted software in archive files such as .ZIP or .CAB files. If you enable or do not configure this setting archive files will be scanned. If you disable this setting archive files will not be scanned.

Checks: C-75025r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Scan archive files" is set to "Enabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Scan Criteria: If the value "DisableArchiveScanning" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Fix: F-81843r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Scan archive files" to "Enabled " or "Not Configured".

b

Windows Defender AV must be configured to scan removable drives.

MA-3 - Medium - CCI-000870 - V-75235 - SV-89915r2_rule

RMF Control

MA-3

Severity

M

CCI

CCI-000870

Version

WNDF-AV-000025

Vuln IDs

V-75235

Rule IDs

SV-89915r2_rule

This policy setting allows you to manage whether or not to scan for malicious software and unwanted software in the contents of removable drives such as USB flash drives when running a full scan. If you enable this setting removable drives will be scanned during any type of scan. If you disable or do not configure this setting removable drives will not be scanned during a full scan. Removable drives may still be scanned during quick scan and custom scan.

Checks: C-75027r2_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Scan removable drives" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Scan Criteria: If the value "DisableRemovableDriveScanning" is REG_DWORD = 0, this is not a finding.

Fix: F-81845r3_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Scan removable drives" to "Enabled".

b

Windows Defender AV must be configured to perform a weekly scheduled scan.

SI-3 - Medium - CCI-001241 - V-75237 - SV-89917r2_rule

RMF Control

SI-3

Severity

M

CCI

CCI-001241

Version

WNDF-AV-000026

Vuln IDs

V-75237

Rule IDs

SV-89917r2_rule

This policy setting allows you to specify the day of the week on which to perform a scheduled scan. The scan can also be configured to run every day or to never run at all. This setting can be configured with the following ordinal number values: (0x0) Every Day (0x1) Sunday (0x2) Monday (0x3) Tuesday (0x4) Wednesday (0x5) Thursday (0x6) Friday (0x7) Saturday (0x8) Never (default) If you enable this setting a scheduled scan will run at the frequency specified. If you disable or do not configure this setting a scheduled scan will run at a default frequency.

Checks: C-75029r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Specify the day of the week to run a scheduled scan" is set to "Enabled" and anything other than "Never" selected in the drop down box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Scan Criteria: If the value "ScheduleDay" is REG_DWORD = 0x8, this is a finding. Values of 0x0 through 0x7 are acceptable and not a finding.

Fix: F-81847r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Specify the day of the week to run a scheduled scan" to "Enabled " and select anything other than "Never" in the drop down box.

b

Windows Defender AV must be configured to turn on e-mail scanning.

SC-18 - Medium - CCI-001170 - V-75239 - SV-89919r2_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000027

Vuln IDs

V-75239

Rule IDs

SV-89919r2_rule

This policy setting allows you to configure e-mail scanning. When e-mail scanning is enabled the engine will parse the mailbox and mail files according to their specific format in order to analyze the mail bodies and attachments. Several e-mail formats are currently supported for example: pst (Outlook) dbx mbx mime (Outlook Express) binhex (Mac). If you enable this setting e-mail scanning will be enabled. If you disable or do not configure this setting e-mail scanning will be disabled.

Checks: C-75031r2_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Turn on e-mail scanning" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Scan Criteria: If the value "DisableEmailScanning" is REG_DWORD = 0, this is not a finding.

Fix: F-81849r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Turn on e-mail scanning" to "Enabled".

c

Windows Defender AV spyware definition age must not exceed 7 days.

SI-3 - High - CCI-001240 - V-75241 - SV-89921r2_rule

RMF Control

SI-3

Severity

H

CCI

CCI-001240

Version

WNDF-AV-000028

Vuln IDs

V-75241

Rule IDs

SV-89921r2_rule

This policy setting allows you to define the number of days that must pass before spyware definitions are considered out of date. If definitions are determined to be out of date this state may trigger several additional actions including falling back to an alternative update source or displaying a warning icon in the user interface. By default this value is set to 14 days. If you enable this setting spyware definitions will be considered out of date after the number of days specified have passed without an update. If you disable or do not configure this setting spyware definitions will be considered out of date after the default number of days have passed without an update.

Checks: C-75033r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Define the number of days before spyware definitions are considered out of date" is set to "Enabled" and "7"or less selected in the drop down box (excluding "0", which is unacceptable). Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Signature Updates Criteria: If the value "ASSignatureDue" is REG_DWORD = 7, this is not a finding. A value of 1 - 6 is also acceptable and not a finding. A value of 0 is a finding. A value higher than 7 is a finding.

Fix: F-81851r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Define the number of days before spyware definitions are considered out of date" to "Enabled" and select "7" or less in the drop down box. Do not select a value of 0. This disables the option.

c

Windows Defender AV virus definition age must not exceed 7 days.

SI-3 - High - CCI-001240 - V-75243 - SV-89923r2_rule

RMF Control

SI-3

Severity

H

CCI

CCI-001240

Version

WNDF-AV-000029

Vuln IDs

V-75243

Rule IDs

SV-89923r2_rule

This policy setting allows you to define the number of days that must pass before virus definitions are considered out of date. If definitions are determined to be out of date this state may trigger several additional actions including falling back to an alternative update source or displaying a warning icon in the user interface. By default this value is set to 14 days. If you enable this setting virus definitions will be considered out of date after the number of days specified have passed without an update. If you disable or do not configure this setting virus definitions will be considered out of date after the default number of days have passed without an update.

Checks: C-75035r4_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Define the number of days before virus definitions are considered out of date" is set to "Enabled" and "7" or less selected in the drop down box (excluding "0", which is unacceptable). Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Signature Updates Criteria: If the value "AVSignatureDue" is REG_DWORD = 7, this is not a finding. A value of 1 - 6 is also acceptable and not a finding. A value of 0 is a finding. A value higher than 7 is a finding.

Fix: F-81853r2_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Define the number of days before virus definitions are considered out of date" to "Enabled" and select "7" or less in the drop down box. Do not select a value of 0. This disables the option.

b

Windows Defender AV must be configured to check for definition updates daily.

SI-8 - Medium - CCI-001308 - V-75245 - SV-89925r2_rule

RMF Control

SI-8

Severity

M

CCI

CCI-001308

Version

WNDF-AV-000030

Vuln IDs

V-75245

Rule IDs

SV-89925r2_rule

This policy setting allows you to specify the day of the week on which to check for definition updates. The check can also be configured to run every day or to never run at all. This setting can be configured with the following ordinal number values: (0x0) Every Day (default) (0x1) Sunday (0x2) Monday (0x3) Tuesday (0x4) Wednesday (0x5) Thursday (0x6) Friday (0x7) Saturday (0x8) Never If you enable this setting the check for definition updates will occur at the frequency specified. If you disable or do not configure this setting the check for definition updates will occur at a default frequency.

Checks: C-75037r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Specify the day of the week to check for definition updates" is set to "Enabled" and "Every Day" is selected in the drop down box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Signature Update Criteria: If the value "ScheduleDay" is REG_DWORD = 0, this is not a finding.

Fix: F-81855r3_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Specify the day of the week to check for definition updates" to "Enabled" and select "Every Day" in the drop down box.

b

Windows Defender AV must be configured for automatic remediation action to be taken for threat alert level Severe.

SC-18 - Medium - CCI-001662 - V-75247 - SV-89927r3_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000031

Vuln IDs

V-75247

Rule IDs

SV-89927r3_rule

This policy setting allows you to customize which automatic remediation action will be taken for each threat alert level. Threat alert levels should be added under the Options for this setting. Each entry must be listed as a name value pair. The name defines a threat alert level. The value contains the action ID for the remediation action that should be taken. Valid threat alert levels are: 1 = Low 2 = Medium 4 = High 5 = Severe Valid remediation action values are: 2 = Quarantine 3 = Remove 6 = Ignore

Checks: C-75039r3_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" is set to "Enabled". Click the “Show…” box option and verify the ‘Value name’ field contains a value of “5” and the ‘Value’ field contains a “2". A value of “3” in the ‘Value’ field is more restrictive and also an acceptable value. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Threats\ThreatSeverityDefaultAction Criteria: If the value "5" is REG_SZ = 2 (or 3), this is not a finding.

Fix: F-81857r3_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" to "Enabled". Select the “Show…” option box and enter "5” in the ‘Value name’ field and enter “2" in the ‘Value’ field.

b

Windows Defender AV must be configured to block executable content from email client and webmail.

SC-18 - Medium - CCI-001170 - V-77965 - SV-92661r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000032

Vuln IDs

V-77965

Rule IDs

SV-92661r1_rule

This rule blocks the following file types from being run or launched from an email seen in either Microsoft Outlook or webmail (such as Gmail.com or Outlook.com): Executable files (such as .exe, .dll, or .scr) Script files (such as a PowerShell .ps, VisualBasic .vbs, or JavaScript .js file) Script archive files

Checks: C-77575r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: BE9BA2D9-53EA-4CDC-84E5-9B1EEEE46550 Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “BE9BA2D9-53EA-4CDC-84E5-9B1EEEE46550” is REG_SZ = 1, this is not a finding.

Fix: F-84677r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “BE9BA2D9-53EA-4CDC-84E5-9B1EEEE46550” and the Value to “1”.

b

Windows Defender AV must be configured block Office applications from creating child processes.

SC-18 - Medium - CCI-001170 - V-77967 - SV-92663r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000033

Vuln IDs

V-77967

Rule IDs

SV-92663r1_rule

Office apps, such as Word or Excel, will not be allowed to create child processes. This is a typical malware behavior, especially for macro-based attacks that attempt to use Office apps to launch or download malicious executables.

Checks: C-77577r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: D4F940AB-401B-4EFC-AADC-AD5F3C50688A Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “D4F940AB-401B-4EFC-AADC-AD5F3C50688A” is REG_SZ = 1, this is not a finding.

Fix: F-84679r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “D4F940AB-401B-4EFC-AADC-AD5F3C50688A” and the Value to “1”.

b

Windows Defender AV must be configured block Office applications from creating executable content.

SC-18 - Medium - CCI-001170 - V-77969 - SV-92665r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000034

Vuln IDs

V-77969

Rule IDs

SV-92665r1_rule

This rule targets typical behaviors used by suspicious and malicious add-ons and scripts (extensions) that create or launch executable files. This is a typical malware technique. Extensions will be blocked from being used by Office apps. Typically these extensions use the Windows Scripting Host (.wsh files) to run scripts that automate certain tasks or provide user-created add-on features.

Checks: C-77579r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: 3B576869-A4EC-4529-8536-B80A7769E899 Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “3B576869-A4EC-4529-8536-B80A7769E899” is REG_SZ = 1, this is not a finding.

Fix: F-84681r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “3B576869-A4EC-4529-8536-B80A7769E899” and the Value to “1”.

b

Windows Defender AV must be configured to block Office applications from injecting into other processes.

SC-18 - Medium - CCI-001170 - V-77971 - SV-92667r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000035

Vuln IDs

V-77971

Rule IDs

SV-92667r1_rule

Office apps, such as Word, Excel, or PowerPoint, will not be able to inject code into other processes. This is typically used by malware to run malicious code in an attempt to hide the activity from antivirus scanning engines.

Checks: C-77581r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: 75668C1F-73B5-4CF0-BB93-3ECF5CB7CC84 Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “75668C1F-73B5-4CF0-BB93-3ECF5CB7CC84” is REG_SZ = 1, this is not a finding.

Fix: F-84683r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “75668C1F-73B5-4CF0-BB93-3ECF5CB7CC84” and the Value to “1”.

b

Windows Defender AV must be configured to impede JavaScript and VBScript to launch executables.

SC-18 - Medium - CCI-001170 - V-77973 - SV-92669r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000036

Vuln IDs

V-77973

Rule IDs

SV-92669r1_rule

JavaScript and VBScript scripts can be used by malware to launch other malicious apps. This rule prevents these scripts from being allowed to launch apps, thus preventing malicious use of the scripts to spread malware and infect machines.

Checks: C-77583r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: D3E037E1-3EB8-44C8-A917-57927947596D Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “D3E037E1-3EB8-44C8-A917-57927947596D” is REG_SZ = 1, this is not a finding.

Fix: F-84685r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “D3E037E1-3EB8-44C8-A917-57927947596D” and the Value to “1”.

b

Windows Defender AV must be configured to block execution of potentially obfuscated scripts.

SC-18 - Medium - CCI-001170 - V-77975 - SV-92671r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000037

Vuln IDs

V-77975

Rule IDs

SV-92671r1_rule

Malware and other threats can attempt to obfuscate or hide their malicious code in some script files. This rule prevents scripts that appear to be obfuscated from running. It uses the AntiMalwareScanInterface (AMSI) to determine if a script is potentially obfuscated, and then blocks such a script, or blocks scripts when an attempt is made to access them.

Checks: C-77585r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: 5BEB7EFE-FD9A-4556-801D-275E5FFC04CC Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “5BEB7EFE-FD9A-4556-801D-275E5FFC04CC” is REG_SZ = 1, this is not a finding.

Fix: F-84687r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “5BEB7EFE-FD9A-4556-801D-275E5FFC04CC” and the Value to “1”.

b

Windows Defender AV must be configured to block Win32 imports from macro code in Office.

SC-18 - Medium - CCI-001170 - V-77977 - SV-92673r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000038

Vuln IDs

V-77977

Rule IDs

SV-92673r1_rule

This rule blocks potentially malicious behavior by not allowing macro code to execute routines in the Win 32 dynamic link library (DLL).

Checks: C-77587r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: 92E97FA1-2EDF-4476-BDD6-9DD0B4DDDC7B Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “92E97FA1-2EDF-4476-BDD6-9DD0B4DDDC7B” is REG_SZ = 1, this is not a finding.

Fix: F-84689r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “92E97FA1-2EDF-4476-BDD6-9DD0B4DDDC7B” and the Value to “1”.

b

Windows Defender AV must be configured to prevent user and apps from accessing dangerous websites.

SC-18 - Medium - CCI-001170 - V-77979 - SV-92675r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000039

Vuln IDs

V-77979

Rule IDs

SV-92675r1_rule

Enable Windows Defender Exploit Guard network protection to prevent employees from using any application to access dangerous domains that may host phishing scams exploit-hosting sites and other malicious content on the Internet.

Checks: C-77589r1_chk

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Network Protection -> "Prevent users and apps from accessing dangerous websites" is set to "Enabled” and “Block" selected in the drop down box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\Network Protection Criteria: If the value "EnableNetworkProtection" is REG_DWORD = 1, this is not a finding.

Fix: F-84691r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Network Protection -> "Prevent users and apps from accessing dangerous websites" to "Enabled” and select “Block" in the drop down box.

b

Windows Defender AV must be configured for automatic remediation action to be taken for threat alert level High.

SC-18 - Medium - CCI-001662 - V-79965 - SV-94669r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000040

Vuln IDs

V-79965

Rule IDs

SV-94669r1_rule

This policy setting allows you to customize which automatic remediation action will be taken for each threat alert level. Threat alert levels should be added under the Options for this setting. Each entry must be listed as a name value pair. The name defines a threat alert level. The value contains the action ID for the remediation action that should be taken. Valid threat alert levels are: 1 = Low 2 = Medium 4 = High 5 = Severe Valid remediation action values are: 2 = Quarantine 3 = Remove 6 = Ignore

Checks: C-79633r2_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" is set to "Enabled". Click the “Show…” box option and verify the ‘Value name’ field contains a value of “4” and the ‘Value’ field contains a “2". A value of “3” in the ‘Value’ field is more restrictive and also an acceptable value. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Threats\ThreatSeverityDefaultAction Criteria: If the value "4" is REG_SZ = 2 (or 3), this is not a finding.

Fix: F-86769r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" to "Enabled". Select the “Show…” option box and enter "4” in the ‘Value name’ field and enter “2" in the ‘Value’ field.

b

Windows Defender AV must be configured for automatic remediation action to be taken for threat alert level Medium.

SC-18 - Medium - CCI-001662 - V-79967 - SV-94671r1_rule

RMF Control

SC-18

Severity

M

CCI

Version

WNDF-AV-000041

Vuln IDs

V-79967

Rule IDs

SV-94671r1_rule

This policy setting allows you to customize which automatic remediation action will be taken for each threat alert level. Threat alert levels should be added under the Options for this setting. Each entry must be listed as a name value pair. The name defines a threat alert level. The value contains the action ID for the remediation action that should be taken. Valid threat alert levels are: 1 = Low 2 = Medium 4 = High 5 = Severe Valid remediation action values are: 2 = Quarantine 3 = Remove 6 = Ignore

Checks: C-79635r1_chk

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" is set to "Enabled". Click the “Show…” box option and verify the ‘Value name’ field contains a value of “2” and the ‘Value’ field contains a “2". A value of “3” in the ‘Value’ field is more restrictive and also an acceptable value. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Threats\ThreatSeverityDefaultAction Criteria: If the value "2" is REG_SZ = 2 (or 3), this is not a finding.

Fix: F-86771r1_fix

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" to "Enabled". Select the “Show…” option box and enter "2” in the ‘Value name’ field and enter “2" in the ‘Value’ field.

b

Windows Defender AV must be configured for automatic remediation action to be taken for threat alert level Low.

SC-18 - Medium - CCI-001662 - V-79971 - SV-94675r1_rule

RMF Control

SC-18

Severity

M

CCI