Windows Server 2019 Exploit Protection system-level mitigation, Randomize memory allocations (Bottom-Up ASLR), must be on.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-205831	WN19-EP-000020	SV-205831r569188_rule		Medium

Description
Exploit protection enables mitigations against potential threats at the system and application level. Several mitigations, including "Randomize memory allocations (Bottom-Up ASLR)", are enabled by default at the system level. Bottom-Up ASLR (address space layout randomization) randomizes locations for virtual memory allocations, including those for system structures. If this is turned off, Windows may be subject to various exploits.

Description

Exploit protection enables mitigations against potential threats at the system and application level. Several mitigations, including "Randomize memory allocations (Bottom-Up ASLR)", are enabled by default at the system level. Bottom-Up ASLR (address space layout randomization) randomizes locations for virtual memory allocations, including those for system structures. If this is turned off, Windows may be subject to various exploits.

STIG	Date
Microsoft Windows Server 2019 Security Technical Implementation Guide	2020-10-26

Details

Check Text ( C-6096r355855_chk )
This is applicable to unclassified systems, for other systems this is NA. The default configuration in Exploit Protection is "On by default" which meets this requirement. The PowerShell query results for this show as "NOTSET". Run "Windows PowerShell" with elevated privileges (run as administrator). Enter "Get-ProcessMitigation -System". If the status of "ASLR: BottomUp" is "OFF", this is a finding. Values that would not be a finding include: ON NOTSET (Default configuration)

Check Text ( C-6096r355855_chk )

This is applicable to unclassified systems, for other systems this is NA.

The default configuration in Exploit Protection is "On by default" which meets this requirement. The PowerShell query results for this show as "NOTSET".

Run "Windows PowerShell" with elevated privileges (run as administrator).

Enter "Get-ProcessMitigation -System".

If the status of "ASLR: BottomUp" is "OFF", this is a finding.

Values that would not be a finding include:

ON
NOTSET (Default configuration)

Fix Text (F-6096r355856_fix)
Ensure Exploit Protection system-level mitigation, "Randomize memory allocations (Bottom-Up ASLR)" is turned on. The default configuration in Exploit Protection is "On by default" which meets this requirement. Open "Windows Defender Security Center". Select "App & browser control". Select "Exploit protection settings". Under "System settings", configure "Randomize memory allocations (Bottom-Up ASLR)" to "On by default" or "Use default ()". The STIG package includes a DoD EP XML file in the "Supporting Files" folder for configuring application mitigations defined in the STIG. This can also be modified to explicitly enforce the system level requirements. Adding the following to the XML file will explicitly turn Bottom-Up ASLR on (other system level EP requirements can be combined under ): The XML file is applied with the group policy setting Computer Configuration >> Administrative Settings >> Windows Components >> Windows Defender Exploit Guard >> Exploit Protection >> "Use a common set of exploit protection settings" configured to "Enabled" with file name and location defined under "Options:". It is recommended the file be in a read-only network location.

Fix Text (F-6096r355856_fix)

Ensure Exploit Protection system-level mitigation, "Randomize memory allocations (Bottom-Up ASLR)" is turned on. The default configuration in Exploit Protection is "On by default" which meets this requirement.

Open "Windows Defender Security Center".

Select "App & browser control".

Select "Exploit protection settings".

Under "System settings", configure "Randomize memory allocations (Bottom-Up ASLR)" to "On by default" or "Use default ()".

The STIG package includes a DoD EP XML file in the "Supporting Files" folder for configuring application mitigations defined in the STIG. This can also be modified to explicitly enforce the system level requirements. Adding the following to the XML file will explicitly turn Bottom-Up ASLR on (other system level EP requirements can be combined under ):

The XML file is applied with the group policy setting Computer Configuration >> Administrative Settings >> Windows Components >> Windows Defender Exploit Guard >> Exploit Protection >> "Use a common set of exploit protection settings" configured to "Enabled" with file name and location defined under "Options:". It is recommended the file be in a read-only network location.