Windows 10: Security baseline (FINAL) for Windows 10 and Windows Server v1909 19H2

Brink · Nov 26, 2019

Microsoft is pleased to announce the final release of the security configuration baseline settings for Windows 10 version 1909 (a.k.a., “19H2”), and for Windows Server version 1909. Note that Windows Server version 1909 is Server Core only and does not offer a Desktop Experience (a.k.a., “full”) server installation option.

Download the content from the Microsoft Security Compliance Toolkit (click Download and select “Windows 10 Version 1909 and Windows Server Version 1909 Security Baseline.zip”).

This new Windows Feature Update brings very few new Group Policy settings, which we list in the accompanying documentation. None of them meet the criteria for inclusion in the baseline (which are reiterated below), but customers interested in controlling the use of USB drives and other devices should be interested in the new and very granular device installation restrictions. More about that later in this post.

The few changes we are making in the baseline since the September update to the version 1903 baselines are to remove a few settings that we have reevaluated: the restrictions on Thunderbolt devices in the BitLocker GPO, the enforcement of the default machine account password expiration for domain-joined systems, and the removal of the previously-recommended Exploit Protection settings.

Baseline criteria

To reiterate, we follow a streamlined and efficient approach to baseline definition when compared with the baselines we published before Windows 10. The foundation of that approach is essentially this:

The baselines are designed for well-managed, security-conscious organizations in which standard end users do not have administrative rights.

A baseline enforces a setting only if it mitigates a contemporary security threat and does not cause operational issues that are worse than the risks they mitigate.

A baseline enforces a default only if it is otherwise likely to be set to an insecure state by an authorized user:

If a non-administrator can set an insecure state, enforce the default.

If setting an insecure state requires administrative rights, enforce the default only if it is likely that a misinformed administrator will otherwise choose poorly.

For further illustration, see the “Why aren’t we enforcing more defaults?” section in this blog post.

Thunderbolt devices

First published in 2011, Microsoft Knowledge Base article 2516445 describes device installation restrictions for certain types of devices to mitigate DMA threats to BitLocker, including Thunderbolt devices. The BitLocker GPOs in our baselines have included these restrictions. Because Thunderbolt is popular, and newer computers can now mitigate that threat with kernel DMA protection – also in our baseline – we are removing the Thunderbolt restriction from our baseline. Customers on platforms that do not support kernel DMA protection can choose to continue blocking Thunderbolt, but we are no longer including it in our broad recommendations for all customers. For more information, see the KB article linked above and the articles to which it links.

Machine account password expiration

In Active Directory, each domain-joined computer has an Active Directory account with a strong, randomly-generated password. By default, these machine account passwords have a 30-day expiration, and computers automatically change their own passwords without any user involvement. Our baselines have always enforced these defaults. Note that reducing the expiration period will result in additional replication traffic. Also note that unlike with user account passwords, AD doesn’t actually enforce password expiration for computer accounts. Password expiration and change is driven entirely by client systems. The password remains valid until it gets changed, irrespective of how “Domain member: Maximum machine account password age” is configured.

A problem that occasionally crops up is that when a domain-joined virtual machine is reverted to an earlier state that is prior to its most recent password change, the older password is no longer recognized by the domain controller, the computer has no way to authenticate to the domain, and it thus loses domain trust. Domain accounts cannot authenticate to it remotely, and interactive logon with a domain account works only if the computer has a cached credential verifier for the account and the person logging in remembers which password was used when its verifier was cached. Typically when this happens, a LAPS-managed local account cannot be used either, as the local account password will also have been reverted and not match the newer one stored in Active Directory.

Non-persistent VDI implementations and devices with write filters that disallow permanent changes to the OS volume are also examples of scenarios where machine account password expiration is problematic. When such systems change their passwords in Active Directory and then revert to their previous passwords, they can no longer authenticate.

In the absence of issues such as these, we recommend leaving the default 30-day expiration in place. But following the baseline criteria stated above, we are removing the explicit enforcement of those defaults from our baselines. Situations that necessitate disabling machine account password expiration can now be handled without being out of compliance with our baselines.

The risks of turning off machine account password expiration are relatively low. To steal a computer account password, you must first have already gained full administrative control of the computer. Having a computer account’s password gives you only the ability to act as that computer on the network from other systems. For example, if Mary gets administrative control of CONTOSO\COMPUTER_ONE and extracts its domain account password (which is stored as an LSA secret), she can then connect to domain resources from CONTOSO\COMPUTER_TEN but pretending to be CONTOSO\COMPUTER_ONE. Default password expiration policy would limit her ability to do so to a maximum of 30 days. However, given that she had full control of COMPUTER_ONE, she could presumably go back in and retrieve its new password, or have applied nefarious techniques to disable password change, keeping the password valid indefinitely.

Exploit Protection

Because of reported compatibility issues with the Exploit Protection settings that we began incorporating with the Windows 10 v1709 baselines, we have elected to remove the settings from the baseline and to provide a script for removing the settings from machines that have had those settings applied. (See Remove-EPBaselineSettings.ps1 in the download package’s Scripts folder.)

New device installation restrictions available

For many years, Windows has enabled administrators to allow or block devices such as external USB drives based on attributes such as vendor and product IDs. Windows now also enables control at a far more granular level: device instance IDs. For example, you could have ten identical thumb drives of the same brand, model, and capacity, pick two of them, and create a policy that allows just those to be mounted; the others would be blocked.

Because the way these settings would be configured are always specific to each customer’s situation, we don’t configure them in our baselines. But we wanted to highlight their availability as a major improvement in Windows’ device control.

You can configure the new “Allow installation of devices that match any of these device instance IDs” and “Prevent installation of devices that match any of these device instance IDs” Group Policy settings in Computer Configuration\Administrative Templates\System\Device Installation\Device Installation Restrictions. For more information, also see How to control USB devices and other removable media using Microsoft Defender ATP.
Click to expand...

Source: https://techcommunity.microsoft.com/...r/ba-p/1023093

:)

Brink · Nov 26, 2019

Security baseline (FINAL) for Windows 10 and Windows Server v1909 19H2

Microsoft is pleased to announce the final release of the security configuration baseline settings for Windows 10 version 1909 (a.k.a., “19H2”), and for Windows Server version 1909. Note that Windows Server version 1909 is Server Core only and does not offer a Desktop Experience (a.k.a., “full”) server installation option.

Download the content from the Microsoft Security Compliance Toolkit (click Download and select “Windows 10 Version 1909 and Windows Server Version 1909 Security Baseline.zip”).

This new Windows Feature Update brings very few new Group Policy settings, which we list in the accompanying documentation. None of them meet the criteria for inclusion in the baseline (which are reiterated below), but customers interested in controlling the use of USB drives and other devices should be interested in the new and very granular device installation restrictions. More about that later in this post.

The few changes we are making in the baseline since the September update to the version 1903 baselines are to remove a few settings that we have reevaluated: the restrictions on Thunderbolt devices in the BitLocker GPO, the enforcement of the default machine account password expiration for domain-joined systems, and the removal of the previously-recommended Exploit Protection settings.

Baseline criteria

To reiterate, we follow a streamlined and efficient approach to baseline definition when compared with the baselines we published before Windows 10. The foundation of that approach is essentially this:

The baselines are designed for well-managed, security-conscious organizations in which standard end users do not have administrative rights.

A baseline enforces a setting only if it mitigates a contemporary security threat and does not cause operational issues that are worse than the risks they mitigate.

A baseline enforces a default only if it is otherwise likely to be set to an insecure state by an authorized user:

If a non-administrator can set an insecure state, enforce the default.

If setting an insecure state requires administrative rights, enforce the default only if it is likely that a misinformed administrator will otherwise choose poorly.

For further illustration, see the “Why aren’t we enforcing more defaults?” section in this blog post.

Thunderbolt devices

First published in 2011, Microsoft Knowledge Base article 2516445 describes device installation restrictions for certain types of devices to mitigate DMA threats to BitLocker, including Thunderbolt devices. The BitLocker GPOs in our baselines have included these restrictions. Because Thunderbolt is popular, and newer computers can now mitigate that threat with kernel DMA protection – also in our baseline – we are removing the Thunderbolt restriction from our baseline. Customers on platforms that do not support kernel DMA protection can choose to continue blocking Thunderbolt, but we are no longer including it in our broad recommendations for all customers. For more information, see the KB article linked above and the articles to which it links.

Machine account password expiration

In Active Directory, each domain-joined computer has an Active Directory account with a strong, randomly-generated password. By default, these machine account passwords have a 30-day expiration, and computers automatically change their own passwords without any user involvement. Our baselines have always enforced these defaults. Note that reducing the expiration period will result in additional replication traffic. Also note that unlike with user account passwords, AD doesn’t actually enforce password expiration for computer accounts. Password expiration and change is driven entirely by client systems. The password remains valid until it gets changed, irrespective of how “Domain member: Maximum machine account password age” is configured.

A problem that occasionally crops up is that when a domain-joined virtual machine is reverted to an earlier state that is prior to its most recent password change, the older password is no longer recognized by the domain controller, the computer has no way to authenticate to the domain, and it thus loses domain trust. Domain accounts cannot authenticate to it remotely, and interactive logon with a domain account works only if the computer has a cached credential verifier for the account and the person logging in remembers which password was used when its verifier was cached. Typically when this happens, a LAPS-managed local account cannot be used either, as the local account password will also have been reverted and not match the newer one stored in Active Directory.

Non-persistent VDI implementations and devices with write filters that disallow permanent changes to the OS volume are also examples of scenarios where machine account password expiration is problematic. When such systems change their passwords in Active Directory and then revert to their previous passwords, they can no longer authenticate.

In the absence of issues such as these, we recommend leaving the default 30-day expiration in place. But following the baseline criteria stated above, we are removing the explicit enforcement of those defaults from our baselines. Situations that necessitate disabling machine account password expiration can now be handled without being out of compliance with our baselines.

The risks of turning off machine account password expiration are relatively low. To steal a computer account password, you must first have already gained full administrative control of the computer. Having a computer account’s password gives you only the ability to act as that computer on the network from other systems. For example, if Mary gets administrative control of CONTOSO\COMPUTER_ONE and extracts its domain account password (which is stored as an LSA secret), she can then connect to domain resources from CONTOSO\COMPUTER_TEN but pretending to be CONTOSO\COMPUTER_ONE. Default password expiration policy would limit her ability to do so to a maximum of 30 days. However, given that she had full control of COMPUTER_ONE, she could presumably go back in and retrieve its new password, or have applied nefarious techniques to disable password change, keeping the password valid indefinitely.

Exploit Protection

Because of reported compatibility issues with the Exploit Protection settings that we began incorporating with the Windows 10 v1709 baselines, we have elected to remove the settings from the baseline and to provide a script for removing the settings from machines that have had those settings applied. (See Remove-EPBaselineSettings.ps1 in the download package’s Scripts folder.)

New device installation restrictions available

For many years, Windows has enabled administrators to allow or block devices such as external USB drives based on attributes such as vendor and product IDs. Windows now also enables control at a far more granular level: device instance IDs. For example, you could have ten identical thumb drives of the same brand, model, and capacity, pick two of them, and create a policy that allows just those to be mounted; the others would be blocked.

Because the way these settings would be configured are always specific to each customer’s situation, we don’t configure them in our baselines. But we wanted to highlight their availability as a major improvement in Windows’ device control.

You can configure the new “Allow installation of devices that match any of these device instance IDs” and “Prevent installation of devices that match any of these device instance IDs” Group Policy settings in Computer Configuration\Administrative Templates\System\Device Installation\Device Installation Restrictions. For more information, also see How to control USB devices and other removable media using Microsoft Defender ATP.
Click to expand...

Source: https://techcommunity.microsoft.com/...r/ba-p/1023093

Brink · Nov 26, 2019

Security baseline (DRAFT) for Windows 10 v1809 and Windows Server 2019

Microsoft is pleased to announce the draft release of the security configuration baseline settings for Windows 10 version 1809 (a.k.a., “Redstone 5” or “RS5”), and for Windows Server 2019. Please evaluate these proposed baselines and send us your feedback via blog comments below.

Download the content here: Windows-10-1809-Security-Baseline-DRAFT.zip

The downloadable attachment to this blog post includes importable GPOs, a PowerShell script for applying the GPOs to local policy, custom ADMX files for Group Policy settings, documentation in spreadsheet form and as a Policy Analyzer file (MSFT-Win10-v1809-RS5-WS2019-DRAFT.PolicyRules). In this release, we have changed the documentation layout in a few ways:

MS Security Baseline Windows 10 v1809 and Server 2019.xlsx – multi-tabbed workbook listing all Group Policy settings that ship in-box with Windows 10 v1809 or Windows Server 2019. Columns for “Windows 10 v1809,” “WS2019 Member Server,” and “WS2019 DC” show the recommended settings for those three scenarios. A small number of cells are color-coded to indicate that the settings should not be applied to systems that are not joined to an Active Directory domain. Cells in the “WS2019 DC” columns are also highlighted when they differ from the corresponding cells in the “WS2019 Member Server” column. Another change from past spreadsheets is that we have combined tabs that used to be separate. Specifically, we are no longer breaking out Internet Explorer and Windows Defender AV settings into separate tabs, nor the settings for LAPS, MS Security Guide, and MSS (Legacy). All these settings are now in the Computer and User tabs.

BaselineDiffs-to-v1809-RS5-DRAFT.xlsx – This Policy Analyzer-generated workbook lists the differences in Microsoft security configuration baselines between the new baselines and the corresponding previous baselines. The Windows 10 v1809 settings are compared against those for Windows 10 v1803, and the Windows Server 2019 baselines are compared against those for Windows Server 2016.

Windows 10 1803 to 1809 New Settings.xlsx – Lists all the settings that are available in Windows 10 v1809 that were added since Windows 10 v1803. (We used to highlight these settings in the big all-settings spreadsheets.)

Server 2016 to 2019 New Settings.xlsx – Lists all the settings that are available in Windows Server 2019 that were added since Windows Server 2016. (We used to highlight these settings in the big all-settings spreadsheets.)

Highlights of the differences from past baselines, which are listed in BaselineDiffs-to-v1809-RS5-DRAFT.xlsx:

The MS Security Guide custom setting protecting against potentially unwanted applications (PUA) has been deprecated, and is now implemented with a new setting under Computer Configuration\...\Windows Defender Antivirus.

We have enabled the “Encryption Oracle Remediation” setting we had considered for v1803. At the time we were concerned that enabling the newly-introduced setting would break too many not-yet-patched systems. We assume that systems have since been brought up to date. (You can read information about the setting here and here.)

Changes to Virtualization-Based Security settings (used by Credential Guard and Code Integrity):

“Platform Security Level” changed from “Secure Boot and DMA Protection” to “Secure Boot.” If system hardware doesn’t support DMA protection, selecting “Secure Boot and DMA Protection” prevents Credential Guard from operating. If you can affirm that your systems support the DMA protection feature, choose the stronger option. We have opted for “Secure Boot” (only) in the baseline to reduce the likelihood that Credential Guard fails to run.

Enabled the new System Guard Secure Launch setting which will enable Secure Launch on new capable hardware. Secure Launch changes the way windows boots to use Intel Trusted Execution Technology (TXT) and Runtime BIOS Resilience features to prevent firmware exploits from being able to impact the security of the Windows Virtualization Based Security environment.

Enabled the “Require UEFI Memory Attributes Table” option.

Enabled the new Kernel DMA Protection feature described here. The “External device enumeration” policy controls whether to enumerate external devices that are not compatible with DMA-remapping. Devices that are compatible with DMA-remapping are always enumerated.

Removed the BitLocker setting, “Allow Secure Boot for integrity validation,” as it merely enforced a default that was unlikely to be modified even by a misguided administrator.

Removed the BitLocker setting, “Configure minimum PIN length for startup,” as new hardware features reduce the need for a startup PIN, and the setting increased Windows’ minimum by only one character.

Enabled the new Microsoft Edge setting to prevent users from bypassing certificate error messages, bringing Edge in line with a similar setting for Internet Explorer.

Removed the block against handling PKU2U authentication requests, as the feature is increasingly necessary.

Removed the configuration of the “Create symbolic links” user rights assignment, as it merely enforced a default, was unlikely to be modified by a misguided administrator or for malicious purposes, and needs to be changed to a different value when Hyper-V is enabled.

Removed the deny-logon restrictions against the Guests group as unnecessary: by default, the Guest account is the only member of the Guests group, and the Guest account is disabled. Only an administrator can enable the Guest account or add members to the Guests group.

Removed the disabling of the xbgm (“Xbox Game Monitoring”) service, as it is not present in Windows 10 v1809. (By the way, consumer services such as the Xbox services have been removed from Windows Server 2019 with Desktop Experience!)

Removed Credential Guard from the Domain Controller baseline. (Credential Guard is not useful on domain controllers and is not supported there.)

Created and enabled a new custom MS Security Guide setting for the domain controller baseline, “Extended Protection for LDAP Authentication (Domain Controllers only),” which configures the LdapEnforceChannelBinding registry value described here.

The Server 2019 baselines pick up all the changes accumulated in the four Windows 10 releases since Windows Server 2016.

We have replaced the collection of .cmd batch files for applying the baselines to local policy with a single PowerShell script that takes one of these five command-line switches to indicate which baseline you want to apply:.\BaselineLocalInstall.ps1 -Win10DomainJoined - for Windows 10 v1809, domain-joined
.\BaselineLocalInstall.ps1 -Win10NonDomainJoined - for Windows 10 v1809, non-domain-joined
.\BaselineLocalInstall.ps1 -WS2019Member - for Windows Server 2019, domain-joined
.\BaselineLocalInstall.ps1 -WS2019NonDomainJoined - for Windows Server 2019, non-domain-joined
.\BaselineLocalInstall.ps1 -WS2019DomainController - for Windows Server 2019, domain controller
A couple of important notes about using the BaselineLocalInstall.ps1 script:

PowerShell execution policy must be configured to allow script execution. You can configure this with a command line such as the following:
Set-ExecutionPolicy RemoteSigned

LGPO.exe must be in the Tools subdirectory or somewhere in the Path. LGPO.exe is part of the Security Compliance Toolkit and can be downloaded from this URL:
https://www.microsoft.com/download/d....aspx?id=55319

Windows 10 v1809 has greatly expanded its manageability using Mobile Device Management (MDM). The Intune team is preparing documentation about the Microsoft Windows MDM security baseline and how to use Intune to implement the baseline, and will publish it very soon. We will post information to this blog when that happens.
Click to expand...

Source: Security baseline (DRAFT) for Windows 10 v1809 and Windows Server 2019 Microsoft Security Guidance blog

Download: Windows-10-1809-Security-Baseline-DRAFT.zip

Brink · Nov 26, 2019

Security baseline (FINAL) for Windows 10 v1903 & Windows Server v1903

Microsoft is pleased to announce the final release of the security configuration baseline settings for Windows 10 version 1903 (a.k.a., “19H1”), and for Windows Server version 1903.

Download the content from the Microsoft Security Compliance Toolkit (click Download and select Windows 10 Version 1903 and Windows Server Version 1903 Security Baseline.zip).

Note that Windows Server version 1903 is Server Core only and does not offer a Desktop Experience (a.k.a., “full”) server installation option. In the past we have published baselines only for “full” server releases – Windows Server 2016 and 2019. Beginning with this release we intend to publish baselines for Core-only Windows Server versions as well. However, we do not intend at this time to distinguish settings in the baseline that apply only to Desktop Experience. When applied to Server Core, those settings are inert for all intents and purposes.

This new Windows Feature Update brings very few new Group Policy settings, which we list in the accompanying documentation. This baseline recommends configuring only two of those. However, we have made several changes to existing settings, including some changes since the draft version of this baseline that we published last month.

The changes from the Windows 10 v1809 and Windows Server 2019 baselines include:

Enabling the new “Enable svchost.exe mitigation options” policy, which enforces stricter security on Windows services hosted in svchost.exe, including that all binaries loaded by svchost.exe must be signed by Microsoft, and that dynamically-generated code is disallowed. Please pay special attention to this one as it might cause compatibility problems with third-party code that tries to use the svchost.exe hosting process, including third-party smart-card plugins.

Configuring the new App Privacy setting, “Let Windows apps activate with voice while the system is locked,” so that users cannot interact with applications using speech while the system is locked.

Disabling multicast name resolution (LLMNR) to mitigate server spoofing threats.

Restricting the NetBT NodeType to P-node, disallowing the use of broadcast to register or resolve names, also to mitigate server spoofing threats. We have added a setting to the custom “MS Security Guide” ADMX to enable managing this configuration setting through Group Policy.

Correcting an oversight in the Domain Controller baseline by adding recommended auditing settings for Kerberos authentication service.

Dropping the password-expiration policies that require periodic password changes. This change is discussed in further detail below.

Dropping the specific BitLocker drive encryption method and cipher strength settings. The baseline has been requiring the strongest available BitLocker encryption. We are removing that item for a few reasons. The default is 128-bit encryption, and our crypto experts tell us that there is no known danger of its being broken in the foreseeable future. On some hardware there can be noticeable performance degradation going from 128- to 256-bit. And finally, many devices such as those in the Microsoft Surface line turn on BitLocker by default and use the default algorithms. Converting those to use 256-bit requires first decrypting the volumes and then re-encrypting, which creates temporary security exposure as well as user impact.

Dropping the File Explorer “Turn off Data Execution Prevention for Explorer” and “Turn off heap termination on corruption” settings, as it turns out they merely enforce default behavior, as Raymond Chen describes here.

Additional changes that we have adopted since publishing the draft version of this baseline include:

Dropping the enforcement of the default behavior of disabling the built-in Administrator and Guest accounts. We had floated this proposal at the time of the draft baseline, and have since decided to accept it. The change is discussed in more detail below.

Dropped a Windows Defender Antivirus setting that applies only to legacy email file formats.

Changed the Windows Defender Exploit Protection XML configuration to allow Groove.exe (OneDrive for Business) to launch child processes, particularly MsoSync.exe which is necessary for file synchronization.

Dropping the password expiration policies.

There’s no question that the state of password security is problematic and has been for a long time. When humans pick their own passwords, too often they are easy to guess or predict. When humans are assigned or forced to create passwords that are hard to remember, too often they’ll write them down where others can see them. When humans are forced to change their passwords, too often they’ll make a small and predictable alteration to their existing passwords, and/or forget their new passwords. When passwords or their corresponding hashes are stolen, it can be difficult at best to detect or restrict their unauthorized use.

Recent scientific research calls into question the value of many long-standing password-security practices such as password expiration policies, and points instead to better alternatives such as enforcing banned-password lists (a great example being Azure AD password protection) and multi-factor authentication. While we recommend these alternatives, they cannot be expressed or enforced with our recommended security configuration baselines, which are built on Windows’ built-in Group Policy settings and cannot include customer-specific values.

This reinforces a larger important point about our baselines: while they are a solid foundation and should be part of your security strategy, they are not a complete security strategy. In this particular case, the small set of ancient password policies enforceable through Windows’ security templates is not and cannot be a complete security strategy for user credential management. Removing a low-value setting from our baseline and not compensating with something else in the baseline does not mean we are lowering security standards. It simply reinforces that security cannot be achieved entirely with baselines.

Why are we removing password-expiration policies?

First, to try to avoid inevitable misunderstandings, we are talking here only about removing password-expiration policies – we are not proposing changing requirements for minimum password length, history, or complexity.
Periodic password expiration is a defense only against the probability that a password (or hash) will be stolen during its validity interval and will be used by an unauthorized entity. If a password is never stolen, there’s no need to expire it. And if you have evidence that a password has been stolen, you would presumably act immediately rather than wait for expiration to fix the problem.

If it’s a given that a password is likely to be stolen, how many days is an acceptable length of time to continue to allow the thief to use that stolen password? The Windows default is 42 days. Doesn’t that seem like a ridiculously long time? Well, it is, and yet our current baseline says 60 days – and used to say 90 days – because forcing frequent expiration introduces its own problems. And if it’s not a given that passwords will be stolen, you acquire those problems for no benefit. Further, if your users are the kind who are willing to answer surveys in the parking lot that exchange a candy bar for their passwords, no password expiration policy will help you.

Our baselines are intended to be usable with minimal if any modification by most well-managed, security-conscious enterprises. They are also intended to serve as guidance for auditors. So, what should the recommended expiration period be? If an organization has successfully implemented banned-password lists, multi-factor authentication, detection of password-guessing attacks, and detection of anomalous logon attempts, do they need any periodic password expiration? And if they haven’t implemented modern mitigations, how much protection will they really gain from password expiration?

The results of baseline compliance scans are usually measured by how many settings are out of compliance: “How much red do we have on the chart?” It is not unusual for organizations during audit to treat compliance numbers as more important than real-world security. If a baseline recommends 60 days and an organization with advanced protections opts for 365 days – or no expiration at all – they will get dinged in an audit unnecessarily and might be compelled to adhere to the 60-day recommendation.

Periodic password expiration is an ancient and obsolete mitigation of very low value, and we don’t believe it’s worthwhile for our baseline to enforce any specific value. By removing it from our baseline rather than recommending a particular value or no expiration, organizations can choose whatever best suits their perceived needs without contradicting our guidance. At the same time, we must reiterate that we strongly recommend additional protections even though they cannot be expressed in our baselines.

Dropping the enforced disabling of the built-in Administrator and Guest accounts

To keep baselines useful and manageable, we tend to enforce secure defaults for policy settings only when 1) non-administrative users could otherwise override those defaults, or 2) misinformed administrators are otherwise likely to make poor choices about the setting. Neither of those conditions are true regarding enforcing the default disabling of the Administrator and Guest accounts. Note that removing these settings from the baseline does not mean that we recommend that these accounts be enabled, nor does removing these settings mean that the accounts will be enabled. Removing the settings from the baselines simply means that administrators can now choose to enable these accounts as needed.

The built-in Guest account. The Guest account (RID -501) is disabled by default on Windows 10 and Windows Server. Only an administrator can enable the Guest account, and an admin would presumably do so only for a valid reason such as for a kiosk system.

The built-in Administrator account. The local Administrator account (RID -500) is disabled by default on Windows 10 but not on Windows Server. When installing Windows 10, Windows Setup prompts you for a new account which becomes the primary administrative account for the computer. By contrast, Windows Server’s setup prompts you for a new password for the Administrator account. The main differences between the built-in -500 Administrator account (when enabled) and a custom administrative local account are 1) the -500 account is not subject to account lockout, account expiration, password expiration, or logon hours; 2) the -500 account cannot be removed from the Administrators group; and 3) that by default the -500 account always runs with full administrative rights without UAC prompts, including over the network. This third difference can be removed (as our baselines always do) by enabling the security option, “User Account Control: Admin Approval Mode for the Built-in Administrator account.”

Our recommendations for administrative local accounts include:

You can choose not to have any administrative local accounts enabled and to administer domain-joined systems only with domain accounts.

If you choose to use local accounts for computer administration, you should have only one administrative local account enabled per computer. With this change in the baseline, you can choose to use the -500 Administrator account or a custom account, according to your needs. Note that if you rely on account lockout for defense against password-guessing attacks, you should not enable the -500 account – and you should consider disabling it on Windows Server.

The administrative local account’s password should be strong and should be different from the same account’s password on every other computer. We recommend the Local Administrator Password Solution (LAPS) or a similar tool to ensure that passwords are random and strong. LAPS can manage the password of the -500 account or a custom named local account on Active Directory domain-joined Windows clients and domain-joined member servers (but not for Domain Controllers). Note also that LAPS’ password-expiration enforcement is independent from Windows’ password-expiration mechanism, and always applies to whatever account LAPS manages.

Renaming the Administrator account is perfectly fine but is “security by obscurity.” Renaming is easy to do through Group Policy and doing so can mitigate some threats, but it’s less than a speedbump against other threats.

Click to expand...

Source: https://blogs.technet.microsoft.com/...-server-v1903/

Windows 10: Security baseline (FINAL) for Windows 10 and Windows Server v1909 19H2

Security baseline (FINAL) for Windows 10 and Windows Server v1909 19H2

Security baseline (FINAL) for Windows 10 and Windows Server v1909 19H2

Security baseline (FINAL) for Windows 10 and Windows Server v1909 19H2

Security baseline (FINAL) for Windows 10 and Windows Server v1909 19H2 - Similar Threads - Security baseline FINAL

Security baseline FINAL for Windows 10 version 21H1

Security baseline (FINAL) Windows 10 and Windows Server version 20H2

Security baseline (DRAFT): Windows 10 and Windows Server version 20H2

Security baseline (FINAL): Windows 10 and Windows Server, version 2004

Security baseline (DRAFT) for Windows 10 and Windows Server v2004

[sandbox] loss of connectivity after deployment of Security baseline (FINAL) for Windows 10...

Security baseline (FINAL) for Windows 10 v1903 & Windows Server v1903

Security baseline DRAFT for Windows 10 and Windows Server 2019 v1903

Security baseline (DRAFT) for Windows 10 v1809 and Windows Server 2019

Users found this page by searching for:

msft-win10-v1909-final.policyrules