Updating List of Trusted Root Certificates in Windows

All Windows versions have a built-in feature for automatically updating root certificates from the Microsoft websites. MSFT, as part of the Microsoft Trusted Root Certificate Program, maintains and publishes a list of trusted certificates for clients and Windows devices in its online repository. If the verified certificate in its certification chain refers to the root CA that participates in this program, the system will automatically download this root certificate from the Windows Update servers and add it to the trusted ones.

In this article, we’ll try to find out how to manually update the list of root certificates in TrustedRootCA in disconnected (isolated) networks or computers/servers without direct Internet access.

Managing Trusted Root Certificates in Windows 10 and 11

How to see the list of trusted root certificates on a Windows computer?

1. To open the root certificate store of a computer running Windows 11/10/8.1/7 or Windows Server 2022/2019/2016, run the mmc.exe console;
2. Select File -> Add/Remove Snap-in, select Certificates (certmgr) in the list of snap-ins -> Add;
3. Select that you want to manage certificates of local Computer account;
4. Next -> OK -> OK;
5. Expand the Certificates node -> Trusted Root Certification Authorities Store. This section contains the list of trusted root certificates on your computer.

In the mmc console, you can view information about any certificate or remove it from trusted ones.

You can also get a list of trusted root certificates with their expiration dates using PowerShell:

Get-Childitem cert:\LocalMachine\root |format-list

You can list the expired certificates, or which expire in the next 60 days:

Get-ChildItem cert:\LocalMachine\root|Where {$_.NotAfter -lt  (Get-Date).AddDays(60)}|select NotAfter, Subject

You can manually transfer the root certificate file between Windows computers using the Export/Import options.

1. You can export any certificate to a .CER file by clicking on it and selecting All Tasks -> Export;
2. You can import this certificate on another computer using the option All Tasks -> Import.

How to Disable/Enable Automatic Root Certificates Update in Windows?

As we mentioned, Windows automatically updates root certificates. You can enable or disable certificate renewal in Windows through a GPO or the registry.

Open the Local Group Policy Editor (gpedit.msc) and go to Computer Configuration -> Administrative Templates -> System -> Internet Communication Management -> Internet Communication.

The Turn off Automatic Root Certificates Update option in this section allows you to disable automatic updating of root certificates through the Windows Update sites. By default, this policy is not configured and Windows always tries to automatically renew root certificates.

If this GPO option is not configured and the root certificates are not automatically renewed, check if this setting is manually enabled in the registry. Check the value of the registry parameter using PowerShell:

Get-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\SystemCertificates\AuthRoot' -Name DisableRootAutoUpdate

If the command returns that the value of the DisableRootAutoUpdate registry parameter is 1, then the updating of root certificates is disabled on your computer. To enable it, change the parameter value to 0.

Certutil: Download Trusted Root Certificates from Windows Update

Certutil.exe CLI tool can be used to manage certificates (introduced in Windows 10, for Windows 7 is available as a separate update). It can be used to download an up-to-date list of root certificates from Windows Update and save it to an SST file.

To generate an SST file on a computer running Windows 10 or 11 and having direct access to the Internet, open the elevated command prompt and run the command:

certutil.exe -generateSSTFromWU C:\PS\roots.sst

Updated SST file.
CertUtil: -generateSSTFromWU command completed successfully.

As a result, an SST file containing an up-to-date list of root certificates will appear in the target directory. Double-click to open it. This file is a container containing trusted root certificates.

As you can see, a familiar Certificate Management snap-in opens, from which you can export any of the certificates you have got. In my case, there have been 358 items in the list of certificates. Obviously, it is not rational to export the certificates and install them one by one.

You can use PowerShell script to install all certificates from the SST file and add them to the list of trusted root certificates on a computer:

$sstStore = ( Get-ChildItem -Path C:\ps\rootsupd\roots.sst )
$sstStore | Import-Certificate -CertStoreLocation Cert:\LocalMachine\Root

Run the certmgr.msc snap-in and make sure that all certificates have been added to the Trusted Root Certification Authority. In my example on Windows 11, the number of root certificates increased from 34 to 438.

Certificate Trust List (STL) in Windows

A Certificate Trust List (CTL) is simply a list of data (such as certificate hashes) that is signed by a trusted party (by Microsoft in this case). The Windows client periodically downloads from Windows Update this CTL, which stores the hashes of all trusted root CAs.  It should be understood that this CTL doesn’t contain the certificates themselves, only their hashes and attributes (for example, Friendly Name). Windows devices can download a trusted certificate from Certificate Trust List on demand.

You can manually download and install the CTL file. To do it, download the file http://ctldl.windowsupdate.com/msdownload/update/v3/static/trustedr/en/authrootstl.cab (updated twice a month). Using any archiver (or even Windows Explorer), unpack the contents of the authrootstl.cab archive. It contains a single authroot.stl file.

The Authroot.stl file is a container with a list of trusted certificate thumbprints in Certificate Trust List format.

You can install this CTL file to a Trusted Root Certificate Authority using the certutil command:

certutil -enterprise -f -v -AddStore "Root" "C:\PS\authroot.stl"

root "Trusted Root Certification Authorities"
CTL 0 added to store.
CertUtil: -addstore command completed successfully.

You can also import certificates using the certificate management console (Trust Root Certification Authorities -> Certificates -> All Tasks -> Import). Specify the path to your STL file with certificate thumbprints.

After you have run the command, a new section Certificate Trust List appears in Trusted Root Certification Authorities container of the Certificate Manager console (certmgr.msc).

In the same way, you can download and install the list of the revoked (disallowed) certificates that have been removed from the Root Certificate Program. To do it, download the disallowedcertstl.cab file (http://ctldl.windowsupdate.com/msdownload/update/v3/static/trustedr/en/disallowedcertstl.cab), extract it, and add it to the Untrusted Certificates store with the command:

certutil -enterprise -f -v -AddStore disallowed "C:\PS\disallowedcert.stl"

Updating Trusted Root Certificates via GPO in an Isolated Environment

If you have the task of regularly updating root certificates in an Internet-isolated Active Directory domain, there is a slightly more complicated scheme for updating local certificate stores on domain-joined computers using Group Policies. You can configure root certificate updates on user computers in the disconnected Windows networks in several ways.

The first way assumes that you regularly manually download and copy a file with root certificates to your isolated network. You can download the file with current Microsoft root certificates as follows:

certutil.exe –generateSSTFromWU roots.sst

Then the root certificates from this file can be deployed via SCCM or PowerShell Startup script in GPO:

$sstStore = (Get-ChildItem -Path \\fr-dc01\SYSVOL\woshub.com\rootcert\roots.sst )
$sstStore | Import-Certificate -CertStoreLocation Cert:\LocalMachine\Root

The second way is to download the actual Microsoft root certificates using the command:

Certutil -syncWithWU -f \\fr-dc01\SYSVOL\woshub.com\rootcert\

A number of root certificate files (CRT file format) will appear in the specified shared network folder (including files authrootstl.cab, disallowedcertstl.cab, disallowedcert.sst, thumbprint.crt).

Then use the Group Policy Preferences to change the value of the registry parameter RootDirURL under HKLM\Software\Microsoft\SystemCertificates\AuthRoot\AutoUpdate. This parameter should point to the shared network folder from which your Windows computers will receive new root certificates. Run the domain GPMC.msc console, create a new GPO, switch to the edit policy mode, and expand the section Computer Configuration -> Preferences -> Windows Settings -> Registry. Create a new registry property with the following settings:

• Action: Update
• Hive: HKLM
• Key path: Software\Microsoft\SystemCertificates\AuthRoot\AutoUpdate
• Value name: RootDirURL
• Type: REG_SZ
• Value data: file://\\fr-dc01\SYSVOL\woshub.com\rootcert\

It remains to link this policy on a computer`s OU and after updating GPO settings on the client, check for new root certificates in the certstore.

How to Update Trusted Root Certificates in Windows 7?

Despite the fact that Windows 7 is now is at the End of Support phase, many users and companies still use it.

After installing a clean Windows 7 image, you may find that many modern programs and tools do not work on it as they are signed with new certificates. In particular, there have been complaints that .Net Framework 4.8 or Microsoft Visual Studio (vs_Community.exe) cannot be installed on Windows 7 SP1 x64 without updating root certificates.

The installer manifest failed signature validation.

Or

NET Framework has not been installed because a certificate chain could not be built to a trusted root authority.

To update root certificates in Windows 7, you must first download and install MSU update KB2813430 (https://support.microsoft.com/en-us/topic/an-update-is-available-that-enables-administrators-to-update-trusted-and-disallowed-ctls-in-disconnected-environments-in-windows-0c51c702-fdcc-f6be-7089-4585fad729d6)

After that, you can use the certutil to generate an SST file with root certificates (on current or another computer):

certutil.exe -generateSSTFromWU c:\ps\roots.sst

Now you can import certificates into trusted ones:

Run MMC -> add snap-in -> certificates -> computer account > local computer. Right click Trusted root certification authority, All Tasks -> Import, find your SST file (in the file type select Microsoft Serialized Certificate Store — *.sst) -> Open -> Place all certificates in the following store -> Trusted Root Certification Authorities.

Updating Root Certificates on Windows XP Using the Rootsupd.exe Tool

In Windows XP, the rootsupd.exe utility was used to update the computer`s root certificates. The list of root and revoked certificates in it was regularly updated. The tool was distributed as a separate update KB931125 (Update for Root Certificates). Let’s see if we can use it now.

1. Download the rootsupd.exe utility using the following link http://download.windowsupdate.com/msdownload/update/v3/static/trustedr/en/rootsupd.exe. At the moment (January 2021) the link doesn’t work, Microsoft decided to remove it from the public. Today you can download the rootsupd.exe from the Kaspersky website — http://media.kaspersky.com/utilities/CorporateUtilities/rootsupd.zip;
2. To install the Windows root certificates, just run the rootsupd.exe file. But we will try to examine its contents more carefully. Extract the certificates from the executable file with the command: rootsupd.exe /c /t: C:\PS\rootsupd
3. Certificates are stored in SST files, like authroots.sst, delroot.sst, etc. To remove or install certificates, you can use the following commands:
   updroots.exe authroots.sst
updroots.exe -d delroots.sst

However, as you can see, these certificate files were created on April 4, 2013 (almost a year before the end of official support for Windows XP). Thus, since then the tool has not been updated and cannot be used to install up-to-date certificates.

But you can use cerutil tool in Windows 10/11 to download root.sst, copy that file in Windows XP and install the certificate using updroots.exe:

updroots.exe c:\temp\roots.sst

In this article, we looked at several ways to update trusted root certificates on Windows network computers that are isolated from the Internet (disconnected environment).