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Decommissioning an Old Certification Authority without affecting Previously Issued Certificates and then Switching Operations to a New One

  • Artigo

Jonathan Stephens posted an excellent Blog about this topic; however, it didn’t include the steps. As a result, I decided to type this Blog detailing the steps required. The following assumptions have to be met before proceeding with these steps:

1- There is a new valid Certification Authority configured

2- There is a new distribution point configured for AIA and CDP locations named https://crl.contoso.com/CertData

Steps:

1- Logon to the old Enterprise Certification Authority as an Enterprise Administrator.

2- Identify the AIA and CDP distribution points

  1. a. Open the Certification Authority Console
  2. b. Right click the Certification Authority name and click Properties
  3. c. Click the “Extensions” tab
  4. d. Document the distribution points configured for CRL Distribution Point (CDP) – as an example https://<serverDNSnname>/CertEnroll/<CANAME>CRLNameSuffix><DeltaCRLAllowed>.crl which refers to local IIS installed on the server, or https://pki.contoso.com/Certenroll/<CAName><CRLNameSuffix><DeltaCRLAllowed>.crl

Note: Ignore the LDAP and C:\%windir% locations

  1. e. In the “Extensions” tab, select Authority Information Access (AIA) from the drop down menu
  2. f.  Document the distribution points configured for the AIA extensions – as an example https://<ServerDNSName>/Certenroll/<ServerDNSName>_<CAName><CertificateName>.crt which refers to the local IIS installed on the server or https://pki.contoso.com/Certenroll/<ServerDNSName>_<CAName><CertificateName>.crt

Note: Ignore the LDAP and C:\%windir% locations

3- Disable Delta CRL and Issue a long Certificate Revocation List (CRL)

  1. a. Open the Certification Authority Console
  2. b. Right click “Revoked Certificates”, and then click “Properties”
  3. c. Uncheck “Publish Delta CRL”
  4. d. Change the “CRL publication Interval” to 99 years and then click OK
  5. e. Open the command line with elevated privileges
  6. f.  Run Certutil –crl to issue a new Certificate Revocation List (CRL)

4- Copy the old Certification Authority’s certificate (CRT) and certificate revocation list (CRL) files to the server hosting website https://crl.contoso.com/CertData 

  1. a. On the old Certification Authority, navigate to %windir%\System32\CertSrv\CertEnroll
  2. b. Copy the Certification Authority’s certificate (CRT) and certificate revocation list (CRL) to the directory hosting https://crl.contoso.com/CertData

5- Redirect the Authority Information Access (AIA) and Certificate Revocation List (CRL) distribution points of the old Certification Authority to https://crl.contoso.com/certdata

  1. a. This can be done using an IIS redirect, or a DNS CNAME redirect to redirect Authority information Access (AIA) and Certificate Revocation List (CRL) of the old Certification Authority documented in steps 2.d and 2.f to the new web server https://crl.contoso.com/certdata

6- Document and remove all certificate templates available on the old Certification Authority to prevent it from issuing new certificates

  1. a. Open the command line with elevated privileges
  2. b. Run Certutil –catemplates > c:\catemplates.txt to document all available certificate templates at the old Certification Authority
  3. c. Launch the Certification Authority console
  4. d. Navigate to “Certificate Templates”
  5. e. Highlight all templates in the right pane, right click and then click “Delete”

At this point, the old Certification Authority can’t issue any certificates, and has all of its Authority Information Access (AIA) and Certificate Revocation List (CRL) redirected to a new web site https://crl.contoso.com/CertData The next steps will detail how to document the certificates issued by templates from the old Certification Authority and how to make them available at the new Certification Authority.

7- Identify and document the certificates issued based on certificate templates by sorting the Certification Authority database

  1. a. Highlight “Issued Certificates”
  2. b. Navigate to the right, and sort by “Certificate Templates”
  3. c. Identify the certificates issued by default certificate template types
  4. d. Identify the certificates issued by custom certificate templates – any template other than the default certificate templates mentioned earlier

8- Dump the certificates based on the default certificate template types:

  1. a. Open the command line with elevated privileges
  2. b. Run Certutil -view -restrict "Certificate Template=Template" -out "SerialNumber,NotAfter,DistinguishedName,CommonName" > c:\TemplateType.txt
  3. c. Examine the output of c:\TemplateType.txt and document all the certificates needing immediate action – i.e. requiring issuance from the new CA infrastructure if needed such as Web SSL.
  4. d. Consult with the application administrator using the certificates to determine the best approach to replace the certificates if needed

Note: Replace Template with the correct template name.

9- Dump the certificates based on the custom certificate template types:

  1. a. Open the Certification Authority Console
  2. b. Right click “Certificate Templates” and click “Manage”
  3. c. Double click the certificate template and click on “Extensions” tab
  4. d. Click on “Certificate Template Information”
  5. e. Copy the Object Identifier (OID) number – the number will look similar to 1.3.6.1.4.1.311.21.8.12531710.13924440.6111642.16676639.10714343.69.16212521.10022553
  6. f. Open the command line with elevated privileges
  7. g. Run Certutil -view -restrict "Certificate Template=OIDNumber" -out "SerialNumber,NotAfter,DistinguishedName,CommonName" > c:\CustomTemplateType.txt

Note: Replace OIDNumber with the number identified in step 9.e

  1. h. Examine the output of c:\CustomTemplateType.txt and document all the certificates needing immediate action – i.e. requiring issuance from the new CA infrastructure if needed such as custom SSL certificates.
  2. i. Consult with the application administrator using the certificates to determine the best approach to replace the certificates if needed

Note: You don’t need to take any action if the certificate was auto-enrolled because the certificate holder will renew the certificate when it expires from the new CA infrastructure.

10- Enable the Certificate Templates needed based on the results of steps 7-9 on the new Certification Authority

  1. a. Logon to the new Certification Authority as an Enterprise Administrator
  2. b. Right Click “Certificate Templates”, click “New” and then click “Certificate Template to Issue”
  3. c. Choose all the certificate templates needed in the “Enable Certificate Templates” window and click “OK”

11- <Optional> At this point you can uninstall the Certification Authority Role on the old Certification Authority

  1. a. Backup the old Certification Authority using the steps outlined in Disaster Recovery Procedures for Active Directory Certificate Services (ADCS)
  2. b. Uninstall Certificate Services from the old Certification Authority
  3. c. Decommission the server unless it is running other applications

12- Once all certificates are issued by the new infrastructure, you can safely remove all the Authority Information Access (AIA) and Certificate Revocation List (CRL) files from you infrastructure by following the steps in How to Decommission a Windows Enterprise Certification Authority and How to Remove All Related Objects and from the web server hosting https://crl.contoso.com

 

Amer F. Kamal

Senior Premier Field Engineer

Comments

  • Anonymous
    January 01, 2003
    Martin. The name you are referring to is a CA Sanitized Name and can't be changed. The only solution for the issue you have is rebuilding the CA

  • Anonymous
    January 01, 2003
    Hi Matthias, It can be the new distribution point of the new CA, or a separate distribution point hosted on another web server. Best practice for CA distribution points calls for creating a separate web site hosted on a non-CA server. You need to copy the CRL and AIA files from the old CA to the distribution point, regardless of the distribution point selected above.

    • Anonymous
      July 25, 2017
      To piggyback off of this question- I am new to a company (and IIS) and am not familiar with the environment. How would I find where http://crl.contoso.com/CertData is hosted?
      • Anonymous
        August 29, 2017
        The comment has been removed

  • Anonymous
    January 01, 2003
    James, If I understand you correctly, you are suggesting to create an offline root CA and then importing the old Enterprise Root CA database. This is a bit complicated because you have to offline the CA. The easiest approach is following the steps mentioned in this blog and starting from scratch with a 2 tier hierarchy. If certificates were issued using autoenrollment, then they will renew from the new hierarchy without any issue. This should also apply to the CA in Spain. Hope this helps!

  • Anonymous
    January 01, 2003
    Hi TuanBA.

    If you lost the Root CA, then you have to build from scratch. I am assuming a lost CA means you can't locate backups/Private Keys etc...

    • Anonymous
      January 02, 2018
      I meant i can access the CertLog and CertEnroll folders.

  • Anonymous
    January 01, 2003
    Some great pointers However I need to migrate Both my offline Root as well as my Issuing CA from 2008R2 to 2012 Servers plateform, I need some advice on what's required .

  • Anonymous
    March 21, 2012
    Hello Amer, Thanks for nice tutorial. I have question: in my domain I have offline root ca with subordinate enterprice ca. I must change root ca name, because someone dont like value "issued by". So is any way to change root ca name, renew certificate for subordinate ca and keep users certificates ? Thanks a lot for any solutions.

  • Anonymous
    July 11, 2012
    Excellent guide! We're in the situation where our 5+ years old Win2003 DC has to be decommissioned since it's OLD and does not follow proper naming standards. However, it also has Enterprise Root CA installed and I'm investigating proper actions and I will suggest to do exactly what you've recommended above. But are there ANY arguments to instead setup a new 2008R2 CA standalone domain member and try to move the CA database to that server? Looking at the still active certs there's only Domain Controller certs issued. One caveat though, there is one Subordinate CA issued to a CA in Spain. I guess if we start building a new CA structure, they will also need to build a new CA server in the new CA structure?

  • Anonymous
    January 04, 2013
    The comment has been removed

  • Anonymous
    February 12, 2014
    Hi Amerk, I hope you still reading this :) First, thank you for the guide. But I have one littel thing wich is confusing me and it is right at the beginning. 2- There is a new distribution point configured for AIA and CDP locations named http://crl.contoso.com/CertData About the new distribution point. Do you mean the new distribution Point of the new CA or do mean a separate distribution Point where I have to put the old CRLs and CRTs? Sorry for that stupid question :) Thanks in advance Matthias

  • Anonymous
    February 21, 2014
    Hello All, a very good blog, appreciated.
    I have a question about auto-enrolled certificates. When the the auto-enrolled certificates get renewed against the new active CA, do they renew keeping their original public and private key-pair. Also does the certificate subject key identifier change after the renewal process?
    Regards
    Raf

  • Anonymous
    April 17, 2014
    Thanks for your good guide. If I lost root CA, can I do step by step with your guide?

  • Anonymous
    April 22, 2014
    Hi Amerk,
    My Root CA server was turned off and moved store without backup. now, I can't find RootCA server. Maybe, this server was taken away for other goal. Pleas help me detail without causing an interruption in my business. Thank you very much!

  • Anonymous
    May 12, 2014
    Hi Amerk. I have already buit new PKI. And I did the steps in your blog. Everything have run smoothly.
    Thank you so much!

  • Anonymous
    June 18, 2014
    Excellent guide!, thanks for posting. I got a question that has nothing to do with this post, but i can't find it anywhere.
    We have and old Standard Root Certification Authorithy running on W2k3, but we are trying to start using customized templates, so we have to deploy an Enterprise CA, is there any change that i would deploy a new Enterprise "Subordinate" CA on W2008R2 but keeping the Old standard root CA on w2k3 in order to minimize the heavy task of a brand new hierarchy ? this would enable us the ability to use custom templates?
    Thanks for your time!
    regards

  • Anonymous
    August 12, 2014
    Hi Amerk,

    I just came across your great blog and I was a little too late finding it  as I did the CA migration already from 2003 to 2008. I followed the following guide but it was not as detailed as yours http://blogs.technet.com/b/meamcs/archive/2012/03/27/migrating-windows-2003-enterprise-certificate-authority-to-windows-2008-r2-based-ca.aspx

    So this where I stand now; the new 2008 AD/CA server has a different host name than the old CA server name and after I did the migration to the new 2008 CA host name it took the name of the old server host name and would like to know if there is a way to change this or if I just leave it as is would it cause issues?

    The new CA server name seems functional as far as I can tell. Do I need to perform steps listed in your great guide? Should I restore/revert to the old CA server and start over with your guide, is this possible?

    I have 4 certs that are “Subordinate Certification Authority (SubCA) and just want to make sure they are being issued from the new CA server. How do I determine that?

    P.S New 2008 CA server is an Enterprise CA.

    Thank you

  • Anonymous
    April 03, 2015
    The comment has been removed

  • Anonymous
    July 08, 2015
    Thanks for this guide, Amerk!

    Perhaps you can help me in with a problem I am facing right now.
    Acutaly I am in the process of renewing a local PKI, because the old PKI is installed on old servers with a SHA1 key.

    We would like to set up a new PKI on new machines with new keys. This means, we would have two Enterprise PKI at the same time within our AD Domain.

    Our clients authenticate against our WiFi using machine certificates via a radius server. So far so good.

    Do we have to set up a new radius server, or will the old one be able to trust both certificate authorities and authenticate our clients against the old and the new CA at the same time?

    We would like to stop the autoenrollment on the old CA and enable it on the new one, and within 90 days, the old certificates will not be valid anymore. 90 days is the configured validity period for our computer certificates.
    After 90 days, we would remove the old CA.

    Is this a valid scenario?

    Thanks for your help in advance!

  • Anonymous
    August 11, 2015
    Amer,
    We have a CA in our hosted exchange domain. Other than what is automatically issued, we don't have any special certificates being requested or issued. The issued certs seems to all be domain controller and web server certs that we never really asked to be issued.
    At this point, we want to move off the current server to the new server. Do we still have to go through migrating it or can we just uninstall it and then install a new CA in the domain. Do we absolutely need a CA in the domain?

  • Anonymous
    August 21, 2015
    The comment has been removed

  • Anonymous
    September 21, 2015
    We currently have an Enterprise CA running on Server 2008 R2 that was migrated from 2003, so it is a CSP. Would I be able to follow these steps if I want to commission a new Enterprise CA (KSP) and transfer all CA functionality to the new KSP, with the ability to issue SHA256 certs etc?

  • Anonymous
    November 12, 2015
    great post from your hands again. I loved the complete article. By the way nice writing style you have. I never felt like boring while reading this article. I will come back & read all your posts soon. Regards, Lucy.

  • Anonymous
    January 14, 2016
    Hi Amer, thank you for the guide. I am looking to decommission an our old WK2003 root CA and create a new 2012 root CA, I am not looking to migrate the database across as I want to change the server name but I was under the impression you had to demission the old one first, but I guess that's not the case? So do I just create a new root CA then follow your guide to decommission the old one and switch to the new one?

  • Anonymous
    August 26, 2016
    In a scenario where the Domain Controller template through which certs were issued on all DCs is disabled on the old enterprise root CA (single tier PKI) and enabled on the new subordinate issuing CA (parallel 2 tier pki), will the DCs get the new certs through the Domain Controller template only after the old certificate expires? if yes and we don't want to wait till the cert for all DCs expire, do we have to revoke the cert on the DC or delete it from the personal store? In this case, we don't want to use any of the v2 templates on the new CA.

  • Anonymous
    November 17, 2016
    We upgraded our CA from Windows 2003 quite some ago and everything has been functioning normally but just now we need to create new server/client certificates and are unable to do so. Templates are not available. We have searched for a resolution for this and have verified some of the answers with no results. It looks as though we will have to rebuild or better yet create a new CA (server 2012 preferably). Does anyone have a procedure on completing this as we need these certificates.

  • Anonymous
    November 18, 2016
    Hi, excellent guide! Can I use it as an approach where 2 PKI exist in parallel?

  • Anonymous
    December 08, 2016
    Trying to understand if these steps are absolutely NEEDED if I am migrating my CA from one server to another server that has a different computername. (or if they're only needed in certain situations?). Please advise.

  • Anonymous
    December 09, 2016
    Thanks for this! In your scenario, how do member computers,that trusted the old CA chain, trust the new CA chain? Wouldn't you need to use a GPO to deploy the Root CA and Sub CA as Trusted to the member computers? Or is that step handled auto-magically by deploying an AD integrated CA? Thanks again!

  • Anonymous
    December 15, 2016
    Hello, are these steps absolutely REQUIRED when I migrate the CA services from Server A to Server B, where the computer-name itself CHANGES? (From what I read, I can still migrate CA services to a server with a new computername, but the CA-name itself still needs to be the same when installing the CA services).

    • Anonymous
      February 23, 2017
      Leaving the computer name the same allows for the ACL's on objects in the directory to continue to be used. If you change the name you still need to maintain the old CRL locations in LDAP if you leveraged it and they are in a container with the Old CA Hosts name.

  • Anonymous
    February 06, 2017
    The comment has been removed

    • Anonymous
      February 23, 2017
      Hello Colin, sorry for the delay....Yes, they should be kept and placed in the new location so signature and CRL checks can continue for certificates that are still out there.

  • Anonymous
    February 13, 2017
    Hi Amer, thanks for this awesome article. It clarifies a number of the specific steps in this process.Do you have any advice for dealing with non Auto-Enrolled certificates (such as certificates issued to NPS and/or Cisco ACS for use in PEAP authentication, or certificates enrolled to non-Domain joined devices)?I have a legacy PKI (2-tier) that is trusted by many legacy devices in a particular division involving lots of mobile & roaming devices, and a new 3-tier enterprise PKI that supports the whole organisation. I know I can relegate the old CA so that no new certificates are issued, but we have a large legacy of devices that are enrolled in the OLD PKI, For instance, can I have the new DivisionA SubCA "cross-signed" by the old root CA? So that all new devices (and re-configured devices) trust the new PKI, and old (legacy/not-yet configured) devices can use the new PKI because it is trusted (signed) by the old Root-CA?We have several hundred sites using the old CA, and many thousands of BYO & non-managed devices that trust the old Root CA. The process of installing the new CA certificate into the trusted certificates store of these devices will take many, many months.As these certificates are used for 802.1x authentication, and the NPS/ACS authenitcation servers need to be upgraded on the New PKI, finding a solution for this is quite important for us.Thanks for any assistance/advice you can offer. (I am hoping I am overlooking an simple solution - because qualified subordiation looks overly complicated for this task)

  • Anonymous
    March 30, 2017
    Hi Amerk,We need to migrate Enterprise CA from a Domain Controller (2003 R2 x64) to a new DC (2008 Sp2 x64). Both DC's have different host names, can i still migrate and how do i maintain same CA name (I read its required). Thanks

    • Anonymous
      April 24, 2017
      It is not required, you just need to make sure you update the ACL's on the CDP locations in LDAP (if you use LDAP) so the new CA can write to the existing objects. It is doable. You just have to watch out for the %2 in your CDP locations as this will put the servers name in it and you are changing it. Make sure when you are finished moving the CA to a server with a new name that you are able to validate all your CDP and AIA locations from a new certificate and an old certificate using: certutil -urlfetch -verify
      • Anonymous
        April 27, 2017
        Hiya,We have 2008R2 DC with Enterprise CA installed. We want to migrate the CA to a new member server, with a different name.There is this article to follow by MS https://technet.microsoft.com/en-us/library/cc742388(WS.10).aspxBut I'm concerned about clients renewing there certificates, or authenticating and not finding the CA(CDP and AIA extensions)Can the article on this site be followed, or do I follow the article Ive mentioned above?what do I do about the CDP and AIA extensions?
        • Anonymous
          May 12, 2017
          Hi Michael,This blog here is a (rather quick) way to completely decommission a CA. If I got you right you want to migrate your existing CA, though. Therefore, the guide you identified at https://technet.microsoft.com/en-us/library/cc742388(WS.10) will most likely be more suitable for you. Regarding the CDP and AIA extension please be aware that consumers expect to find the CRL and AIA information for currently issued certificates at the same locations also after the CA has been migrated. Therefore you will most likely need to modify the CA’s configuration to match the paths that were active on the CA before you did the migration. If you compare the Registry-settings on the machine where it is currently running to the settings after the migration the explanation of the different variables here might help: https://technet.microsoft.com/en-us/library/hh831574(v=ws.11).aspx. It might mean that you have to replace a variable like %2 with a hard coded string, e.g. if the server’s name, on which the CA runs changes.Hint: Also please be aware that issuing a CRL that is valid for a very long time might mean that consumers cache it for this time span and therefore might not check for a new CRL with updated revocation info during that time span.

  • Anonymous
    November 01, 2017
    Hi,Could the procedure in this blog be used if you are moving from a stand alone RootCA with NDES to a two-tier setup, with a stand alone RootCA and an Enterprise SubCA with NDES?The parts about the certificate templates would of coarse have to be omitted. But are there any other changes (additions) you have to consider? Like the AIA and CDP extensions or such?

    • Anonymous
      December 28, 2017
      Hi Kristofer,a lot of the steps outlined in this blog post may be useful for decommissioning a standalone CA as well. You seem to want to decommission a Root-CA, therefore you also need to think of ways to remove trust to it on all certificate consumers.For NDES you will need to take additional steps to decommission your existing server and install this role to another server that will most likely need you to make changes to your MDM configuration. Therefore, for specific information for your scenario the Technet Forums might be a good starting point. Please be aware that it is recommended to not run NDES and the CA role on the same machine in most cases.Best regards

  • Anonymous
    November 20, 2017
    Hi Amer,Can the new server have a different name than the old server, or do I have to use the same old server name?Thank you,Mostafa Salaam

    • Anonymous
      November 20, 2017
      Yes, the new server can have a different name.