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Beginner

SSL Certificate *renewal* instructions

I can't seem to find clear instructions for installing a RENEWED ssl certificate on an ASA.  All of the instructions I see talk about generating the CSR from the ASA but what about when a customer renews their SSL cert through a popular vendor such as GoDaddy or DigiCert?  They are not using a CSR generated by the ASA so how in the heck do I get the new cert installed??  

 

Also, nobody (and I mean nobody) has been able to demonstrate how to install a wildcard cert to an ASA. The ASA will not allow an asterisk (*) as part of the FQDN or CN.  

 

Please don't just post some link to a cisco doc, *explain* it to me because I guarantee I've already read any cisco doc you are about to link. 

 

As you can imagine, I'm very frustrated at this point.

 

Thanks,

John

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1 ACCEPTED SOLUTION

Accepted Solutions
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Hall of Fame Guru

Re: SSL Certificate *renewal* instructions

You can install a wildcard certificate on an ASA. You just cannot create a CSR for a wildcard using the ASA.

When installing the wildcard certificate (or renewed certificate) you must have the private key used to request the wildcard (or the original wildcard in case of a renewal). Often we do this with OpenSSL making the key easy to save.

When you have the wildcard certificate and key in a PKCS12 file, just add them as a new identity certificate as shown below and then choose that new certificate instead of the old one under your remote access VPN configuration. As you can see in the screenshot, my ASA currently has a wildcard certificate installed.

ASDM Wildcard.PNG

View solution in original post

18 REPLIES 18
Highlighted
VIP Advisor

Re: SSL Certificate *renewal* instructions

Hi 

 

First of all I'm not very comfortable with asdm and maybe it could be easier if someone else can help you on that topic. 

 

There's no kind of renewal certificate procedure. 

Let me explain: 

- need to create a new trustpoint

- get your provider root and intermediate 

- having your cert and your private key 

- using openssl to make a pkcs12 certificate 

- authenticate your trustpoint with your provider cert 

- import your pkcs12 cert into your trustpoint 

- use the command ssl trust-point to change from your old to your new certificate. 

 

Create trustpoint

crypto ca trustpoint mywildcardcert.com

  fqdn xxx.company.com

  enrollment terminal

  revocation-check none

 

Authenticate your trustpoint:

 

crypto ca authenticate mywildcardcert.com

 then copy/paste your CA authority cert

 

-----BEGIN CERTIFICATE-----

Your CA authority certificate (usually you receive a bundle containing the root and subca)

-----END CERTIFICATE-----

quit

 

Then you need to accept the certificate and you should get the message that trustpoint ca is accepted and certificate has been imported. 

 

Openssl stuff: i recommend you to do it on a Linux or mac machine (like Ubuntu vm if you don't have any mac or Linux machine)

 

cat RootCA.pem Intermediate.pem > root.crt 

 

openssl pkcs12 -export -in wildcardcert.pem -inkey wildcardKEY.pem -certfile root.crt -out mycertwildcardexport.p12

 

It'll prompt you for a password. Choose something complexe for security purpose but don't lose it as you'll need it on the next step. 

 

cat mycertwildcardexport.p12 | base64

 

Import on ASA

crypto ca import mywildcardcert.com pkcs12 secret-defined-before

 

Paste all content of your p12 file created before then type quit on the next empty line. 

 

You'll get prompted if you want to import all cert hierarchy. Answer yes. 

 

Last, assign it to your outside interface

ssl trust-point mywildcardcert.com outside

 

If you want to validate it, you can use openssl:

openssl s_client -connect your-fqdn-vpn:443

 

Let me know how it went. 

 

Thanks 

 

PS: Please don't forget to rate and select as validated answer if this answered your question

 


Thanks
Francesco
PS: Please don't forget to rate and select as validated answer if this answered your question
Highlighted
Beginner

Re: SSL Certificate *renewal* instructions

Hi Francesco,
I appreciate you taking the time to lay out all the steps. There is some helpful information in your post but not exactly what I was looking for.

Thank you for your effort.

Highlighted
VIP Advisor

Re: SSL Certificate *renewal* instructions

Hi John

Sorry I was thinking that you were searching for "how to import wildcard certificate" on ASA. Sure it was through CLI and not ASDM.

thanks

Thanks
Francesco
PS: Please don't forget to rate and select as validated answer if this answered your question
Highlighted
Hall of Fame Guru

Re: SSL Certificate *renewal* instructions

You can install a wildcard certificate on an ASA. You just cannot create a CSR for a wildcard using the ASA.

When installing the wildcard certificate (or renewed certificate) you must have the private key used to request the wildcard (or the original wildcard in case of a renewal). Often we do this with OpenSSL making the key easy to save.

When you have the wildcard certificate and key in a PKCS12 file, just add them as a new identity certificate as shown below and then choose that new certificate instead of the old one under your remote access VPN configuration. As you can see in the screenshot, my ASA currently has a wildcard certificate installed.

ASDM Wildcard.PNG

View solution in original post

Highlighted
Beginner

Re: SSL Certificate *renewal* instructions

This was exactly what I needed to know.  Thank you!

Highlighted
Hall of Fame Guru

Re: SSL Certificate *renewal* instructions

You're welcome. Glad I was able to help - thanks for rating!
Highlighted
Beginner

Re: SSL Certificate *renewal* instructions

Do I have to delete the old cert?  I added my new wildcard cert and saved it but I am getting the cert expiration warning when VPN'ing into my environment.

Highlighted
Enthusiast

Re: SSL Certificate *renewal* instructions

You need to select the new cert you imported to be used. Sounds like
although you imported the new cert, it’s sitting idle and the VPN config is
still using the old cert.
Highlighted
VIP Advisor

Re: SSL Certificate *renewal* instructions

You need to select the new certificate and then you can delete the expired one

Thanks
Francesco
PS: Please don't forget to rate and select as validated answer if this answered your question
Highlighted
Beginner

Re: SSL Certificate *renewal* instructions

You just need to assign the enrolled SSL trustpoint to the interface you're using for Anyconnect termination.  

 

CLI:

ASA (config)# ssl trust-point <trustpoint name> <interface>

 

ASDM: 

Configuration/device mgmt/advanced/SSL settings:  select the interface and click on "edit" then select the "primary enrolled certificate" dropdown, select your new cert and then click OK.  Don't forget to apply and save the new config. 

 

You're done. 

Highlighted
Explorer

Re: SSL Certificate *renewal* instructions

Hello, I am looking to renew an upcoming expire SSL certificate used for AnyConnect. I am using a separate network device F5 to generate the CSR for the renewal request which is the same private key as the one on the ASA. How do I import just the newed certificate from the trusted external authority where I get it? The private key I am looking to keep the same. When you add a new identity certificate it walks you through creating a common name and all of the fields required to build a new certificate. I am looking to import the certificate file with the existing private key. Can you walk me thru the exact steps?
Highlighted
VIP Advisor

Re: SSL Certificate *renewal* instructions

Hi
If i understand correctly you already renewed the certificate on your F5, Right?
If so, you should have the cert and the private key, right? Then take a look on my post at the beginning of this thread, I explain how to combine a cert pem file and private key into p12 file. On asa, i also explained how to import that file and set this new trustpoint for anyconnect.

Thanks
Francesco
PS: Please don't forget to rate and select as validated answer if this answered your question
Highlighted
VIP Advocate

Re: SSL Certificate *renewal* instructions

Beginner

Re: SSL Certificate *renewal* instructions

Hi Marvin, I thought I would just add this here as it may be helpful.

You talk of importing the keys and new cert from a pkcs12 file. In my case I did not have a pkcs12 file or a private key file.

I thought I would add if you just have .crt file from the renewed certificate the same as previously requested. Just change the radio button to add new, choose the same key-pair used in the existing trustpoint.

eg:

crypto ca trustpoint ASDM_TrustPoint0
enrollment terminal
subject-name CN=vpn.yourcompany.com
keypair SSL-Keypair
no validation-usage
crl configure

The following command will tell you which trustpoint your currently using.

show run | inc ssl trust-point

eg: ssl trust-point ASDM_TrustPoint0

There may be an interface name as the 4th parameter.

Once you have the certificate imported and any newer CA certs imported.

Change the above command to the new trustpoint name.

 

GoDaddy has the following helpful link.

https://ca.godaddy.com/help/manually-install-an-ssl-certificate-on-my-cisco-asa-5500-vpnfirewall-32070

 

Regards.