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Creating a StartSSL SSL Certificate for Azure

Creating an SSL certificate for a website is a necessary task, but one may be infrequently completed. Because of this I always seem to forget how to generate and install my SSL certificate properly. StartSSL has been my go to certificate authority because of the suggestions by Troy Hunt. They are very inexpensive however their website isn’t the most intuitive. That being said I usually forget the steps I need to follow to create an SSL cert for a new site so as a reminder I created these quick and dirty steps for creating and using a certificate with StartSSL for an Azure website. I am not security expert so comment below if you know of a better or more secure method.

  1. Generate StartSSL Cert
    • Authenticate with http://startssl.com
    • Go to the Certificates Wizard tab, choose the web server target and continue
    • Choose and confirm a password, select the largest key size, select SHA2 and continue
    • Save your generated private key and continue
    • Select your domain. (You should have validated a domain at this point)
    • Select the domain and sub-domain you want to use (typically domain.com and www.domain.com) and continue
    • Continue and wait for approval
    • Go to the Tool Box tab and click Retrieve Certificate
    • Select the certificate you want to retrieve and continue
    • Save your certificate
  2. Generate the PFX for Azure (note: this may not be the most secure way to generate the pfx, but it works for me)
    • Go to the Tool Box tab and click on Create PKCS#12
    • Enter your private key, certificate and password for the private key and continue
    • Get PFX and the p12 file will be downloaded to your computer
    • Change the file extension to .pfx http://akbarahmed.com/2011/11/04/convert-p12-to-pfx/
  3. Add PFX to Azure
    • Open the Azure portal
    • Select the website you need the cert on
    • Click on the configure tab
    • Click upload certificate and find your pfx and enter the private key password and continue
    • If all goes well your certificate is now available for your website
    • Under SSL Bindings choose your domain to secure, choose the certificate you just uploaded and choose the ssl type. (IP Based is only available for Standard hosting)
    • Repeat for all domains that need to be secured.
    • Save

I started this process when I needed to swap my old SHA1 cert to a SHA256 cert. After installing the cert and setting it in the portal my site still served the old cert. I thought it was a bug in the portal and tried to restart my server, stop it and start it and delete the old cert (didn’t work because I had another server using it), but I still thought that there was a bug in Azure so I created a post on their forum in hopes that someone would help me out. After creating my post I noticed a “Search related threads” link at the top of the page that lead me to this thread Sporadic wrong certificate being served This thread suggested that your A record IP needs to match the virtual IP given to the website. I had overlooked this point an as soon as I set my A record correctly the correct certificate was serve.

Another setback I experienced was that StartSSL was using a SHA1 intermediate certificate. I didn’t really know how intermediate certificates worked so I leveled up my knowledge here Unfortunately I haven’t been able to figure out how to remove the old intermediate certificate without re-creating a new website. I’ll update this as soon as I get some support from Azure.

Update: I guess this was an Azure bug. Eventually my site was updated and it started serving the correct intermediate certificate. All is well.