Product review CertHat!

Have you ever managed a Microsoft CA? Then you probably know about all the limitations in the tools for administration. For example, the problem with browsing and searching in the CA database? Or keeping track of certificates about to expire? Or just a simple thing as statistics over issued, revoked failed/denied certs? And don´t get me started about the manual enrollment options.

Well a couple of weeks ago I was contacted by a company which develops an add-on software for MS CA. The asked if I could do a review of their product and provide feedback. And since I spend a lot of time in a hotel room I decided to help out.

The product is called CertHat and provided a web-service for MS CA. It consists of a Web application, a SQL database and a small agent installed on your CA servers.

My first impression is great! It provides a really nice web interface with a lot of nice features. For example, database search, statistics, notification of expiration for certs and a lot of other really nice stuff.

More information can be found on their web site; There is a lot of info about the product. It also contains a full featured demo-site to test the product. And of course, contact info. Otherwise let me know and I´ll do my best to help out with contacts.

And just for info: I don´t get any form of payment for this blog post. I got a nice Certhat T-shirt for my testing and feedback, and that is all! I just really like the product and got a really good impression of the guys behind it. So please mention this blogpost if you decide to contact them. 🙂

Certificate Bulk Enrollment to PFX

Is it possible to provide certificates to industrial equipment that doesn’t have any enrollment capabilities?

That´s the challenge one of our customers gave us a couple of weeks ago. The certificates should be used for network access on an 802.1x network and authentication to a database. Me and my fantastic colleague Tomas accepted the challenge and went to work.

So we had to create a completely automatic enrollment process with as little user interaction as possible. Our goal was to provide the manufacturer with password protected pfx-files in a bulk with a password file, mapping the pfx-files to a randomly generated password for each pfx. First we started by doing a manual enrollment process.

Enrollment process – step by step

  •  The first step was to create an inf-file (request.inf) as input to the request file.

Signature=”`$Windows NT$

Subject =
Exportable = True
KeyLength = 4096
KeyUsage = 0xA0 ; Digital Signature, Key Encipherment
MachineKeySet = True ; The key belongs to the local computer account
ProviderName = “Microsoft RSA SChannel Cryptographic Provider”
ProviderType = 12
SMIME = False

  •  After that we used the inf-file together with certreq.exe to create a certificate request file.

Certreq.exe -new d:\request.inf d:\enroll\req\Test123.req

  •  The next step was to submit the request file to the CA and issue a certificate with certreq.exe.

Certreq.exe -submit -config “\CA01” d:\enroll\req\Test123.req d:\enroll\cer\Test123.cer

  •  After that we imported the certificate to the certificate store on the local machine with certutil.exe

Certutil.exe -addstore -f MY d:\enroll\cer\Test123.cer

  •  Then we had to match the certificate to the private key so we would be able to export the pfx-file.

Certutil.exe -repairstore MY

  •  Next step was to export the pfx from the certificate store and set a password for the private key.

Certutil.exe -password 1q2w3e4r -exportPFX d:\enroll\pfx\Test123.pfx

  •  Then we deleted the certificate and private key from the local certificate store

certutil –privatekey –delstore MY Test123

After testing this process we gave it all to our brilliant colleague Simon, which created a powershell script with some parameters, a password generator and some other nice stuff.


After testing and handover to the customer they were extremely  happy with the solution and it works perfect!

StartSSL – Free SSL certs!

Thought I´d write a short blog post about public certificates for test environments. By public certificates I mean certificates issued by an external CA and trusted by most platforms.

If you got a test or lab environment and want to publish an external service with SSL, for example ADFS, you need a certificate. This certificate must be trusted by all devices used by consumers of the service. OK, it´s a test environment so you can use you own CA to issue the certificates and import the RootCA certificate on all devices you are testing with. But I guess a lot of you out there isn´t that into certificate that you find that especially interesting. 🙂

So what are your options? You can of course buy a SSL cert from Digicert, Verisign or any other public CA. But I guess you don´t want to spend too much money on your testing. And there is another alternative.

Try (no, I´m not getting paid for this!). They are using the StarCom Class 1 CA and issues free SSL certificates. And the best part is that the CA is trusted by almost every platform no the market.


All you need to do is to create an account and you´re on! There are of course some restrictions. For example you can´t issue SAN (Subject Alt Name) certs for free, the validity period is only 1 year, no EV certs for free for example. But If you just are using it for test/lab your fine!  (And I rebuild my test environment a couple of times a years so I don´t see any real drawbacks!

A comparison chart of their certificates can be found here:

Well, that´s all for now folks! 🙂

Killer feature in IIS 8.5!

Certificate Rebind in IIS?

So what is it then? It´s a function to automaticlly replace an SSL certificate bound to a web site. If the certificate is renewed then the old one will be replace with the new one. Great isn´t it?


How does this work?

When you enable Certificate Rebind a task will be added to the Task Scheduler which is triggered by the event ID for certificate renewal (event ID 1001). And when a certificate is renewed a function called “Certificate Services Lifecycle Notifications”, which keeps track of certificate releated stuff, writes the renewal event to the event log and the rebind process starts. It simply provides appcmd.exe with the thumbprint of the expired and new certificate.

Then appcmd locates all websites on that server which uses the old cert. It unbinds the old cert and binds the new certs to the affected websites. And this works for both manually and autoenrolled certificates.

If you are really interested this is the command line:

appcmd.exe renew binding /oldcert:$(OldCertHash) /newcert:$(NewCertHash)


What triggers Event ID1001?

EventID 1001


•  Action (see sources column)

For old and new certificate:

•  Template

•  Subject names

•  EKUs

•  Thumbprint

• Renewal via autoenrollment (action=renew)

• Enrollment for a superseding (action=supersede)

• Renewal via MMC enrollment (action=renew)

• Renewal via certreq.exe (action=renew)

• Manually replacing on cert with another using Replace-Certificate PowerShell CmdLet (action=replace)


Note: If you want to use autoenrollment and the cert got a DNS name och SAN-attribute you have to enable “Use subject information from existing certificates for autoenrollment renewal requests” on the template.


Can this be done any other way and on other systems then IIS?

Sure! By using Powershell you can create custom tasks which is triggered by events created by “Certificate Services Lifecycle Notifications”


More info:

An excellent article on certificate rebind can be found here:

How to renew web server certificates automatically?

Certificate Services Lifecycle Notifications


But be aware! There are some pitfals and you should have some kind of idea about what you are doing! And remember: Keep it simple!!