Tag Archives: PEM

Azure VPN: Point To Site VPN (Remote Access)

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KB ID 0001692

Problem

Given my background I’m usually more comfortable connecting to Azure with a Route Based VPN from a hardware device, like a Cisco ASA. I got an email this afternoon, a client had a server in a private cloud and a server in Azure, they needed to transfer files from the Azure server to the server in the private cloud. Now on further investigation this client had a Cisco vASA so a VPN was the best option for them, (probably).

But what if they didn’t? Or what if they were ‘working from home’ and needed to access their Azure servers that were not otherwise publicly accessible?

Well the Microsoft solution for that is called an ‘Azure Point to Site VPN‘, even though in the current Azure UI they’ve called it ‘User VPN Configuration‘, because ‘Hey! Screw consistency and documentation that goes out of date every time a developer has a bright idea, and updates the UI’ Note: I have a thing about things being changed in GUIs!

So regardless whether you are on or off the corporate LAN, you can connect to your Azure Virtual Networks.

Azure VPN (Remote Access)

This is not a full Azure tutorial, I’m assuming, as you want to connect to existing Azure resources, you will already have most of this setup already. But, just to quickly run through. You will need a Resource Group, and in that Resource Group you will need a Virtual Network. (Note: I like to delete the ‘default‘ subnet and create one with a sensible name).

So far so good, within your virtual network you will need to create, (if you don’t already have one,) a ‘Gateway Subnet‘. To annoy the other network engineers, I’ve made it a /24, but to be honest a /29 is usually good enough).

Now to terminate a VPN, you need a ‘Virtual Network Gateway‘.

Make sure it’s set for VPN (Route Based) > Connected to your Virtual Network  > Either create (or assign) a public IP to it. I told you I’d be quick, however the Gateway will take a few minutes to deploy, (time for a coffee.)

Azure VPN Certificate Requirement

For the purpose of this tutorial I’ll just create some certificates with PowerShell, (a root CA cert, and a client cert signed by that root certificate). This wont scale very well in a production environment. I’d suggest setting up a decent PKI infrastructure, Then using auto-enrolment for your users to get client certificates. However for our run through, execute the following TWO commands;

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$cert = New-SelfSignedCertificate -Type Custom -KeySpec Signature -Subject "CN=Azure-VPN-Root-Cert" -KeyExportPolicy Exportable -HashAlgorithm sha256 -KeyLength 2048 -CertStoreLocation "Cert:\CurrentUser\My" -KeyUsageProperty Sign -KeyUsage CertSign

New-SelfSignedCertificate -Type Custom -DnsName Azure-VPN-Client-Cert -KeySpec Signature -Subject "CN=Azure-VPN-Client-Cert" -KeyExportPolicy Exportable -HashAlgorithm sha256 -KeyLength 2048 -CertStoreLocation "Cert:\CurrentUser\My" -Signer $cert -TextExtension @("2.5.29.37={text}1.3.6.1.5.5.7.3.2")

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Now launch ‘certmgr‘ and you will see the two certificates. Firstly, export the client certificate.

Yes you want to export the private key > You want to Save it as a .PFX file > Create a password for the certificate (MAKE NOTE OF IT!) > Save it somewhere you can get to, (you will need it in a minute).

Secondly, export the Root CA certificate.

 You DON’T export the private key > Save as Base-64 encoded > Again save it somewhere sensible, you will also need it in a minute.

Open the ROOT CA CERT with Notepad, and copy all the text BETWEEN —-BEGIN CERTIFICATE—- and —-END CERTIFICATE—- Note: This is unlike most scenarios, when working with PEM files, where you select everything, (it tripped me up!)

Back in Azure > Select your Virtual Network Gateway > Select ‘User VPN Connection’ (seriously, thanks Microsoft be consistent eh!) > ‘Configure now‘.

Pick an address pool for your remote clients to use, (make sure it does not overlap with any of your assets, and don’t use 192.168.1.0/24, or 192.168.0.0/24, Note: These will work, but most home networks use these ranges, and let’s not build in potential routing problems before we start!)

Choose IKEv2 and SSTP > Authentication Type = Azure Certificate > Enter your Root CA details, and paste in the PEM text, you copied above > Save > Time for another coffee!

When is stopped deploying, you can download the the VPN client software.

Azure Point to Site (User VPN) Client Configuration

So for your client(s) you will need the Client Certificate, (the one in PFX format,*) and the VPN Client software >  Double click the PFX file > Accept ‘Current User‘.

*Note: Unless you deployed user certificates already, and your corporate Root Cert was entered into Azure above.

Type in the certificate password you created above > Accept all the defaults.

Yes.

Now install the Client VPN software, you may get some security warnings, accept them and install.

Now you will have a configured VPN connection. I’m a keyboard warrior so I usually run ncpa.cpl to get to my network settings, (because it works on all versions of Windows back to NT4, and ‘developers’ haven’t changed the way it launches 1006 times!)

Launch the Connection > Connect > Tick the ‘Do not show…‘ option > Continue > If it works, everything will just disappear and you will be connected.

Related Articles, References, Credits, or External Links

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Cisco PRSM – Replace the Certificate Using Microsoft Certificate Services

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KB ID 0001023 

Problem

Cisco PRSM gives you the ability to import certificates into it, but like other Linux distros does not give you the tools to generate the actual certificate request. The documentation tells you to use OpenSSL to this. I was just about to fire up a CentOS box when I remembered I did something similar for VMware 5.5 not so long ago, would the same procedure work here? Yes it did, and it’s a lot easier than growing a ginger ponytail, donning sandals and firing up Linux.

Solution

The following procedure was carried out on Windows Server 2012 R2. I want my certificate to have a common name of prsm.petenetlive.com (change your configs and commands accordingly).

1. Download and install the following.

Microsoft Visual C++ 2008 Redistributable Package (x86) and Shining Light Productions installer for OpenSSL x86 version 0.98r (or later)

2. Accept all the defaults and it should install to C:OpenSSL-Win32 go there, and in the bin directory make a backup of the openssl.cfg file.

2. Open the original openssl.cfg file and delete everything out of it, then paste in the following text, replace the values in red with your own, and save the file.

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[ req ]
default_bits = 2048
default_keyfile = prsm.petenetlive.com.key
distinguished_name = req_distinguished_name
encrypt_key = no
prompt = no
string_mask = nombstr
req_extensions = v3_req

[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = digitalSignature, keyEncipherment, dataEncipherment
extendedKeyUsage = serverAuth, clientAuth
subjectAltName = DNS:PRSM, IP:123.123.123.110, DNS:prsm.petenetlive.com

[ req_distinguished_name ]
countryName = GB
stateOrProvinceName = Teesside
localityName = Middlesbrough
0.organizationName = PeteNetLive
organizationalUnitName = Technical Services
commonName = prsm.petenetlive.com

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3. Open an administrative command window, issue the following three commands;

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cd C:OpenSSL-Win32Bin

openssl req -new -nodes -out prsm.petenetlive.com.csr -keyout prsm.petenetlive.com-orig.key -config openssl.cfg

openssl rsa -in prsm.petenetlive.com-orig.key -out prsm.petenetlive.com.key

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Don’t worry if it says it cant read the openssl.cnf file

4. If you look in C:OpenSSL-Win32bin directory you will see the CSR (certificate request) has been generated.

5. Open the .csr file with notepad and copy all the text, (this is a request in PEM format). This is what you will give to your CA to request the certificate, copy that to the clipboard.

6. Connect to your Certificate Authority web enrollment portal > Request a certificate.

7. Advanced certificate request.

8. Submit a certificate request by using a base-64-encoded CMC or PKCS #10 file, or submit a renewal request by using a base-64-encoded PKCS #7 file.

9. Paste in the PEM text you copied to the clipboard > Set the certificate template to ‘Web Server’ > Submit.

Note: Your CA may have a different template for web server certificates, if so use that one. If you don’t see web server either it’s not been published, or your user does not have rights to the certificate template.

10. Choose ‘Base 64 encoded’ > Download > Save the cert in the directory you were using earlier (you will see why in a minute) > I give it the same name as the common name on the certificate so I saved it as prsm.petenetlive.com.cer

11. Here it is, but there is still a problem with it, PRSM needs the certificate in x509 format, (it isn’t). But OpenSSL-Win32 can convert it for us.

How to Convert a Windows .cer file to an x509 .crt file

12. Open and administrative command window and issue the following two commands;

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cd C:OpenSSL-Win32bin
openssl x509 -in prsm.petenetlive.com.cer -out prsm.petenetlive.com.crt

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13. Now it looks better, for PRSM we need this file AND we need the .key file, (not the one that ends in xxx-orig.key!) In the example below I’ve kept everything neat so the other file i need is prsm.petenetlive.com.key, (third one down).

14. Connect to PRSM > Administration > Server Certificates > Browse and select both files.

15. Install and Restart Server.

16. Restart.

17. Refresh your web session and you should now be using the correct certificate.

Related Articles, References, Credits, or External Links

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Cisco ISE – Replace the Self Signed Certificate

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KB ID 0001068 

Problem

Cisco ISE arms itself with a self generated certificate out of the box, (well the NFR appliance does anyway). To replace that cert with one signed by your own CA, this is the procedure. (Note: I’m using Microsoft Certificate Services on Server 2012 R2).

Solution

Step 1: Import the CA Certificate into ISE

Note: If you have a lot issuing servers it’s a good idea the repeat this procedure for EVERY issuing server you have in your PKI environment. Assuming you have an off-line root that would be every SubCA (to use Microsoft terminology). On my test network I only have one so that’s not a problem.

1. Connect to the web enrollment portal of your Certificate services folder > Download a CA Certificate, certificate chain, or CRL.

2. Select DER encoding > Download CA Certificate.

3. Save the certificate where you can find it, with a sensible name.

4. Log into ISE > Administration > System > Certificates > Certificate Store > Import.

5. Import the certificate you just saved and tick the ‘Trust for client authentication or secure Syslog services’ option > Submit.

Step 2: Generate a New Certificate for Cisco ISE

6. Whilst still in the certificate section > Local Certificates > Add > Generate Certificate Signing Request.

7. Enter the FQDN of the ISE appliance > Submit.

8. Certificates > Certificate Signing Requests > Export.

9. Again save it somewhere you can find it easily.

10. Open the PEM file you just created, and copy all the text to the clipboard.

11. Back at you web enrollment portal > Request a certificate.

12. Advanced certificate request.

13. Submit a certificate request by using…

14. Paste in your copied text (make sure no spaces get added to the end, this usually happens, be careful) > Set the template to Web Server (of your own template, if you are not using the default one) > Submit.

15. Select DER encoded > Download certificate > Save it with a name that is recognizable as the ISE appliance.

16. On the ISE web portal > Local Certificates > Add > Bind CA Signed Certificate.

17. Browse to the new cert > Select EAP and HTTPS > Submit.

18. Now remember to connect to the ISE appliance using its FQDN (you did remember to create a record in DNS for it didn’t you?)

At this point if you get an error either the URL is wrong, or you didn’t create a DNS record, or the machine you are on does not trust your issuing servers root certificate.</p?

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Cisco ASA 5500 – Using a Third Party Digital Certificate

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(For Identification, AnyConnect, and SSL VPN)

KB ID 0000694

Problem

A client asked me how to do this, so off I went to the test bench to work it out.

Note: I’m this example In going to submit the request to, and issue the certificate from, my own windows domain certificate authority, you would send your request to a third party certificate authority, here’s a direct link to the certificate type you require. To use your own CA every client connecting to the ASA would need to trust this CA.

Solution

Certificates are date specific, so we need to make sure your firewall knows the correct date and time.

1. Connect to the ASA via ASDM > Configuration > Device Setup > System Time > Set the time and time zone correctly.

Note: As shown, from command line simply enter “show clock”.

2. Configuration > Device Management > Certificate Management > Identity Certificates > Add > New > Supply a key pair name > Generate Now.

Note: If using Digicert change the Key Size to 2048 or you will see this error, when you attempt to get your certificate.

Something is wrong
The CSR uses an unsupported key size, please generate a new CSR with a key size of at least 2048 bits.

3. Select > Set each attribute, and add it one by one (as shown) > OK.

4. Advanced > Set the FQDN to the SAME name you entered for the CN in step 3 > OK > Add Certificate.

5. Choose a location to save the certificate request.

6. Locate and open the certificate request and it should look something like this.

Note: This is the information your certificate vendor will require.

7. Once your request had been processed the certification authority should send you a certificate. (Note: some vendors may send you a text file that you need to rename from filename.txt to filename.cer before it will look like this).

8. With the certificate open (as above) > Certificate path > Select the the Issuing Certificate Authority > Copy to File.

Note: You need to import the root certificates, and depending on the vendor, any intermediate certificates, I’ve shown an example from two major vendors to illustrate.

9. Select “Base-64 encoded…” > Next.

10. Save the cert somewhere you can find it.

11. Open it with notepad, and it should look like this > Select ALL the text.

12. Back at the ASDM > Configuration > Device Management > Certificate Management > CA Certificates > Add > Paste certificate in PEM format > Paste in the text > Install Certificate.

13. Repeat the process for any other RootCA or Intermediate Certificates. Then you will need to go back to step 8 and export the web certificate itself, (i.e. in this case select vpn.petenetlive.net and export that to file, and copy that from notepad to the clipboard).

14. Back in the ASDM this time you will need to install the Identity Certificate, (this is the one you paid for!) > Select the pending request from earlier > Install > Paste in the text > Install Certificate > Apply.

15. To enable the certificate on the outside interface > Configuration > Device Management > Advanced > SSL Settings > outside > Edit > Select the new one from the list > OK > Apply.

16. Note: If you were configuring your AnyConnect VPN’s later this is the point in the setup, where you would select the new certificate.

17. Make sure you can resolve the name that’s on the CN of your certificate and you can reach it from a client machine.

18. Now you should be able to connect without certificate warnings.

19. Don’t forget to save the settings on your ASA (File > Save Running Configuration to Flash).

Related Articles, References, Credits, or External Links

Securing Cisco SSL VPN’s with Certificates

Cisco ASA – Cannot Enable Third Party Certificate (9.4 and later)