Tag: certificate

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Error from Filezilla Client to Microsoft IIS FTP Server

When you connect to ftp server create with Microsoft IIS using Filezilla Client you should have this error

GnuTLS error -48: Key usage violation in certificate has been detected. Could not connect to server

Your configuration settings are something like this :

  • Protocol: FTP – File Transfer Protocol
  • Encryption: Require explicit FTP over TLS

The problem is with self signed certificate on server side. This is a problem with the certificate generation of Microsoft IIS, as it does not allow the certificates to be used for digital signatures.

How to generate a valid certificate with IIS

This is a server-side issue, and it did not appear previously because earlier versions of FileZilla shipped with a GnuTLS version that didn’t make this check.

Quoting Tim Kosse’s post in the FileZilla forum thread:

In any case, the problem is with your server’s X.509 certificate chain: Either the server certificate itself or another certificate in the chain has a key usage restriction that is violated. For example a certificate with a key usage restriction to signing cannot be used to authenticate TLS connections. See section 4.2.1.3 of RFC 5280.

This is a problem with the certificate generation of Microsoft IIS (but may also happen if you incorrectly generated a certificate with another method), as it does not allow the certificates to be used for digital signatures. OpenSSL is much more relaxed about this and won’t fail because of it, so it may work with other apps.

On the client side, you can either disable TLS, downgrade to an earlier version of FileZilla (neither of these is recommended due to potential security risks), or use a different client which uses another library such as OpenSSL for now.

How to generate a valid certificate with IIS

This needs to be done on the server side, Yobviously.you can generate the certificate with PowerShell instead until the issue is fixed by Microsoft. Open PowerShell in admin mode.

The following powershell command will create our self-signed certificate for our binding and store it in the Personal Store (Note how I also store a reference to the certificate in a variable called $cert this will be needed further on):

$binding = "192.168.1.70"
$cert = New-SelfSignedCertificate -DnsName "$binding" -CertStoreLocation "cert:\LocalMachine\My"

However, this is not enough to make the certificate work for HTTPS in our browser. We need to add our newly created certificate to the Trusted Root Certificate store. To do this we take our $cert variable which references our created certificate and add it to our Trusted Root Certificate store like so:

$DestStore = new-object System.Security.Cryptography.X509Certificates.X509Store([System.Security.Cryptography.X509Certificates.StoreName]::Root,"localmachine")
$DestStore.Open([System.Security.Cryptography.X509Certificates.OpenFlags]::ReadWrite)
$DestStore.Add($cert)
$DestStore.Close()

Now you have to set the new certicate on your ftp site using IIS Admin.

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Configure a Point-to-Site VPN connection via Openvpn on Azure

Create a virtual network

  1. Sign in to the Azure portal.
  2. In Search resources, service, and docs , type virtual network.
  3. On the Virtual Network page, select Create.
  4. On the IP Addresses tab, configure the values

Subnet: If you use the default address space, a default subnet is created automatically.

  • Subnet name: In this example, we named the subnet “FrontEnd”.
  • Subnet address range: The address range for this subnet.

On the Security tab, at this time, leave the default values:

  • DDos protection: Basic
  • Firewall: Disabled

So we will have this configuration (as example) :

  • Address space: 10.1.0.0/16
    Subnet name: FrontEnd
  • Subnet address range: 10.1.0.0/24

Create a virtual network gateway

  1. In the Search the Marketplace field, type ‘Virtual Network Gateway’

SKU: Select the gateway SKU from the dropdown. For Openvpn you need to select VpnGw1 because

Gateway subnet address range: This field only appears if your VNet doesn’t have a gateway subnet. If possible, make the range /27 or larger (/26,/25 etc.)

In this example :

GatewaySubnet: 10.1.1.0/27

Certificates

Certificates are used by Azure to authenticate clients connecting to a VNet over a Point-to-Site VPN connection. You have two options : use a root certificate that was generated with an enterprise solution (recommended), or generate a self-signed certificate.

Generate and export certificates for Point-to-Site using PowerShell

Two steps : generate root certificate; generate client certificate.

root certificate

From a computer running Windows 10 or Windows Server 2016, open a Windows PowerShell console in Admin mode.

Use the following example to create the self-signed root certificate. The following example creates a self-signed root certificate named ‘TestVPNRootCert’ that is automatically installed in ‘Certificates-Current User\Personal\Certificates’.

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

You can view the certificate by opening certmgr.msc, or Manage User Certificates.

client certificate

Each client computer that connects to a VNet using Point-to-Site must have a client certificate installed. You generate a client certificate from the self-signed root certificate.

From a computer running Windows 10 or Windows Server 2016, open a Windows PowerShell console in Admin mode. Identify the self-signed root certificate that is installed on the computer. This cmdlet returns a list of certificates that are installed on your computer.

Get-ChildItem -Path "Cert:\CurrentUser\My"

As output you will see a string and a name for every certificate installed on your machine.

For example :

AED812AD883826FF76B4D1D5A77B3C08EFA79F3F CN=MyOldVPNRootCert

7181AA8C1B4D34EEDB2F3D3BEC5839F3FE52D655 CN=TestVPNRootCert

Declare a variable for the root certificate using the string from the previous step:

$cert = Get-ChildItem -Path “Cert:\CurrentUser\My\7181AA8C1B4D34EEDB2F3D3BEC5839F3FE52D655”

Modify and run the example to generate a client certificate. The result of the following example is a client certificate named ‘TestVPNClientCert’

New-SelfSignedCertificate -Type Custom -DnsName TestVPNClientCert -KeySpec Signature  -Subject "CN=TestVPNClientCert" -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")

The client certificate that you generate is automatically installed in ‘Certificates – Current User\Personal\Certificates’ on your computer.

Export the root certificate public key (.cer)

To obtain a .cer file from the certificate, open Manage user certificates. Locate the self-signed root certificate, typically in ‘Certificates – Current User\Personal\Certificates’, and right-click. Click All Tasks, and then click Export. This opens the Certificate Export Wizard.

Select No, do not export the private key, and then click Next

On the Export File Format page, select Base-64 encoded X.509 (.CER)., and then click Next.

For File to Export, Browse to the location to which you want to export the certificate. For File name, name the certificate file. Then, click Next.

Click Finish to export the certificate. You’ll find a file .cer in location selected.

Export the client certificate

To export a client certificate, open Manage user certificates. The client certificates that you generated are, by default, located in ‘Certificates – Current User\Personal\Certificates’. Right-click the client certificate that you want to export, click all tasks, and then click Export to open the Certificate Export Wizard.

Select Yes, export the private key, and then click Next. IMPORTANT!!!!

On the Export File Format page, leave the defaults selected. Make sure that Include all certificates in the certification path if possible is selected

On the Security page, you must protect the private key, using a password.

On the File to Export, Browse to the location to which you want to export the certificate. For File name, name the certificate file. Then, click Next.Click Finish to export the certificate.

Add the client address pool

The client address pool is a range of private IP addresses that you specify. The clients that connect over a Point-to-Site VPN dynamically receive an IP address from this range. Use a private IP address range that does not overlap with the on-premises location that you connect from, or the VNet that you want to connect to.

Open virtual network gateway configuration page, navigate to the Settings section of the virtual network gateway page. In the Settings section, select Point-to-site configuration. Select Configure now to open the configuration page.

In the Address pool box, add the private IP address range that you want to use. VPN clients dynamically receive an IP address from the range that you specify.

For example : 172.16.0.0/24

Tunnel Type : OpenVpn

Authentication Type : Azure certificate

In root certificate section you have to put the root certificate name (in this example TestVPNRootCert).

Open the root certificate file (.cer) with a text editor, such as Notepad. Copy the text as in image and past it in “Public certificate data”

Save Point to Site Configuration.

Download vpn Client clicking on “Download vpn Client” 🙂

Install Openssl

https://slproweb.com/products/Win32OpenSSL.html

Extract the private key and the base64 thumbprint from the .pfx client certificate.

Using OpenSSL on your machine is one way. The profileinfo.txt file contains the private key and the thumbprint for the CA and the Client certificate

openssl pkcs12 -in “C:\myfolder\clientcert_vpn_test.pfx” -nodes -out “C:\myfolder\profileinfo.txt”

Configure openvpn client

Unzip the profile downloaded from virtual network point to site configuration. Next, open the vpnconfig.ovpn configuration file from the OpenVPN folder using Notepad. Open profileinfo.txt in Notepad and copy and paste in vpnconfig.ovpn the sections :

# P2S client certificate
# please fill this field with a PEM formatted cert
<cert>
$CLIENTCERTIFICATE
</cert>
# P2S client root certificate private key
# please fill this field with a PEM formatted key
<key>
$PRIVATEKEY
</key>

IMPORTANT :certificate and kay need to be insert in  openvpncon with  —- begin — and —-end —–