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Using Freeradius

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Alexander Ryzhov edited this page Nov 20, 2015 · 1 revision

Introduction

In this tutorial we're going to install freeradius2 (EAP-TTLS, PAP). Why should I consider using WPA2-enterprise on my router ?

  1. Eliminates the security risks of PSK passwords
  2. Puts a damper on snooping
  3. Enables enhanced security methods
  4. Entware's freeradius version works great on asus mips routers
  5. Get the best wireless security possible on your premium router

We have several authentication methods to choose from like EAP-TLS, EAP-PEAP, ... I personally think EAP-TTLS is one of the better options because it is not required to install client certs but still uses a secure tunnel (server certificates) before inner client authentication is taking place. Here are some more detailed descriptions:

The only disadvantage with EAP-TTLS is that there's no native support for it in Windows 7 and earlier but there's still an free third party solution for pc not sure about windows phone 8 if you cannot upgrade to 8.1.

Instead of using RSA keys, I have used elliptic curve keys and this does work extremly well on freeradius and clients.

Prerequisites

Router with RADIUS authentication support.

Installation

Install required packages^

opkg install freeradius2 \
freeradius2-common \
freeradius2-mod-eap \
freeradius2-mod-eap-tls \
freeradius2-mod-eap-ttls \
freeradius2-mod-files \
freeradius2-mod-pap

Configuration

I have created a very stripped version of the needed config files & missing one after testing. For making things a bit easier we're gonna use that one.

cd /opt/etc/ && cp -r freeradius2 freeradius2.bak
cd freeradius2 && rm -rf *
opkg install wget
/opt/bin/wget --no-check-certificate -O - http://goo.gl/Ykov6H | tar -xzC /opt/etc/freeradius2

Generating certs

cd /opt/etc/freeradius2/certs
/opt/bin/wget --no-check-certificate http://goo.gl/kNg6Ms -O openssl.cnf
mkdir -p CA/private new export

Generate private key

openssl ecparam -name secp521r1 -genkey -noout | openssl ec -aes256 -out CA/private/ec-cakey.pem

Generate self-signed X.509 CA certificate

When generating the CA Certificate Request do not leave fields blank, we can use that as an extra check of the validity of the certificate. Example of mine: C=BE, ST=Limburg, L=Hoeselt, O=Last-Name, OU=IT Department, CN=Certificate Authority Last-Name

openssl req -new -x509 -out CA/ec-cacert.pem -outform PEM -SHA512 -key CA/private/ec-cakey.pem \
 -keyform PEM  -days 3650 -extensions v3_ca -config ./openssl.cnf

Export .pem to .der

This is needed to import the certificate on Windows machines. You can skip this step as it's also possible to import certificates in .p12 format in Windows and we need this .p12 format to install certicates on your android, iOS devices.

openssl x509 -outform DER -in CA/ec-cacert.pem -out export/ec-cacert.der

Export .pem to .p12

This format works on Android, iOs and Windows. You will be asked for the private key password earlier and to create an export password. You need the export password when installing the certificate on your phone. Change "Name of Your Certicate" below to a "friendly name you want to assign to the certificate".

openssl pkcs12 -export -in CA/ec-cacert.pem -inkey CA/private/ec-cakey.pem \
 -out export/ec-cacert.p12 -name "Name of Your Certificate" -cacerts

Generate private server key & server certificate request

When generating server certificate request do not enter an challenge password & optional company name Example of mine: C=BE, ST=Limburg, L=Hoeselt, O=Last-Name, OU=IT Department, CN=Server

openssl req -nodes -SHA512 -newkey ec:CA/ec-cacert.pem -new -days 3650 \ 
-out new/ec-server_req.pem -keyout new/ec-server_key.pem -config ./openssl.cnf

Encrypt private server key

mv new/ec-server_key.pem new/ec-server_key_temp.pem && openssl ec \ 
-in new/ec-server_key_temp.pem -aes256 -out new/ec-server_key.pem && \
rm -rf new/ec-server_key_temp.pem

Generate signed X.509 server certificate

openssl x509 -req -extfile openssl.cnf -out new/ec-server_cert.pem -SHA512 \
 -CA CA/ec-cacert.pem -CAkey CA/private/ec-cakey.pem -in new/ec-server_req.pem \
 -days 3650 -set_serial 0x01

Move ec-server_cert.pem ec-server_key.pem to certs directory and remove new directory

mv new/ec-server_cert.pem  new/ec-server_key.pem ./ && rm -rf new
chmod 0400 ec-server_cert.pem && chmod 0400 ec-server_key.pem

Remove openssl.cnf

rm openssl.cnf

Generate Diffie Hellman (takes some time)

openssl dhparam -check -text -2 2048 -out dh 
chmod 0600 dh

Move CA & export dirs on to a secure storage place

You will need a samba share or scp or winscp to copy them to your pc. You will need:

  • ec-cacert.pem on Linux as CA certificate
  • ec-cacert.der or .p12 on Windows as CA certificate
  • ec-cacert.p12 on Android as CA certificate

Now you should only have ec-server_cert.pem, ec-server_key.pem and dh in your certs directory.

Edit eap.conf (/opt/etc/freeradius2/eap.conf)

cd /opt/etc/freeradius2 && vi eap.conf

Change private key pass to the password you have used to encrypt the ec-server_key.pem

Open an other terminal

Go to the certs directory. Check issuer of the server certificate & replace this DN with the one at check_cert_issuer

cd /opt/etc/freeradius2/certs
openssl x509 -noout -in ec-server_cert.pem -issuer

Edit clients.conf (/opt/etc/freeradius2/clients.conf)

  • Change network range, netmask at client line. I'm assuming that the IP-address of the router = 192.168.1.1. If this is not the case change it : here and in /opt/etc/freeradius2/radiusd.conf & /opt/etc/freeradius2/sites/inner-tunnel.
  • For the secret key of the access point I recommended a 32 chars key. It is possible to use longer keys then 32 chars but I found out that the WiFi became slower. (copy this to a text editor for later if you're already using on a wired device). Use a site like this one to generate the key and do not use strange punctuations, etc ... I'm not sure which one are allowed and which one not.

Edit users file (/opt/etc/freeradius2/users)

Change the login name and password to the one you are going to use. You also can add, change attributes like session-timeout to a more appropriate value for you.

Edit radiusd.conf (/opt/etc/freeradius2/radiusd.conf)

We are going to change the max request value dependent on the number of wireless clients that are going to connect with our radius server.

max_requests: The maximum number of requests which the server keeps track of. This should be 256 multiplied by the number of clients. e.g. With 4 clients, this number should be 1024.

Starting Freeradius2

Let's run a test to check if the server initialized correctly

radiusd -XX

If the server is listening for requests you're good to otherwise check error(s). Create pid directory & start the server.

mkdir /opt/var/run/radius
/opt/etc/init.d/S55radiusd start

Configure router wireless settings for WPA2-Enterprise

Use the wired device now if you are not using it and login to the routers webinterface and go to the wireless page, change authentication method to WPA2 enterprise for 2.4Ghz and 5Ghz if you use that band also.

Go to the "Radius Setting" tab and change the IP-address of the radius server to the IP-address of your router. Change port to 1812 Enter the secret from the clients.conf which we still have open in a texteditor or open clients.conf in a telnet, ssh session to copy, paste it. Do the same thing for the other band if you are using it. At this moment server should be running successfully and being able to receive authentication request.

Configuring wireless clients

On Windows 7, 8 we need first to import the ec-cacert.der or ec-cacert.p12. Place ec-cacert.(der-p12) on a USB stick or something portable that you could copy the cert over to the wireless clients.

1. Open mmc as administrator -> File Add/Remove snap-in -> certificates -> add 
   -> computer account -> local computer -> finish -> ok 
2. Open certificates, Open Trusted Root Certification Authorities.
3. Right click on certificates -> all task -> import -> next -> browse to ec-cacert.der , ...
4. Close console1 do not save settings.

Windows 8 users can skip next step. For Windows 7 there's an old alternative called SecureW2 which was free until version 1.13. But there's even a better alternative which does works correctly with ec keys. It's eap-ttls software especially for intel wireless cards but it does also works for broadcom devices. Assuming all of you Windows 7 users also have an "intel" card here's the driver link.

Windows 7

Select PAP
Username xxx
Domain leave blank
Password xxx
Roaming identity anonymous

Check Validate Server Certificate
	-Certificate Issuer (Select your certificate)

Check Specify Server or Certificate Name
	-Server name must match the specified entry exactly (Your server CN)

Windows 8 Configure EAP-TTLS

Android Devices

For android place the .p12 file on your sdcard.
On my phone 4.1.1, to install a certificate go to security -> install from storage.
You will be asked for the export password enter it if you have and install the certificate.
When connecting to the network choose EAP-TTLS as eap-method	
Choose PAP as Phase 2 verification
Identity xxx 
Password xxx
Enable advanced options
CA certificate the one you installed
Anonymous identity just enter anonymous.
That's it you should be able to connect successfully.

iOS Devices

Links

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