Step by step guide to implement SMS authentication to Cisco ASA 5500 - Clientless SSL VPN and Cisco VPN
1 Summary
This is a complete installation guide for securing the authentication to your Cisco ASA 5500 Clientless SSL VPN and Cisco VPN Client Solutions with the Nordic Edge One Time Password Server, delivering two-factor authentication via SMS to your mobile phone. You will be able to test the product, with your current CISCO ASA 5500 and LDAP user database, without making any changes affecting existing users. The guide will also allow you to perform the installation efficiently, it should not take more than one hour. Nordic Edge One Time Password Server provides several methods to deliver one time passwords, like e-mail, tokens, mobile clients, Pledge, prefetch, Yubikey etc. However, in this guide, only SMS will be configured.
This is a step-by-step guide covering the entire installation from A to Z. It is based on the scenario that you are running your Cisco ASA 5500 against Active Directory, and that you install the One Time Password Server on a Windows Server. The One Time Password Server is platform independent and works with all other LDAP user databases, like eDirectory, Sun One, Open LDAP etc. If you are not running Active Directory or Windows and if you have any questions regarding the slight differences in the installation process, you are most welcome to contact us at support@nordicedge.se and we will take you through the entire process.
Table of Contents
- Table of Contents
- 2 Prerequisites
- 3 Getting started
- 4 Installation
- 5 Configuring the One Time Password Server
- 5.1 Start the OTP Configurator
- Start the OTP Configurator by clicking on the left button – “Configuration”
- 5.2 Configure the One Time Password Server
- 5.3 Configure RADIUS
- 5.4 Configure databases
- 5.5 Configure LDAP Host Settings
- 5.6 Configure the LDAP database settings
- 5.7 Configure search filter
- 5.8 Test LDAP Authentication
- 6 Configure the SSL-VPN client settings.
- 7 Configure Delivery Method
- 8 Restart the One Time Password Server as Windows Service
- 9 Add mobile phone number with Microsoft Management Console
- 10 Configuring Cisco ASA 5500
- 10.1 Start ASA device manager
- 10.2 Browse to Configuration, Remote Access VPN, AAA/Local Users, AAA Server Groups and click Add.
- 10.3 Name Server Group OTPserver, choose protocol RADIUS
- 10.4 Add new radius server to the RADIUS group
- 10.5 Configure Radius Server
- 10.6 Create a ”test” connection profile (in case you want to test this for certain users only).
- 10.6.1 Browse to Configuration/Remote Access/Clientless SSL VPN Access/Connection Profiles and click Add
- 10.6.2 Specify Connection Profile Name
- 10.6.3 Specify AAA Server Group = OTPserver
- 10.6.4 Edit Connection Profile Clientless SSL VPN Settings
- 10.6.5 Add Alias if user should be able to select authentication method by drop-down-list
- 10.6.6 Edit Connection Profile Clientless SSL VPN Settings
- 10.6.7 Add Group URL if user should be able to select authentication by specifying URL
- 10.6.8 If user should be allowed to select authentication method by drop-down-list,
- 10.6.9 select this item.
- 11 Configuring ASA5500 for Cisco VPN Client authentication
- 12 Start testing
- 13 Technical questions
Definitions
In this Step by Step guide the Cisco ASA 5500 is referred as “SSL-VPN Solution”
2 Prerequisites
You will need a server, for example a VMware virtual machine, with Windows Server 2003 or higher installed with Ethernet in bridge mode. The server must have a static ip-address configured and must also be able to reach your DNS-servers, your SSL-VPN solution and Active Directory. Since the software is quite small (315 mb) and easy to remove, you can also use any existing server from your network.
Important information regarding communication
The One Time Password Server is a software that can be installed on any existing server in your network or DMZ.
- The One Time Password Server must be able to communicate (Outbound traffic) with your LDAP or JDBC User Database. Default port for LDAP and Secure LDAP are TCP port 389 / 636.
- The SSL-VPN solution must be able to communicate (Outbound traffic) with the One Time Password Server via Radius, UDP port 1812 or 1645 (Outbound traffic).
- If you want to use the Nordic Edge SMS Gateway, the One Time Password Server must be able to communicate (Outbound traffic) with otp.nordicedge.net and otp.nordicedge.se with HTTPS on TCP port 443.
In the following test-scenario you will need to communicate with RADIUS port 1812 or 1645 and use the Nordic Edge SMS Gateway.
3 Getting started
3.1 Register and download the software
Go to www.nordicedge.net and click “PRODUCTS” and then “Downloads”
Type in your name and contact details to receive the software.
A link will be sent for downloading the software. A 30 days evaluation license will be sent via e-mail when you download the software.
Download the 32 or 64 bit version depending on your platform.
4 Installation
4.1 Start the installation
Start the installation on the server where you want to install the One Time Password Server
Please note that if you are installing on a Windows 2008 Server you need to right click on the otp3install.exe using explorer and select “Run as Administrator”.
Click Next
Click Next
Click Next
Click Next
Click Next
Click Next
Click Install
Click Next
Leave default on Yes and click “Done”
Click Done
5 Configuring the One Time Password Server
5.1 Start the OTP Configurator
Start the OTP Configurator by clicking on the left button – “Configuration”
5.2 Configure the One Time Password Server
On the Server page you can set the length of the one time password and for how long it should be valid. Default is 5 minutes.
You can also set a default country prefix, which means you will not need to set it in the mobile attribute
For more information regarding the optional setting please see One Time Password Server 3 – Administration manual
For now, leave this page as default and go on to the next part – Configure RADIUS.
5.3 Configure RADIUS
Change to the RADIUS tab and configure the RADIUS port you want to use to communicate with your SSL-VPN server. In this example we are using RADIUS port No. 1645.
Click Save config.
5.4 Configure databases
In this setup we are going to use the Microsoft Active Directory LDAP database.
Change to the Databases tab and click on the LDAP Database button.
5.5 Configure LDAP Host Settings
For this configuration we will use the active directory installed on the same server as the One Time Password Server. We will use the internal IP-address (127.0.0.1) as host address.
We will use the standard LDAP port No. 389 to communicate with Active Directory.
Admin DN will be the Administrator user to search for user objects in the Active Directory database. For now this user only need read rights to the user objects attributes but be aware that later you might want to use options like disable accounts or the Pledge Enrollment concept from the Pledge Mobile Client. In this event the Admin DN need write rights to modify the disable account attribute and to store oath-keys into an optional user attribute.
Configure your LDAP host settings and click test. You should now get a messages saying “LDAP connection success”
Next step is to configure the LDAP database settings.
5.6 Configure the LDAP database settings
The BASE DN is the search base from where OTPServer will start looking for user objects.
Click on the button with three dots at the right side of the Base DN field to browse your LDAP Database.
Select an Organization Unit or Organization in Active Directory and click OK.
5.7 Configure search filter
Next step is to configure the search filter for One Time Password to search users via selected object classes and attributes according to the Microsoft Active Directory schema.
Click on the “Sample Button” and choose the filter template for MS Active Directory and click OK twice.
5.8 Test LDAP Authentication
Click on the Test LDAP Authentication button and type in the userid of a user you know exist in the directory.
Type in the password
If configuration is correct you will see the following success message.
6 Configure the SSL-VPN client settings.
Since One Time Password Server is also a RADIUS-server, the Cisco ASA 5500 is considered a client to the One Time Password Server.
Next step is to configure the settings for this client.
In the left pane click on ”Clients”
Choose a name for your Cisco ASA 5500 and enter its ipaddress.
Type in the RADIUS shared secret.
Choose the Active Directory repository you configured earlier as User Database.
Click Save
7 Configure Delivery Method
The Delivery Methods category is meant for enabling and configuring one or more delivery methods that can be used by the OTP Server to send one-time passwords.
One Time Password Server offers various methods like SMS, Oath Tokens, Instant Messaging, HTTP, Yubikey.
In this example we will use SMS with the Nordic Edge SMS-service as the SMS-provider.
During the evaluating phase we offer customers to use our Nordic Edge SMS-service free of charge for 30 days from the activation of the Demo Account.
In the left Pane, click “Delivery Methods” and then Nordic Edge SMS. In the right pane enable Nordic Edge SMS Gateway.
To Request a demo account click “Request a demo account”.
Click “Yes”
You should get a success message and the Username and Password for the Nordic Edge SMS-gateway has automatically been filled in. Click OK and Save Config.
8 Restart the One Time Password Server as Windows Service
In the server panel for click “Shutdown”
In Windows Control Panel, open Administrative Tools / Services
Find the NordicEdge OTPServer Service, right click on that service and click “Start”.
9 Add mobile phone number with Microsoft Management Console
Add a mobile phone number to your test user mobile phone attribute by starting the Microsoft MMC, select the test user and enter the mobile phone number into the Mobile attribute.
10 Configuring Cisco ASA 5500
10.1 Start ASA device manager
10.2 Browse to Configuration, Remote Access VPN, AAA/Local Users, AAA Server Groups and click Add.
10.3 Name Server Group OTPserver, choose protocol RADIUS
10.5 Configure Radius Server
Configure Radius Server : Interface name, IP address to OTPserver and the pre-shared key (shared secret) between the One Time Password server and Cisco ASA5500.
Ensure you use the same radius ports in both OTPserver ASA5500.
You have now configured a group ”OTPserver” and defined a Radius Server in this group.
This group can now be used as an authentication method.
10.6 Create a ”test” connection profile (in case you want to test this for certain users only).
10.6.1 Browse to Configuration/Remote Access/Clientless SSL VPN Access/Connection Profiles and click Add
10.6.2 Specify Connection Profile Name
10.6.3 Specify AAA Server Group = OTPserver
10.6.4 Edit Connection Profile Clientless SSL VPN Settings
10.6.5 Add Alias if user should be able to select authentication method by drop-down-list
10.6.6 Edit Connection Profile Clientless SSL VPN Settings
10.6.7 Add Group URL if user should be able to select authentication by specifying URL
10.6.8 If user should be allowed to select authentication method by drop-down-list,
10.6.9 select this item.
Login successful, the user will now get to his portal, which can
be customized depending on Active Directory membership, PC health status
( antivirus , hotfix etc ) and authentication method
11 Configuring ASA5500 for Cisco VPN Client authentication
11.1 Add a new ( or Edit an existing) Cisco VPN Client Connection Profile to use the OTPserver
11.2 At the Cisco VPN Client, create an entry with correct name and password
· Name must match the connection profile name at previous slide.
· Password must match the pre-shared key in ASA5500.
(Note : This can be distributed via MSI installation)
If you want to purchase the product, you are more than welcome to contact us at e-mail sales: sales@nordicedge.se. phone: +46 8 122 07 500 fax: +46 8 122 07 508.
13 Technical questions
If you have any technical questions, please contact us at support@nordicedge.se
Thank you for showing interest in our product!
The Nordic Edge One Time Password Server Team
