SecSign ID Plugin: Windows Services

The SecSign ID Credential Provider is not active if Windows is booted into Safe Mode. That means it has to made sure that users cannot reboot Windows into Safe Mode.

Microsoft’s Remote Desktop Web Access service allows to run published Windows applications from a browser. If the SecSign ID log-in has been added to the RD Web Access site then after the usual log-in with Windows user name and password a second page asks for confirmation of the log- in using SecSign ID:

MS Remote Desktop Web Access: Installation

Log-in using a domain administrator account an the Windows Server which has the RD Web Access role. Then run SecSign-RD-WebAccess-Setup.exe:

Run cmd.exe or a PowerShell

• Type: certlm.msc
• Select the node Certificates – Local Computer -> Personal -> Certificates.
• Select the HTTPS certificate of this host.
• Select All Tasks -> Manage Private Keys… from the context menu of the certificate.
• Add Read permissions for the SERVICE account.
• The integration of SecSign ID into the Microsoft Remote Desktop Web Access log-in requires to edit five files in C:\Windows\Web\RDWeb. This installer has placed an example of each file with the required modifications into this folder and its subfolders. The example files have the same file name plus the extension SecSignID.
• Run a diff tool like ExamDiff or Araxis Merge.
• Integrate the modifications from the example files having .SecSignID as extension into the original files on your machine. Be careful since your files may have other modifications already which you probably want to keep. For example you may have modified the files in the past to present the RD Web Access site in your corporate design.
• If you are unsure how to do the modifications we will be happy to perform the modifications for you. In this case please send us a copy of the respective files or the whole RDWeb folder to support@secsign.com.
• Run regedit.exe.
• Open HKEY_LOCAL_MACHINE\SOFTWARE\SecSign\RDWebAccess.
• Set SecSignIDServerHostName and SecSignIDServerPort to the host name and port of your SecSign ID Server. You will find the port number in the properties files of your SecSign ID Server in the line secsignidserver.port=… .
• If you have a second SecSign ID Server enter its host name and address in FallbackSecSignIDServerHostName and FallbackSecSignIDServerPort. Otherwise, you may enter the values of the primary SecSign ID Server again.
• The values configured in ServiceAddressForSecSignApp and ServiceNameForSecSignApp will be displayed in the user’s SecSign App during a log-in.
• SharedSecretWithRDGateway shall contain any random bytes. Please type any arbitrary characters here but make sure that the length remains 64 bytes.

After installing the SecSign ID plug-in for Microsoft Remote Desktop Gateway the shared secret has to be copied there. The SecSign ID RD Web Access plug-in uses the secret to sign a gateway access token which it inserts into the RDP files of each published application. The SecSign ID RD Gateway plug-in will validate the signature using the same secret.

Finally, open your RD Web Access URL in a browser, log-in using your Windows user name and password and test the SecSign ID log-in. If anything fails the Windows Event Log will contain more information in Windows Logs → Application with the source SecSign ID RD Web Access.

The SecSign ID log-in integration into RD Web Access alone only protects the RD Web Access log-in in a browser. A user who knows the necessary details to create an RDP file could log-in directly at the RD Gateway using the Remote Desktop Client. Furthermore, users could download RDP files generated by RD Web Access and use them again later without logging in at the RD Web Access site again.

The SecSign ID PAA (pluggable authentication and authorization) plug-in for Microsoft’s Remote Desktop Gateway prevents the aforementioned unwanted direct log-ins at the RD Gateway. To achieve this, the SecSign ID plug-in validates the signature of the gateway access token which has been inserted into the RDP file by the SecSign ID RD Web Access plug-in after a successful SecSign ID log-in at the RD Web Access site using a browser.

• Log-in using a domain administrator account an the Windows Server which has the RD Gateway role.
• Run SecSign-RD-Gateway-Setup.
• Run regedit.exe.
• Open HKEY_LOCAL_MACHINE\SOFTWARE\SecSign\RDGatewayAuthentication.
• SharedSecretWithRDWebAccess has to contain exactly the same 64 bytes as the respective
  value SharedSecretWithRDGateway in the adjacent registry key RDWebAccess.
• AccessTokenMaxAgeSeconds defines for how many seconds after a RD Web Access log-in the generated RDP files are allowed to run the published applications. The remote desktop client’s connection to the RD session host remains open for a certain time. During this time the opening of published applications is still possible even if AccessTokenMaxAgeSeconds has expired already. A user may always generate fresh RDP files by reloading the RD Web Access page in his browser. Only someone you downloads and copies an RDP file cannot use it after the RD Web Access log-out or on another computer when AccessTokenMaxAgeSeconds has expired.

The Windows Event Log will contain information about SecSign ID log-ins in „Windows Logs → Application“ with the source „SecSign ID RD Gateway“.

The SecSign ID RADIUS proxy allows to add the SecSign ID log-in to systems with RADIUS support. This includes for example a VPN log-in to a Windows Server 2012. A RADIUS client who wants to process the log-in of a user will send a request to the SecSign ID RADIUS proxy. The proxy will forward the primary authentication containing information about user name and password to a forward RADIUS server. If this server has validated user name and password and allows the log-in the proxy will initiate a SecSign ID log-in as a secondary authentication. The user then authenticates the log-in using his private 2048 bit key in the SecSignApp on his smart phone. Finally, the SecSign ID RADIUS proxy will inform the RADIUS client about the success of the log-in.

Radius Proxy: Installation

Java VM

As the SecSign ID RADIUS proxy is written in Java it can be run on any operating system with Java support like for example Windows or Linux. So the first step of the installation is to install a recent Java virtual machine preferable with 64 bit available at Oracle’s web site.

SecSign ID RADIUS proxy installation

The directory SecSignIDRadiusProxy contains the application code in a JAR file and its configuration file. This directory has to be copied to the system that shall run the SecSign ID RADIUS proxy.

SecSign ID RADIUS proxy configuration file

The configuration file secradiusproxy.properties needs to be edited:
The default port number of RADIUS is 1812. If necessary, if different value may be set here:

If the SecSign ID RADIUS proxy shall only bind to a specific IP address it may be specified here. The default is to bind to all IP addresses the machine has.

For each RADIUS client (for example a Microsoft Windows Server) the proxy needs to know the IP address and the shared secret. The list of RADIUS clients starts with the index ‘0’ and may have any number of entries which are consecutitvely numbered.

The proxy also needs to know where to forward the RADIUS access requests for validation of the primary authentication credentials (user name and password). This forward RADIUS server may be for example another Microsoft Windows Server or even the same as the RADIUS client.

For each Windows user whose log-in shall be secured be the SecSign ID the Active Directory must contain an attribute containing the SecSign ID user name of this user. The proxy uses an LDAP connection to query the SecSign ID user name in the Active Directory. For this LDAP connection it needs the name and password of a technical user with read access to the users branch of the Active Directory. Furthermore, the base DN will tell the proxy where to find the users branch in the LDAP tree. The recommended full name of this technical user is SecSign ID Radius Proxy and its descrption: Technical user to allow AD LDAP queries for the SecSign ID RADIUS proxy.

The proxy will keep a copy of each received RADIUS packet for a certain time in order to recognize duplicate packets. The proxy will also remember the Windows user names for whom it is waiting for the completion of the SecSign ID log-in. The proxy will not start a new log-in session for such users if requested by the RADIUS client. The time out for both list entries can be specified here.

In order to initiate a SecSign ID log-in the SecSign ID RADIUS proxy needs the host name of the SecSign ID server and optionally of fallback SecSign ID servers:

The connection to the SecSign ID server is TLS encrypted. Therefore, a DER encoded trusted certificate of the SecSign ID server may be configured. If the server uses a certificate issued on its official DNS name by a regular trustcenter this configuration entry is not necessary.

A timeout value be set after which the proxy tries to send its request to the next fallback SecSign ID server:

The SecSign ID RADIUS proxy may use a HTTP proxy to send requests to the SecSign ID server. The HTTP proxy has the following settings:

If certain hosts can be reached without the general HTTP proxy they can be named here:

The SecSign ID RADIUS proxy may write a log file. It contains all messages whose severity is equal to or above a specified level.

The levels are:

• 0: Error
• 10: Warning
• 20: Standard
• 30: Usage
• 40: Event
• 50: Debug
• 60: Verbose

The proxy may begin a new log file each day:

Radius Proxy: Start

The proxy can be started with:

The proxy will output messages like:

Pressing ^C in the terminal window will end the proxy.

Radius Proxy: Windows Server 2012 R2 as Radius Client

The SecSign ID RADIUS proxy can be used with different systems that support RADIUS. As an example the following section shows how to configure the SecSign ID RADIUS proxy in a Microsoft Windows Server 2012.

In the Server Manager the option Network Policy Server in the Tools menu will open the configuration of the Network Policy Server. A new RADIUS server can be added at the node NPS (Local) – RADIUS Clients and Servers – Remote RADIUS Server Groups. There, in the context menu the option New opens the following dialog in which a RADIUS server group with a name like SecSign ID RADIUS proxy group may be created:

The button Add shows a dialog in which the IP address or host name of the SecSign ID RADIUS proxy can be added:

The shared secret has to be entered in the Authentication/Accounting tab. It must be identical to the value of secradiusproxy.radiusclient..sharedsecret in the configuration file of the proxy.

In the Load Balancing tab it is necessary to set the Number of seconds without response before a request is considered dropped to at least 60 seconds. This time allows the user to perform the SecSign ID authentication on his smart phone. The SecSign ID RADIUS proxy cannot answer the RADIUS client before the SecSign ID log-in is completed.

Now, the Microsoft Network Policy Server will be configured to send RADIUS requests to the SecSign ID RADIUS proxy in case of for example a VPN log-in: Selecting the node NPS (Local) – Policies – Connection Request Policies shows the following dialog:

A double click on Microsoft Routing and Remote Access Service Policy displays a dialog in which the tab Settings has to be selected. The node Forwarding Connection Request – Authentication allows to determine that RADIUS requests shall be forwarded to the SecSign ID RADIUS proxy: