How to safely connect to Skype for Business using RSA security token

SkypeShield offers innovative security solution that allows users of RSA SecurityID and other secure tokens to safely connect to their organization’s Skype for Business server without using their  Active Directory (AD) credentials.

SkypeShield’s solution adds another secured authentication option, enabling strong mobile and external Skype for Business authentication for organizations with a network policy that requires Hardware One Time Password (OTP) or Two Factor Authentication (TFA).

Skype for Business RSA Token Authentication

Organizations that use OTP tokens, such as RSA SecurID Authenticator device, have a problem using them in conjunction with Skype for Business. The new solution enables therefore both mobile and desktop users to connect to Skype for Business using their RSA token while avoiding the usage of AD credentials and implementing TFA.

Moreover, SkypeShield can require the user to register in a self-service portal to further add security to the authentication process and make sure only registered devices can connect.

The device registration process is completed once and the user uses his RSA token to authenticate and enable Skype for Business connectivity thereafter.

“The market for security tokens is constantly growing, requiring organizations, that use Skype for Business to look for new security solutions,” said Guy Eldan, CEO of AGAT Software which developed SkypeShield. “After we launched a special solution for smart card mobile authentication, it was only natural to add another special solution for security tokens.”

SkypeShield’s solution does not require setting Active Directory Federation Services (ADFS) and offers a complete user experience including both Skype for Business & Exchange information, which can be safely used from the external device.

It also addresses account lockout protection and other TFA software solutions for external Skype for Business clients.

A recent survey by research company Frost & Sullivan indicated that the global OTP market is growing at an annual rate of 7.5 percent and is expected to reach $1.2 billion by 2017.

Protecting EWS while publishing Skype for Business

Using Skype for Business (Lync), the client interacts with the Exchange server to obtain meeting information. In order to implement this connection, the deployment of Skype for Business requires Exchange Web Services (EWS) published externally to the world.

This exposes the client to several threats:

  • The deployment of EWS includes an authentication service, thus exposing the network to account lockout in case of a DDoS attack.
  • The EWS service allows for retrieving events, mails and attachments, tasks and contacts. Therefore, once exposed, all the Exchange data is also exposed.
EWS Protector

So, for example, users using Outlook Web Access (OWA) have access to their full mail data, creating the risk that an attacker with valid AD credentials will also obtain access to the users’ organizations’ mail by using this services.

To minimize this risk, SkypeShield blocks any request for information that arrives from a device that is not registered, and adds a Two Factor Authentication (TFA) layer for the Exchange.

SkypeShield is based on a Two Factor Authentication using the client’s password and device. Thus, unauthorized use of the user’s credentials will not be sufficient to connect to Lync or Exchange without having access to the device itself. This also allows for restricting the usage of these services to approved or registered devices only.