The basics of teleworker security apply to any type of design and center on protecting the teleworker PC first and then its communications to the central network.
The list of protections recommended for user systems from Chapter 13, "Edge Security Design," and Chapter 14, "Campus Security Design," all apply here; in addition, there are some security precautions that should be considered more essential than they might be in internal-only hosts. Here is the list of considerations for host PCs in teleworker environments:
Under normal circumstances, the chances of an attacker gaining access to communications between two parties on the Internet is so small that it can almost be considered impossible. For example, your credit card numbers are in much more danger of attack by being stored on many different e-commerce sites than they are when sent from your PC to the server. Trying to access data in transit is like trying to photograph a running jaguar. It is much easier to wait for it to stop (though the results are less exciting).
All this changes, however, when the attacker is able to connect to the same network from which the traffic originates. This is exactly the case in airports, coffee shops, hotels, and other public broadband networks. Layer 2 (L2) attacks (discussed in Chapter 6, "General Design Considerations"), among others, create the opportunity for an attacker to gain access to the flow of data before it enters the labyrinth of connections that makes up the Internet. As a result, in addition to protecting the host connected to the network, some cryptographically secure mechanism should be used to protect the data in transit. For most organizations, this means IPsec VPNs as discussed in Chapter 10. For others, it can mean limited access through session layer crypto such as SSH or Secure Sockets Layer (SSL)/Transport Layer Security (TLS). In the designs that follow, this crypto can originate from the PC directly (in the case of the software design) or from a hardware VPN device (in the hardware design).