"Many organizations' employees and contractors use enterprise telework technologies to perform work from external locations. Most teleworkers use remote access technologies to interface with an organization's non-public computing resources. The nature of telework and remote access technologies-permitting access to protected resources from external networks and often external hosts as well-generally places them at higher risk than similar technologies only accessed from inside the organization, as well as increasing the risk to the internal resources made available to teleworkers through remote access. All the components of telework and remote access solutions, including client devices, remote access servers, and internal resources accessed through remote access, should be secured against expected threats, as identified through threat models. Major security concerns include the lack of physical security controls, the use of unsecured networks, the connection of infected devices to internal networks, and the availability of internal resources to external hosts. This publication provides information on security considerations for several types of remote access solutions, and it makes recommendations for securing a variety of telework and remote access technologies. It also gives advice on creating telework security policies."
NIST Special Publication 800-46, Revision 1
National Institute of Standards and Technology: http://www.nist.gov/