Skip to main content

Network Endpoint Assessment

Document Charter Network Endpoint Assessment WG (nea)
Title Network Endpoint Assessment
Last updated 2006-10-16
State Approved
WG State Concluded
IESG Responsible AD Stephen Farrell
Charter edit AD (None)
Send notices to (None)

Network Endpoint Assessment (NEA) architectures have been implemented
   in the industry to assess the "posture" of endpoint devices for the
   purposes of monitoring compliance to an organization's posture policy
   and optionally restricting access until the endpoint has been updated
   to satisfy the posture requirements. An endpoint that does not comply
   with posture policy may be vulnerable to a number of known threats that
   may exist on the network. The intent of NEA is to facilitate corrective
   actions to address these known vulnerabilities before a host is exposed
   to potential attack. Note that an endpoint that is deemed compliant may
   still be vulnerable to threats that may exist on the network. The
   network may thus continue to be exposed to such threats as well as the
   range of other threats not addressed by maintaining endpoint
   Posture refers to the hardware or software configuration of an endpoint
   as it pertains to an organization's security policy. Posture may
   include knowledge that software installed to protect the machine (e.g.
   patch management software, anti-virus software, host firewall software,
   host intrusion protection software or any custom software) is enabled
   and up-to-date. An endpoint supporting NEA protocols can be queried for
   posture information.
   An organization may make a range of policy decisions based on the
   posture of an endpoint. NEA is not intended to be prescriptive in this
   regard. Supported deployment scenarios will include, but are not
   limited to, providing normal access regardless of compliance result
   along with any recommendations for remediation ("advisory mode"), as
   well as providing restricted access sufficient for remediation purposes
   and any essential services until an endpoint is in compliance
   ("mandatory mode"). Specifying mechanisms for providing restricted
   access is outside the scope of the NEA WG.
   Since NEA involves many different components from different vendors,
   interoperability is important. The NEA working group will
   develop standard protocols at the following three  layers in the
   the Posture Attribute protocol (PA),  the Posture Broker protocol
   (PB), and the Posture Transport protocol (PT). PA and PB will be
  designed to
   support a variety of PT protocols. Together,  PA, PB and the mandatory to
   implement PT protocols will allow interoperability between an NEA Client
   from one vendor and an NEA Server from another.
   Since there are already several non-standard protocols at these
   layers, the NEA working group will consider these existing protocols as
   candidates for the standard protocols. A requirements document will be
   written and used as a basis for evaluating the candidate protocols. The
   working group may decide to standardize one of the candidate protocols,
   use one of them as a basis for a new or revised protocol, or decide
   that a new protocol is needed.
   The NEA Requirements document will include a problem statement,
   definition of terms, requirements for the PA and PB protocols, and an
   overall security analysis. It will also include generic requirements
   for the protocol transporting PA, PB: the Posture Transport protocol
   The PA (Posture Attribute) protocol consists of posture attributes that
   are carried between a particular Posture Collector in a NEA client and
   a particular Posture Validator in a NEA Server. The PA protocol is
   carried inside the PB protocol. A base set of standard posture
   attributes will be specified that are expected to address many common
   posture policies. Vendor-specific attributes will also be supported;
   vendor-specific attributes will be identified by a private enterprise
   number and a vendor assigned value. Vendors are strongly encouraged to
   document vendor-specific attributes in an RFC. The NEA WG will
   investigate the use of a standard syntax for all attributes.
   The PB (Posture Broker) protocol aggregates posture attributes from one
   or more Posture Collectors in an NEA client and sends them to the NEA
   server for assessment by one or more Posture Validators.
   The PT (Posture Transport) protocol carries the PB protocol. The
   is that the PT protocol is a shim protocol that defines an
  encapsulation of PB
   within an existing standard transport protocol. Existing standard transport
   protocols will be leveraged to the extent possible. The NEA WG may specify
   more than one PT to meet the requirements of different deployment
   The NEA WG will specify at least one mandatory to implement PT protocol.
   PT protocol specifications must describe any limitations
   that they impose on PB and PA (e.g. half duplex).
   One commonly discussed issue with NEA systems is how to handle
   compromised endpoints, whose reports of their own posture may not be
   accurate. Detecting or handling such endpoints is out of scope of the
   NEA WG. Work on PA will focus on attributes useful for assessing
   posture of those endpoints reporting accurate information. However, the
   protocols developed by the NEA WG must be designed to accommodate
   emerging technologies for identifying and dealing with lying endpoints.
   Note that NEA is not chartered to develop standard protocols for
   remediation. NEA is intended to be used with new or existing tools that
   can be used in the absence of NEA. NEA is applicable to computing
   enterprise environments, where endpoints accessing the enterprise's
   network are owned and/or expected to conform to the policies set forth
   by the organization that owns and operates the network. All other
   cases are outside the scope of the NEA charter, since we do not know
   that NEA would be useful in such cases. NEA applicability and security
   considerations will be described in the appropriate NEA documents.
   Further work in the NEA WG will be considered via the rechartering
   process after the completion of these milestones.