Concluded WG IP Security Remote Access (ipsra)
Note: The data for concluded WGs is occasionally incorrect.
|IP Security Remote Access
|Security Area (sec)
|Paul E. Hoffman, Sara Bitan
Final Charter for Working Group
The work of the IPSec working group is almost concluded at the time
this charter is being written. The IPSEC working group has produced
three proposed-standard protocols: AH, ESP, and IKE.
When the IPSec WG considered requirements for the protocols it
produced, inadequate attention was given to the support for so-called
"road warriors"-- remote users that use personal portable computing
devices, or who use Internet "kiosks" to access private networks on the
other side of an IPSEC gateway. Such users will typically connect to
the Internet at a point most convenient to them at the time of
o Dial-in to a local ISP
o Wireless or wired LAN access at a conference, hotel or airport
There are some fundamental differences, that are relevant to IPSec
usage, between these remote access scenarios and scenarios where both
parties reside in fixed locations:
The authenticated entity must be a human user, i.e. human
interaction is required during the authentication process.
In each session the remote access entity interacts with at least two
access points- the Internet access point and the organization entry
point. The authentication must be established between the remote
access entity and the entry point to its organization (and not into
The remote access entity wishes to connect to its organization's
distributed network. This network might be large and complex and
with multiple remote access entry points. Although the user
physical location is not changing during the remote access session,
he might use different entry points during the same session.
In the above scenario, the entry points don't have information on
all the entities that are allowed to access the network. When the
remote access begins the entry point should obtain information on
the remote access entity that will enable it to grant secure access
to the network. This information might be credentials supplied by
the remote access entity itself, or information supplied by some
Several human users can share the same physical machine.
The remote access entity doesn't have its configuration information.
This information must be transported securely to the remote access
implementation after the entity's identity has been authenticated.
There are systems that rely on different identities for access
control - examples are IP address, users names and others. Most of
the time the user's remote access implementation won't have this
information available to it before the connection begins.
Organizations will not change their access control systems. Hence
this information must be conveyed securely to the remote access's
implementation after the authentication.
IKE supports four authentication methods; one method is based on pre-
shared secrets, while the other three are all public-key variants, with
various desirable properties. The use of pre-shared secrets scales
very badly, requiring O(N**2) keys to be managed to provide effective
security. The authentication methods based on public-key technology
assume, to a certain extent, that the organization involved has
deployed its own public-key infrastructure for authentication of
individual human users. This assumption is taking much longer to reach
fruition than one would hope.
Most organizations have legacy authentication systems that are adequate
for providing authentication of individual human users (OTP,
username/password, hardware authentication tokens, etc). Most
organizations insist on the ability to continue to to support such
legacy authentication mechanisms as they deploy an IPSEC infrastructure
at the perimeter of their networks.
The goals of this working group are:
to define a remote access architecture. The entities participating
in the remote access and their relationships will be defined in a
framework document. This document will be published as an
to define a standard mechanism to accomplish human user
authentication to an IPSec device running IKE, using legacy
authentication mechanisms. One of the goals of introducing this
mechanism is to allow for an easy migration path to PKI. The
mechanism will be published as a standards-track protocol document.
to define a standard mechanism to convey user configuration
information from user's own private network to its local IPSec
implementation. This mechanism will be published as a
to provide a standard mechanism to convey user information required
for access control from the user's own private network to its local
IPSec implementation, while answering the special requirements of
remote access users. This mechanism will be published as a
track protocol document.
to work closely with the MOBILEIP Working Group so that the
respective protocols work together.
The WG strongly prefers mechanisms that require no changes to AH, ESP
or IKE protocols. If such changes are deemed necessary, the IPSec WG is
contracted to carry out such changes. Pursuing this approach is most
likely to produce mechanisms that are easy to implement and deploy.
|User access control mechanism submitted for standard track
|User configuration mechanism submitted for standard track
|User authentication to IKE mechanism submitted for standard track
|Remote access framework submitted for standards track
|Requirements document submitted for Informational
|First WG meeting
|Submit Internet-Drafts of requirements and framework documents