Last Call Review of draft-ietf-httpbis-auth-info-04
review-ietf-httpbis-auth-info-04-secdir-lc-meadows-2015-04-09-00

I have reviewed this document as part of the security directorate's

ongoing effort to review all IETF documents being processed by the

IESG.  These comments were written primarily for the benefit of the

security area directors.  Document editors and WG chairs should treat

these comments just like any other last call comments.

This draft defines the “Authentication-Info” and “Proxy-Authentication-Info”
response header fields for use in HTTP authentication.

These are used for schemes that need to return information once a client’s
authentication credentials have been accepted.

The document defines the syntax, and gives instructions on how it should be
treated (e.g. proxies forwarding a response are

not allowed to modify it).  The actual semantics of the fields depend upon the
protocols that use them.

In the Security Considerations section, the authors note that adding
information to HTTP responses sent across an unencrypted

channel can affect security and privacy.  Indeed the presence of these header
fields alone indicate that HTTP authentication is in use.  Additional
information

could be exposed depending on the authentication scheme; but this is something
that will need to be addressed in the definition of the schemes.

I only have one small question about the Security Considerations section:
wouldn’t there be other headers that indicate authentication is being used, such

as a header indicating that a message contains the client’s credentials?  If
so, I don’t see how the introduction of an additional header field adds any
further risk.

I believe that this ID is ready with nits.

Cathy



Catherine Meadows

Naval Research Laboratory

Code 5543

4555 Overlook Ave., S.W.

Washington DC, 20375

phone: 202-767-3490

fax: 202-404-7942

email:

catherine.meadows at nrl.navy.mil