RE: X#NodeArchitecture draft - next steps

David,

Sites might be small. If a given target code has a known weakness just not 
answering or even answering "not understood" invites an attack by a 
scanner.
IMHO the best solution would be for the draft to say nothing.

Julo



[email protected] 
07/04/06 23:24

To
Julian Satran/Haifa/IBM@IBMIL
cc
[email protected], [email protected]
Subject
RE: [Ips] X#NodeArchitecture draft - next steps






IMHO, a site-wide policy of not using the key is within reason.
Obfuscating the value defeats the primary purpose of the key -
the interest is in what is *actually* running, not the name
of some other implementation that this one ought to be
behaviorally indistinguishable from.  Not sending the key is
a better means of dealing with this concern.
 
Thanks,
--David

From: Julian Satran [mailto:[email protected]] 
Sent: Friday, April 07, 2006 8:40 AM
To: Black, David
Cc: Black, David; [email protected]; [email protected]
Subject: RE: [Ips] X#NodeArchitecture draft - next steps


I am not sure that not sending the key is that good a measure (not sending 
it when it was previously seen is a way of leaking information). 
I guess what you want to mandate is that the value can be specifically 
faked (set) and/or responding "not understood". 

Julo 


[email protected] 
06/04/06 18:08 


To
[email protected] 
cc
[email protected], [email protected] 
Subject
RE: [Ips] X#NodeArchitecture draft - next steps








Dave,

> New proposed text:
> 
> 3.  Security Considerations 
> 
>    In certain environments where security is a primary concern,
>    the use of this extension key may not be appropriate as it
>    reveals specific details about an iSCSI node.  For these
>    environments, nodes implementing this public extension key
>    MUST provide a method to disable sending the key.  In
>    addition to providing a disable mechanism, security sensitive
>    environments SHOULD consider use of IPsec, as specified in 
>    RFC 3720 and 3723, as a means to shield the contents of this
>    key from observers of network traffic.

Good start, needs editing to something like:

   This extension key transmits specific implementation details
   about the node that sends it; such details may be considered
   sensitive in some environments.  For example, if a certain
   software or firmware version is known to contain security
   weaknesses, announcing the presence of that version via this
   key may not be desirable.  The countermeasures for this
   security concern are:
                - not sending the extension key, or
                - using IPsec to provide confidentiality for the iSCSI
                                 connection on  which the key is sent (see 
RFC 3720
                                 and RFC 3723).
   To support the first countermeasure, all implementations of
   this extension key MUST provide an administrative mechanism
   to disable sending the key.

Reasons for the edits:
- Focus on specific threat, not general "where security is a primary
                concern".
- Make the "MUST" for disabling transmission of the key globally
                applicable, vs. possibly scoped to specific environments.
                This is a "MUST implement" requirement, not "MUST use".
- Avoid the "SHOULD ... use ... IPsec" phrasing, at least for now.

> New proposed text:
> 
>    The following described Public Extension Key is sent during
>    the login phase of an iSCSI normal session.  It is important
>    to note that the proper use of this key is to provide enhanced
>    logging and support capabilities, and for better understanding
>    of customer environments.  Functional behavior of the iSCSI
>    node MUST NOT depend on the presence, absence, or content of
>    the key.  The key MUST NOT be used by iSCSI nodes for things
>    such as interoperability, performance, exclusion or deception
>    of other nodes, or other uses not defined here.  To enforce
>    proper use, iSCSI nodes MUST NOT allow user modification of
>    the key value(s), and SHOULD set the value automatically based
>    on standard internal interfaces.

This one is close - 3 suggestions:
- "proper" -> "intended"
- remove "and for better understanding of customer environments" or
                replace it with something more specific like "and to 
enable
                collection of iSCSI implementation usage information"
- The "such as ... or other uses not defined here" is not sufficiently
                precise.
The last one is crucial - it needs to be easy for an implementer to
determine whether s/he's stepped over this line.

I'm comfortable with not mentioning the JavaScript and browser versions
mess, as I think we all know that it's the motivating example for this
text.

Thanks,
--David (as individual participant, *not* as WG chair)
----------------------------------------------------
David L. Black, Senior Technologist
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email protected]        Mobile: +1 (978) 394-7754
----------------------------------------------------

> -----Original Message-----
> From: Dave Wysochanski [mailto:[email protected]] 
> Sent: Friday, March 31, 2006 9:35 PM
> To: Black, David
> Cc: [email protected]
> Subject: Re: [Ips] X#NodeArchitecture draft - next steps
> 
> [email protected] wrote:
> 
> > This draft is better known as: 
> > draft-wysochanski-xkey-iscsi-support-00.txt
> >
> > This draft will be an official WG draft, but three things
> > need to happen first:
> >
> > (1) New security text.  The existing "SHOULD" in the security
> >         considerations text needs to be a "MUST".  In addition,
> >         there needs to be a sentence pointing out that it may
> >         be important to shield the contents of this key from
> >         observers of network traffic, and that IPsec as specified
> >         for iSCSI in RFC 3720 and 3723 (cite both of them) is an
> >         appropriate tool for this purpose.
> >
> New proposed text:
> 
> 3.  Security Considerations 
> 
>    In certain environments where security is a primary concern,
>    the use of this extension key may not be appropriate as it
>    reveals specific details about an iSCSI node.  For these
>    environments, nodes implementing this public extension key
>    MUST provide a method to disable sending the key.  In
>    addition to providing a disable mechanism, security sensitive
>    environments SHOULD consider use of IPsec, as specified in 
>    RFC 3720 and 3723, as a means to shield the contents of this
>    key from observers of network traffic.
> 
> 
> 
> Original text: 
> 
> 3.  Security Considerations 
> 
>    In certain environments where security is a primary concern,
>    the use of this extension key may not be appropriate as it
>    reveals specific details about an iSCSI node. For these
>    environments, nodes implementing this public extension key
>    SHOULD provide a method to disable sending the key.
> 
> 
> 
> > (2) New "prevention of abuse" text.  The current "The key MUST NOT
> >         be used by iSCSI nodes for things such as ..." is well-
> >         intentioned but does not get the job done.  My recollection
> >         of discussion in Dallas is that saying that "functional 
behavior
> >         of the iSCSI node MUST NOT depend on this key 
(presence/absence
> >         or value)"  may be closer to the mark.  The only permitted
> >         (and intended) use of this key is to report it/log it in order
> >         to avoid the browser detection JavaScript disasters caused by
> >         the corresponding HTTP header fields.
> >
> 
> I wasn't sure about deleting the original "MUST NOT" sentence so I left 
it
in.  Anyone
> have a preference?  Also wasn't sure whether it's worth putting in a
sentence or two at
> least acknowledging what has happened in the past with User-Agent --
intent would be
> the working group acknowledges this historical misuse and wishes to 
avoid
it.
> 
> New proposed text:
> 
>    The following described Public Extension Key is sent during
>    the login phase of an iSCSI normal session.  It is important
>    to note that the proper use of this key is to provide enhanced
>    logging and support capabilities, and for better understanding
>    of customer environments.  Functional behavior of the iSCSI
>    node MUST NOT depend on the presence, absence, or content of
>    the key.  The key MUST NOT be used by iSCSI nodes for things
>    such as interoperability, performance, exclusion or deception
>    of other nodes, or other uses not defined here.  To enforce
>    proper use, iSCSI nodes MUST NOT allow user modification of
>    the key value(s), and SHOULD set the value automatically based
>    on standard internal interfaces.
> 
> 
> 
> Original text:
> 
>    The following described Public Extension Key is sent during
>    the login phase of an iSCSI normal session.  It is important
>    to note that the proper use of this key is to provide enhanced
>    logging and support capabilities, and for better understanding
>    of customer environments.  The key MUST NOT be used by iSCSI
>    nodes for things such as interoperability, performance,
>    exclusion or deception of other nodes, or other uses not
>    defined here.  To enforce proper use, iSCSI nodes MUST NOT
>    allow user modification of the key value(s), and SHOULD set
>    the value automatically based on standard internal interfaces.
> 
> 
> 
> 
> 
> 
> > (3) The draft needs a new title and file name ("supportability" just
> >         reeks of marketing ;-) ).  Let's try:
> >
> >            The iSCSI X#NodeArchitecture Key
> >         draft-ietf-ips-iscsi-nodearch-key-00.txt
> >
> Sounds fine to me.
> 
> 
> > Text for (1) and (2), or at least initial versions of it should be
> > worked out on the list before the -00 version of the 
draft-ietf-ips-...
> > draft is submitted.  I've just sent the request to the secretariat for
> > an end-of-2006 completion milestone for this, but in practice, it
> > could be done shortly after Montreal, if not before.
> >
> Great, thanks.
> 
> > Thanks,
> > --David
> > ----------------------------------------------------
> > David L. Black, Senior Technologist
> > EMC Corporation, 176 South St., Hopkinton, MA  01748
> > +1 (508) 293-7953             FAX: +1 (508) 293-7786
> > [email protected]        Mobile: +1 (978) 394-7754
> > ----------------------------------------------------
> >
> > _______________________________________________
> > Ips mailing list
> > [email protected]
> > https://www1.ietf.org/mailman/listinfo/ips
> >
> 

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