Subject: Re: Last Call: Telnet Authentication Option to Proposed Standard

From: Jeffrey Altman <[email-masked]>
Date: Tue, 23 Nov 99 9:06:40 EST

> The IESG <[email-masked]> writes:
> 
> > o Telnet Encryption: DES3 64 bit Cipher Feedback 
> > 	<draft-altman-telnet-enc-des3-cfb-01.txt> 
> > o Telnet Encryption: DES3 64 bit Output Feedback 
> > 	<draft-altman-telnet-enc-des3-ofb-01.txt> 
> 
> Do these make sense at all? Do they provide any better security than
> single des?
> 
> I haven't seen any discussion.
> 
> /Johan
> 

I'm not sure that I understand the motivation behind the question.
You are questioning the use of Triple DES but not the use of
CAST-128.  Both are stronger ciphers than single DES but only if you
have enough available key info.

When using the current Kerberos implementations there is only enough
key info a single DES key which is used in both directions.  Other
authentication methods provide enough key info for the 3DES to use
6 different DES keys with a Triple DES implementation (3 in each
direction). 

    Jeffrey Altman * Sr.Software Designer * Kermit-95 for Win32 and OS/2
                 The Kermit Project * Columbia University
              612 West 115th St #716 * New York, NY * 10025
  http://www.kermit-project.org/k95.html * [email-masked]

---

From: [email-masked] (Johan Danielsson)
Date: 23 Nov 1999 16:15:11 +0100

Jeffrey Altman <[email-masked]> writes:

> CAST-128.

I'm questioning the use of DES3 in anything but EDE on outer CBC
mode. There is a paper by Eli Biham about other combinations, which
basically says that most of them are not much better than single DES.

Even though this paper doesn't talk about this specific use, it's not
obvious that it's more secure to use DES3 to generate random numbers
than it is to use single DES.

Has this case been analysed by anyone?

/Johan

---

From: [email-masked] (Johan Danielsson)
Date: 23 Nov 1999 16:15:11 +0100

/Johan

---

From: [email-masked]
Date: Tue, 23 Nov 1999 15:06:14 -0500

From: [email-masked] (Johan Danielsson)
   Date: 23 Nov 1999 16:15:11 +0100

The telnet encryption specification provides confidentiality but *not*
integrity guarantees.  It is using CFB/OFB because it is stream
oriented, and this *is* known weakness, and is discussed in the drafts.

Personally, I wouldn't have bothered with the triple-DES telnet
encryption mode, on the grounds that because it is a very weak mode, it
doesn't provide much protection.  However, Jeffery lobbied for them on
the grounds that they were being used in some existing implementations
(I don't remember which one, but it wasn't Kerberos V5), and that we
should document what some implementations are using today.

							- Ted

---

From: [email-masked]
Date: Tue, 23 Nov 1999 15:06:14 -0500

- Ted

---

From: [email-masked] (Johan Danielsson)
Date: 23 Nov 1999 23:09:35 +0100

[email-masked] writes:

> However, Jeffery lobbied for them on the grounds that they were
> being used in some existing implementations (I don't remember which
> one, but it wasn't Kerberos V5), and that we should document what
> some implementations are using today.

I'm all for documenting things. What I'm trying to say is that there
might be a danger in having situations where people think that just
because it's using DES3 it's three times as secure, which might not be
the case.

/Johan

---

From: [email-masked] (Johan Danielsson)
Date: 23 Nov 1999 23:09:35 +0100

/Johan

---

From: Harald Tveit Alvestrand <[email-masked]>
Date: Tue, 23 Nov 1999 23:18:59 +0100

>should document what some implementations are using today.
Protocols that offer increased complexity but no gain in security or 
efficiency over other standards-track efforts, but are in use today, are 
IMHO excellent candidates for Informational publication.

Not for the standards track.

                Harald A

--
Harald Tveit Alvestrand, EDB Maxware, Norway
[email-masked]

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From: Harald Tveit Alvestrand <[email-masked]>
Date: Tue, 23 Nov 1999 23:18:59 +0100

Harald A

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From: William Allen Simpson <[email-masked]>
Date: Tue, 23 Nov 1999 19:21:47 -0500

> Not for the standards track.
I'll go further.  THIS ENTIRE PROTOCOL DUPLICATES OTHER STANDARDS TRACK 
EFFORTS.  I see no reason why it should rise above Experimental and 
Informational.

We already have authentication and encryption at link layer (PPP), 
network layer (IPSec), transport layer (TLS), and session layer 
(SecSHell).  Why do we need application layer security, too?

If this were "just" authentication, just as new authentication modes 
have been added to protocols (POP3, SMTP) that already have some form of 
authentication, it might be useful.  But, Telnet has no extant 
authentication that is being improved.  This is a whole new set of 
features, including encryption (not mentioned in the announcement).  
Why bother?

Moreover, there is no _required_ option that must be implemented.  One 
of the most important interoperability design principles is violated.  

Finally, the protocol itself seems insecure and subject to denial of 
service and monkey in the middle attacks.  It's a bad idea.

[email-masked]
    Key fingerprint =  17 40 5E 67 15 6F 31 26  DD 0D B9 9B 6A 15 2C 32

---

From: William Allen Simpson <[email-masked]>
Date: Tue, 23 Nov 1999 19:21:47 -0500

[email-masked]

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From: Assar Westerlund <[email-masked]>
Date: 25 Nov 1999 08:20:17 +0100

> should document what some implementations are using today.

Shouldn't they be made informative rather than proposed standard in
that case?

/assar

---

From: Assar Westerlund <[email-masked]>
Date: 25 Nov 1999 08:20:17 +0100

/assar

---

From: Pete Loshin <[email-masked]>
Date: Fri, 26 Nov 1999 09:14:55 -0500

Hi. I'm trying to track down some information about IP network address
allocations/assignments. Specifically, I'm looking for some reasonable
estimate of the number/proportion of Class B/Class C networks that have
been assigned out of the entire amount possible.

The allocation of address space to registries (and Class A assignments) is
available at:

http://www.isi.edu/in-notes/iana/assignments/ipv4-address-space

And I know that the IMRs (Internet Monthly Reports) used to contain monthly
updates of network assignments by class--but that series ended (didn't it?)
and of the ones I've read, some are missing those figures. So that's not a
practical solution.

I'm pretty sure that I've seen figures about the total number of Class
B/Class C networks assigned (and/or allocated to ISPs for reassignment).
I'd be very grateful if someone could point me in the right direction.

Thank you!
-pl

+-------------------------------------------------------------+
| Pete Loshin                    http://Internet-Standard.com |
|                                                             |
| _IPv6 Clearly Explained_ Morgan Kaufmann January 1999       |
| _TCP/IP Clearly Explained_ 3rd ed Morgan Kaufmann June 1999 |
|                                                             |
+-------------------------------------------------------------+

---

From: Pete Loshin <[email-masked]>
Date: Fri, 26 Nov 1999 09:14:55 -0500

Thank you!
-pl

---

From: Henning Schulzrinne <[email-masked]>
Date: Fri, 26 Nov 1999 10:17:25 -0500

> -pl

http://ipv4space.TopLayer.Com/ has some information

-- 
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs

---

From: Henning Schulzrinne <[email-masked]>
Date: Fri, 26 Nov 1999 10:17:25 -0500

---

From: "David Newman" <[email-masked]>
Date: Fri, 26 Nov 1999 10:42:32 -0800

Telcordia's Christian Huitema conducts an ongoing survey that counts, among
other things, the amount of allocated IPv4 space and number of hosts in
classes A, B, and C. You can find a recent sample here:

ftp://ftp.telcordia.com/pub/huitema/stats/oct99.html#efficiency

Regards,
David Newman
Network Test

> -----Original Message-----
> From: Pete Loshin [mailto:[email-masked]]
> Sent: Friday, November 26, 1999 6:15 AM
> To: [email-masked]
> Subject: IP network address assignments/allocations information?
>
>
> -
> This message was passed through [email-masked], which
> is a sublist of [email-masked]. Not all messages are passed.
> Decisions on what to pass are made solely by Harald Alvestrand.
>

---

From: "David Newman" <[email-masked]>
Date: Fri, 26 Nov 1999 10:42:32 -0800

Regards,
David Newman
Network Test

---

From: Bill Manning <[email-masked]>
Date: Fri, 26 Nov 1999 07:57:59 -0800 (PST)

> been assigned out of the entire amount possible.

	Well, first off, the idea of class has been OBE. RFC 1519 pretty much
killed class.  If you are asking about the distributionss in the historic
/a/b/c ranges, some of that type of data is being collected/published at
www.isi.edu/~bmanning/in-addr-audit.html
	It does not cover specific /16 & /24 delegations, it just looks at
all of the SOA entries. Still, it does give a representation of how much
space is delegated.

-- 
--bill

---

From: Bill Manning <[email-masked]>
Date: Fri, 26 Nov 1999 07:57:59 -0800 (PST)

-- 
--bill

---

From: Henning Schulzrinne <[email-masked]>
Date: Fri, 26 Nov 1999 11:38:54 -0500

> ftp://ftp.telcordia.com/pub/huitema/stats/oct99.html#efficiency

I noticed a rather strange number in that page:

6,989,652 hosts are listed for Lucent. Lucent has 153,000 employees, so
every employee has 45 hosts. Either they have been equipping every
pencil, badge and styrofoam cafeteria tray with a host name, or the
measurement methodology needs some explanation...

I know they export every IP address as H-135-X-X-X.lucent.com, but
that's not 6 million.

---

From: Henning Schulzrinne <[email-masked]>
Date: Fri, 26 Nov 1999 11:38:54 -0500

---

From: Randy Bush <[email-masked]>
Date: Fri, 26 Nov 1999 10:53:02 -0800

> all of the SOA entries. Still, it does give a representation of how much

uh, as these data appear to be the statistics of an attempt to walk the
dns in-addr.arpa tree what confidence is there that this fairly represents
address space assignment/allocation?

e.g. there are 153 /16 announcements in 133.0.0.0 and the table at
http://www.isi.edu/~bmanning/in-addr-data.html shows one in-addr.arpa
allocation entries.

e.g. there are 166 announcements (of 175 /16 equivalents of space) in
147.0.0.0 and the table at http://www.isi.edu/~bmanning/in-addr-data.html
shows 193 in-addr.arpa entries.

so how can the data at www.isi.edu/~bmanning/in-addr-audit.html be
interpreted to give a useful representation of how much space is
assignmed/allocated?

randy

---

From: Randy Bush <[email-masked]>
Date: Fri, 26 Nov 1999 10:53:02 -0800

randy

---

From: Brian E Carpenter <[email-masked]>
Date: Fri, 26 Nov 1999 15:35:32 -0600

Well, let's not focus on Bill's data. Frankly, I haven't seen any data
on this topic from any source that really convinces me that it
means much. All I know is that we have thousands of sites using
private address space, which completely falsifies any real data and
makes it impossible to attach any real meaning to concepts such as
"running out of addresses". My personal opinion is that we ran out
of addresses in practical terms around about when RFC 1597 was published.

  Brian

---

From: Brian E Carpenter <[email-masked]>
Date: Fri, 26 Nov 1999 15:35:32 -0600

Brian

---

From: Randy Bush <[email-masked]>
Date: Fri, 26 Nov 1999 16:05:36 -0800

> All I know is that we have thousands of sites using private address space,
> which completely falsifies any real data and makes it impossible to attach
> any real meaning to concepts such as "running out of addresses".

the original question was not whether address panic was justified.  it asked
for data on assignments/allocations.  these are real measurable numbers
which should be easily available, not a platform for political or social
grandstanding.

randy

---

From: Randy Bush <[email-masked]>
Date: Fri, 26 Nov 1999 16:05:36 -0800

randy

---

From: Marc Blanchet <[email-masked]>
Date: Sun, 28 Nov 1999 14:05:25 -0500

>means much. All I know is that we have thousands of sites using

sorry, many many many thousands of sites.  for example, I would fairly 
guess these days that 75% of sites use private address space. I would say 
that 90% of the networks I've seen at our clients sites are using private 
address space.

I would say that now, a lot of global ipv4 address space is used mostly for 
the outside interfaces of sites: i.e. firewall external address, 
web/smtp/... external servers.

Marc.

> > interpreted to give a useful representation of how much space is

-----------------------------------------------------------
Marc Blanchet			| [email-masked]
Viagénie inc.			| http://www.viagenie.qc.ca
2875 boul. Laurier, suite 300	| tél.: 418-656-9254
Ste-Foy, Québec		| fax.: 418-266-5539
Canada, G1V 2M2		| radio: VA2-JAZ
------------------------------------------------------------
Internet Engineering Standards/Normes d'ingénierie Internet
                http://www.normos.org
------------------------------------------------------------

---

From: Marc Blanchet <[email-masked]>
Date: Sun, 28 Nov 1999 14:05:25 -0500

Marc.

---

From: Christian Huitema <[email-masked]>
Date: Mon, 29 Nov 1999 11:04:59 -0500

Henning,

Lucent does indeed advertize the 6M+ addresses reported on the page. The
135/8 prefix was allocated to ATT in the early 80's, in addition to ATT's
own class A. I was told that the class B numbers in that prefix had been
allocated to various subnet within ATT. After the ATT/Lucent split, Lucent
inherited a fraction of the 135/8 prefix, presumably the class B networks
addresses that covered subnets in the various Lucent facilities. The 6M+
make up about 41% of the 16777216 addresses in a /8.  In January 1999,
Lucent started to announce all these addresses in their DNS server. Don't
ask me why they do that, or whether they would consider returning unused
blocks to the community. We are merely reporting what we observe... See
ftp://ftp.telcordia.com/pub/huitema/stats/index.html or
http://www.netsizer.com/ for more details on our methodology. 

>I know they export every IP address as H-135-X-X-X.lucent.com, but

-- Christian Huitema

---

From: Christian Huitema <[email-masked]>
Date: Mon, 29 Nov 1999 11:04:59 -0500

Henning,

-- Christian Huitema