January CRYPTO-GRAM newsletter

                  CRYPTO-GRAM

                January 15, 2003

               by Bruce Schneier
                Founder and CTO
       Counterpane Internet Security, Inc.
            schneier@counterpane.com
          <http://www.counterpane.com>


A free monthly newsletter providing summaries, analyses, insights, and 
commentaries on computer security and cryptography.

Back issues are available at 
<http://www.counterpane.com/crypto-gram.html>.  To subscribe, visit 
<http://www.counterpane.com/crypto-gram.html> or send a blank message 
to crypto-gram-subscribe@chaparraltree.com.

Copyright (c) 2003 by Counterpane Internet Security, Inc.


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In this issue:
      Militaries and Cyber-War
      Crypto-Gram Reprints
      The Doghouse: Yahoo
      News
      Counterpane News
      Security Notes from All Over:  Cichlids
      The RMAC Authentication Mode
      Comments from Readers


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            Militaries and Cyber-War



Recently I was interviewed by an Iranian newspaper on the subject of 
computer security.  One of the questions I was asked was whether or not 
the Pentagon had a secret weapon that could disable the Internet.

It's an interesting question.  I have no idea what the real answer is, 
but I can certainly speculate.

There's no doubt that the smarter and better-funded militaries in the 
world are planning for cyberwar, both attack and defense.  It's a 
multifaceted concept.  A military might target the enemy's 
communications infrastructure through both physical attack -- bombings 
of selected communications facilities and transmission cables -- and 
virtual attack.  It would be foolish for a military to ignore the 
threat and not invest in defensive capabilities, or to ignore the 
possibility of launching an offensive cyber-attack against an enemy 
during wartime.  And while history has taught us that many militaries 
are indeed foolish, some are not.

This implies that at least some of our world's militaries have Internet 
attack tools that they're saving in case of wartime.  They could be 
denial-of-service tools.  They could be exploits that would allow 
military intelligence to penetrate military systems.  They could be 
viruses and worms similar to what we're seeing now, but perhaps 
country- or network-specific.  I can certainly imagine a military 
finding a new vulnerability in a common operating system or software 
package and keeping it secret, hoping to use that vulnerability to 
their advantage in wartime.

So my guess is that the U.S. military could disable large parts of the 
Internet, at least for a while, if they wanted.  But I doubt that they 
would do so; it's far too useful an asset, and far too large a part of 
our economy.  More interesting is whether they would try to disable 
pieces of it.  If we went to war with country X, would we want to 
disable their portion of the Internet, or remove connections between 
their Internet and our Internet?  Depending on the country, a low-tech 
solution might be the easiest: disable whatever undersea cables they're 
using as access.  Could the U.S. military turn the Internet into a 
U.S.-only network if they wanted?  That seems less likely, although 
again a low-tech solution involving the acquiescence of companies like 
Cable & Wireless might be the easiest.

One important thing to remember here is that you only want to shut an 
enemy's network down if you aren't getting useful information from 
it.  The best thing to do is to infiltrate the enemy's computers and 
networks, spy on them, and surreptitiously disrupt select pieces of 
their communications when appropriate.  The next best thing is to 
passively eavesdrop.  After that, the next best is to perform traffic 
analysis.  Only if you can't do any of that do you consider shutting 
the thing down.

When a military discovers a vulnerability in a common product, they can 
either alert the manufacturer and fix the vulnerability, or not tell 
anyone.  In U.S. military circles, this is called the equities 
issue.  It's not an easy decision.  Fixing the vulnerability gives both 
the good guys and the bad guys a more secure system.  Keeping the 
vulnerability secret means that the good guys can exploit the 
vulnerability to attack the bad guys, but it also means that the good 
guys are vulnerable.

Script kiddies are attackers who run exploit code written by others, 
but don't really understand the intricacies of what they're 
doing.  Professional attackers spend an enormous amount of time 
developing exploits: finding vulnerabilities, writing code to exploit 
them, figuring out how to cover their tracks.  The real professionals 
don't release their code to the script kiddies; the stuff is much more 
valuable if it remains secret.  I believe that some militaries have 
collections of vulnerabilities, and code to exploit those 
vulnerabilities, that they are saving in case of wartime or other 
hostilities.  It would be irresponsible for them not to.


My interview in the Iranian newspaper.  (To be honest, I have no idea 
what it says.)
<http://www.jamejamdaily.net/shownews2.asp?n=26454&t=com>


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             Crypto-Gram Reprints



Crypto-Gram is currently in its sixth year of publication.  Back issues 
cover a variety of security-related topics, and can all be found on 
<http://www.counterpane.com/crypto-gram.html>.  These are a selection 
of articles that appeared in this calendar month in other years.

A cyber Underwriters Laboratories?
<http://www.counterpane.com/crypto-gram-0101.html#1>

Code signing:
<http://www.counterpane.com/crypto-gram-0101.html#10>

Block and stream ciphers:
<http://www.counterpane.com/crypto-gram-0001.html#BlockandStreamCiphers>


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            The Doghouse: Yahoo



When you register for a Yahoo account, they ask you for your date of 
birth.  The purpose is security; if you forget your password, they can 
authenticate you with this information.  Someone's birthdate isn't a 
secret, and is a terrible way to authenticate someone.  But Yahoo goes 
one step further.  "My Yahoo," the company's popular personalized news 
page, uses the information to put a "Happy Birthday, <username>!" 
message at the top of your page when you visit on your birthday.

An excellent example of not getting it.

<http://www.oreillynet.com/pub/wlg/2597>


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                      News



Government report says cyberterrorism threat is overhyped.
<http://www.wired.com/news/infostructure/0,1377,56935,00.html>

Even Microsoft agrees: don't trust Microsoft:
<http://www.infoworld.com/articles/op/xml/02/12/09/021209opwinman.xml>

Elcomsoft not guilty of violating the DMCA.
<http://www.wired.com/news/business/0,1367,56853,00.html>
<http://sanjose.bizjournals.com/sanjose/stories/2002/12/16/daily28.html>
<http://www.wired.com/news/business/0,1367,56898,00.html>

Evaluating intrusion detection systems:
<http://online.securityfocus.com/infocus/1623>
<http://online.securityfocus.com/infocus/1630>
<http://online.securityfocus.com/infocus/1651>

Insider accused of attempting to manipulate stock price by sabotaging 
computer.
<http://www.vnunet.com/News/1137678>
<http://www.theregister.co.uk/content/55/28630.html>

Another essay on full disclosure:
<http://www.osopinion.com/perl/story/20319.html>

The strategic effectiveness of suicide terrorism:
<http://magazine.uchicago.edu/0212/research/invest-terror.html>
<http://www.plastic.com/article.html?sid=02/12/23/23150192;cmt=60>

Good piece on Total Information Awareness:
<http://www.newyorker.com/talk/content/?021209ta_talk_hertzberg>

Even though there are thousands of hackable holes in computer systems, 
only a very few of them are actually exploited in bulk:
<http://www.wired.com/news/infostructure/0,1377,56955,00.html>

There's a new version of the Bush Administration's cyber-security 
plan.  Incentives to tighten network security are reduced, more 
authority is given to the Department of Homeland Security, and they're 
no longer going to consult regularly with privacy experts.  It'd all 
worry me more if I thought this plan had any real effects.
<http://www.wired.com/news/conflict/0,2100,57109,00.html>

More DMCA abuse, this one about printer toner cartridges:
<http://news.com.com/2100-1023-979791.html>
Europe is banning this practice:
<http://www.geek.com/news/geeknews/2002Dec/gee20021223017885.htm>
This has the makings of a trade war between the U.S. and the EU.

While we're on the subject, the EFF has written an excellent article 
about the unintended consequences of the DMCA:
<http://www.eff.org/IP/DMCA/20030102_dmca_unintended_consequences.html>

The U.S. government is looking for input on sentencing guidelines for 
hackers:
<http://online.securityfocus.com/news/2028>

Another excellent essay by Tim Mullen on "strike back" (see also the 
various comments in the letter column, below).  I disagree with some of 
this, but I am happy to see intelligent debate on this issue.
<http://online.securityfocus.com/columnists/134>


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                Counterpane News



The news that I couldn't talk about for the past month and a half is 
that Counterpane has received another round of funding.  We have 
another $20M, which is more than enough to fund the company until we 
reach break-even, and to allow us to expand our services.  It's a tough 
economic climate out there, and the fact that we got this much money 
from a list of impressive investors is a source of pride for me.

Meanwhile, Counterpane continues its quest for world domination in the 
Managed Security Monitoring space.  The fourth quarter of 2002 was our 
best quarter ever, and the year was our best year ever.  I'll spare you 
the details; they're in the press release if you want to read them.

And Counterpane has hired a new CFO and COO.  Press releases announcing 
these changes will be out soon.

Funding press release:
<http://www.counterpane.com/pr-seriesd.html>

Fourth quarter press release:
<http://www.counterpane.com/pr-2002q4.html>


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     Security Notes from All Over:  Cichlids


Midas cichlids have biparental care; both father and mother fish watch 
over the fry.  Unfortunately for them, they still lose a lot of their 
young to predators.  So to avoid losing too many of their own babies, 
they actually go out and kidnap the fry of other Midas cichlids, or 
even other species of fish.  (In one case, while one pair of Midas 
cichlids was fighting another pair, the male of a third pair sneaked in 
and took about fifty fry back to his own territory.)  Predators are 
just as happy to eat the adopted fry as the parents' own young, so as 
long as the larger school of fry doesn't attract more predators, more 
of the parents' own young will survive.

The convict cichlid also practices adoption, but is fussier:  it will 
only adopt fry that are smaller than its own.  Predators will tend to 
attack the smaller adopted fry because they're easier pickings.

[paraphrased from George W. Barlow, _The Cichlid Fishes: Nature's Grand 
Experiment in Evolution_, p. 202-203]


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           The RMAC Authentication Mode



As part of the AES process, NIST has embarked on a program to 
standardize various modes of operation for the block cipher.  Aside 
from the encryption modes we're all used to from DES days, NIST is 
trying to standardize on authentication modes as well.

The first mode NIST has proposed is RMAC (Randomized Message 
Authentication Code).  It has the advantage of having a security 
proof.  In fact, if you use triple-DES as the underlying cipher in an 
RMAC construction (the RMAC mode can work with any block cipher), then 
the resulting construction is provably secure.  But this is the very 
same construction that Lars Knudsen broke in a recent paper.

What's going on here?  On the one hand, RMAC is a provably secure 
mode.  On the other hand, there's a working attack against it.  That's 
not supposed to happen!

Let's take things one at a time...

RMAC is secure in something called the ideal cipher model.  As part of 
that model's assumptions, the underlying block cipher needs to be 
secure against a variety of attacks, including related-key attacks.  If 
a block cipher is susceptible to related-key attacks, then it would be 
inappropriate to model it as an ideal cipher and the RMAC security 
proof would not apply.

Now if triple-DES can be modeled by an ideal cipher, then 
triple-DES-RMAC ought to be secure.  In fact, NIST's RMAC standard 
includes triple-DES-RMAC is one of the two options.  (AES-RMAC is the 
other.)   However, it's been shown that triple-DES is not secure 
against related-key attacks.  Even worse, it is this related-key 
property that Knudsen uses to break triple-DES-RMAC.  His attack 
requires 2^16 chosen messages and about 2^56 work, which makes it 
practical with today's computing resources.

So now we can explain what happened.  The proof of security for RMAC 
only works if you assume use of an ideal cipher.  If you want to draw 
any conclusions about RMAC with a real block cipher like triple-DES or 
AES, you have to hope that your real block cipher behaves enough like 
an ideal cipher that the same proof still carries over.  In the case of 
triple-DES, that hope turned out to be false.  Triple-DES is not well 
modeled as an ideal cipher, because triple-DES is vulnerable to 
related-key attacks.  And as Knudsen showed, if there are related-key 
attacks on your real block cipher, this not only renders the proof 
irrelevant and "invalidates the security warranty," it can also lead to 
serious attacks on RMAC.

At this point, the most interesting question is whether AES-RMAC is 
secure.  If you want to think that the proof of security for RMAC says 
anything about AES-RMAC, you have to hope that AES behaves like an 
ideal cipher.  One necessary condition for the latter is that AES must 
be secure against related-key attacks.

AES is a new cipher, and the security of it against related-key attacks 
has not been well-studied.  For the most part, cryptanalysts focus on 
the standard threat model (chosen plaintext/ciphertext attacks), and 
related-key attacks are only occasionally studied.  What little we do 
know about the security of AES against related-key attacks suggests 
that AES has considerably less strength against related-key attacks 
than against normal attacks: the best related-key attack (found after 
only a few weeks of analysis) breaks nine rounds.

The lesson here is that the ideal cipher model is not as powerful a 
tool as some think it is, and a mode of operation that is secure in 
that model isn't necessarily secure in practice.  Cryptography theory 
is mature enough to base designs on, but there's still no substitute 
for detailed cryptanalysis.  RMAC should not become a NIST standard.


NIST RMAC Specification:
<http://csrc.nist.gov/publications/drafts/draft800-38B-110402.pdf>

NIST Modes of Operation page:
<http://csrc.nist.gov/encryption/modes>

Comments on RMAC:
<http://csrc.nist.gov/encryption/modes/comments/>
The analyses of David Wagner, Phil Rogaway, and Lars Knudsen are 
especially worth reading.

Related-key attacks against triple-DES:
<http://www.counterpane.com/key_schedule.html>

Related-key attacks against AES:
<http://www.counterpane.com/rijndael.html>

This article was written with the help of David Wagner.


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             Comments from Readers



From: "Jennifer S. Granick" <jennifer@granick.com>
Subject: Counterattack

The noisemaking analogy is an interesting one because it relates to an 
argument we're making in the Intel v. Hamidi case, where Intel got an 
injunction stopping Hamidi from sending e-mails to intel.com 
addresses.  Intel argues that the e-mail servers are their private 
property, and they have the right to exclude people from use of their 
property, as they would from their buildings, or from use of their 
car.  We argued that extending that kind of private property right to 
the networked world would mean that the Internet is not a public 
commons but a series of private fiefdoms, a model detrimental to 
socially beneficial uses.  We suggested that the problem of spam and 
unwanted e-mail is best considered as a nuisance problem, exactly the 
way the law looks at things like too much noise coming from one 
property and washing over into the next.  The properties share a common 
thing, air or "ether" as the case may be, and rather than the absolute 
right to exclude, the court should weigh the harm to and interests of 
each party in determining whether anyone has the right to stop Hamidi 
from sending the e-mail from his own property.

I like that you immediately went for the commons/nuisance model, rather 
than the strict private property model.  It makes me feel that nuisance 
is intuitively right to those familiar with the Internet.  Of course, 
if you were a lawyer arguing this point, you'd adopt the stricter 
property view and say that the strikeback targets have the absolute 
right not to be patched, etc. because that's the stronger right.

In the nuisance context, since there's a balance of rights and harms, 
the law really is your only recourse.  Going over there and taking the 
stereo is not allowed.  But there are concepts like self-defense and 
defense of others that permit the violation of others' personal and 
property rights in certain narrow cases.  It depends on what interest 
you're protecting, person or property, and whether you've only 
counter-attacked to the extent necessary to protect that interest and 
no further.



From: "Tim Mullen" <Thor@HammerofGod.com>
Subject: Counterattack

When it comes to the MPAA, I absolutely agree -- but there are several 
key differences between what people like Berman are proposing and what 
I am doing...  For one, there is already a framework of law and 
protocol for copyright holders to seek remedy.  Copyright law is 
extensive, and has a long history of case law.  The Berman bill will 
provide for a copyright holder to circumvent this existing framework in 
order to take immediate action against alleged acts of copyright 
infringement.  More importantly, the spirit of the bill/action is much 
different.  We seek to impede the propagation of global worms.  Our 
actions against the attacking system are limited specifically to the 
scope of the attacking process -- no other action is taken against the 
system or other processes.  No harm is caused to the attacking system, 
or to the administrator/owner of the system (not purposefully, 
anyway.)  The entire basis of the Berman bill is to allow the copyright 
holder to inflict willful and substantial "damage" against the alleged 
system and owner to the degree that they will stop the alleged 
activity.  They *want* to hurt the end user -- they want to cause 
enough trouble for the user that they will give up.

There is no framework in place to which to take guidance when it comes 
to protecting our property and equipment from constant attack.  There 
needs to be.  The other big difference is that the Berman bill proposes 
that the copyright holder can take action against people *who are 
committing a crime*.  The alleged activity is against the law -- here, 
when you set up a Win2k box on the net and it gets Nimda and attacks 
everyone non-stop, it is *not* a crime.  There is nothing illegal about 
being stupid, or not knowing how to secure a system.

We have to look at this within the confines of stopping an attacking 
process -- we can't make it "personal" as if we are doing something 
against the people who own these boxes.  And actually, the law supports 
this differentiation:  If I personally set up a Win2k box at default, 
knowing that it will be compromised in 10 minutes and start attacking 
"close" boxes to me, I have not committed a crime.  However, if I run a 
Perl script that executes the same exact GET requests against the exact 
same boxes, I have committed a felony.

If the tie between administrator and the actions of his equipment 
cannot support culpability for actions in tort (as in them being 
responsible for their computer getting Nimda), how can we support the 
same logic required to say that we are infringing upon the 
administrator's rights when we neutralize the attack?  Why are we 
pretending that the box has rights?

Even if we do take the stance that the box has some implicit right, we 
should treat it like we do a criminal -- if a person's actions show 
that they cannot operate in society without hurting other people or 
infringing upon their rights, we take their rights away, and keep them 
from doing so.  The very infestation of a system by a worm shows that 
it is not configured in a state that it should be to participate in a 
global network -- therefore, it loses some rights (that I don't think 
it should have in the first place).

Homeowner-type analogies never really work; there is just too much one 
can say one way or the other to fit the desired outcome.  Do I get to 
trespass on a neighbor's property to disable the noisemaker?  Probably 
not, but one might actually be able to under certain nuisance law.  I 
could always say back that if my bike was stolen, and I saw it in your 
yard, I certainly do have the right to go onto your property and take 
it back -- the law says I can.  So where does it stop?

If you really wanted the analogy to be accurate to this issue, we would 
have to say that the house alarm not only caused noise of its own, but 
that it made other house alarms around it go off, which made other 
house alarms around them go off, etc, etc.  Pretty soon, everyone has 
to shout just to be heard.  None of this noise is against the law, so 
the police won't help you.  The manufacturer of the alarms says that it 
is the homeowner's fault for not knowing how to install them and that 
it is not their problem.  Further, all the criminals know that the 
homes with the alarms going off are completely wide open, so they use 
the alarm signal to hunt down homes to take over to use for some future 
illegal activity.  The really bad thing is that when you try to talk to 
the neighbors about all the noise, they say "What noise?  We don't hear 
any noise.  Go away."



From: John Kelsey <kelsey.j@ix.netcom.com>
Subject: Counterattack

Just a nitpick on your counterattack article: I don't think justice 
depends on the government doing the punishment.  (Think of a really 
corrupt government, where the punishment is always done to the person 
who paid the lowest bribe.)  Having a neutral third party investigate 
the facts and decide what punishment or restitution should be made is a 
way to try to get justice in punishment or restitution, but it's 
neither the only way to get it nor guaranteed to get it.  And that 
neutral third party may or may not be the government.

A really obvious example of justice being done by non-governments is 
when a parent successfully determines which kid started the fight and 
assigns punishments appropriately.

It seems obvious that automated counterattacks are a bad idea in nearly 
all cases.  Not only do you have a real hard time guaranteeing that 
your automated system correctly identified the attacker, you also have 
a hard time guaranteeing that the owner of the counterattacking system 
didn't generate the evidence of the initial attack on his own to 
justify his counterattack.  And you can easily imagine a "war" starting 
between two or three such systems.  (Note that all of these are 
problems that appear in vigilante justice, as well -- the lynch mob 
hangs the wrong guy, the lynch mob is started by a false accusation by 
the target's enemies, or you lynch me, and then my friends and family 
lynch you.)



From: Paul Mantyla <pjm1212@yahoo.com>
Subject: Counterattack

In the December 15 Crypto-Gram, you state, "Our laws give us the right 
to justice..."  This is too strong a statement and your statements that 
follow fail to correct the error.  Only an omniscient being is able to 
determine what is just.

Our best approximation is a set of laws and civil rights.  As Oliver 
Wendell Holmes famously remarked, "This is a court of law, young man, 
not a court of justice."  Is it just for a guilty man to go free, or 
for an innocent man to be convicted?  The government is most dangerous 
when it ignores the law and the Constitution in pursuit of 
justice.  For example, in apparent violation of the 5th amendment's 
protection against double jeopardy, the doctrine known as "dual 
sovereign" allows the state and federal governments to prosecute a 
person for the same act (e.g. police officers in the Rodney King case).

See "An Ever-Expanding Double Jeopardy Loophole" in the Cato 
Institute's Handbook for Congress: 
<http://www.cato.org/pubs/handbook/hb105-22.html>.  As citizens of the 
United States, we have a right to many things, but a "right to justice" 
is not one of them.



From: Daniel Upper <upper@peak.org>
Subject:  Counterattack

Until the courts do sort out when counterattack is permissible, I'd 
like to suggest the necessity defense as a way of thinking about 
it.  In general, a defendant is not guilty of violating a law if it was 
necessary to do so.  The criteria for necessity vary somewhat, but they 
generally look about like this:

* The action was done to avert a threat of immediate, significant harm.

* The harm caused by the action was not disproportionate to the harm 
avoided.

* There is no reasonable legal alternative to the action.

* The actor reasonably believed that his/her action would prevent the 
significant harm.

* The defendant did not cause the threat of harm.

This test is fairly stringent and broadly applicable.  Most specific 
emergency exceptions -- e.g., self-defense, emergency medical care by 
non-doctors -- can be looked at as special cases of it.  I expect that 
any counterattack the courts eventually decide to allow will also meet 
these criteria.

Note also that there is nothing here about justice or punishment.  It 
only sanctions preventing harm.


From: Michael Nygard <mtnygard@charter.net>
Subject: Counterattack

There is a nuance to the counter-attack proposals that I wish you had 
discussed in your essay.  The essential difference is between that of 
vengeance and self-defense.  If you are the victim of a crime, then you 
have the right to defend yourself -- during the commission of the crime.

Just as breaking and entering can escalate to robbery-homicide in a few 
chaotic seconds, we must recognize that an intrusion can escalate from 
minor to catastrophic in milliseconds.  Though this point is still 
controversial among law-makers and law-enforcers, self-defense is 
widely viewed as the way to prevent a situation from 
escalating.  Automated counter-attacks perform the same function; 
limiting the amount of damage done by the attacker, perhaps preventing 
the crime from escalating from petty vandalism to grand larceny.

It would be simplistic to say that the same act is self-defense during 
a crime, but vigilantism afterwards.  Still, when law enforcement 
cannot possibly respond during the crime itself, a swift counter-attack 
may be the only protection available.



From: Brian Beesley <BJ.Beesley@ulster.ac.uk>
Subject: Counterattack

There are a couple of points you might have missed:

(1) If it's accepted that X can counterattack you on the grounds that X 
suspects (maybe even has hard evidence) that you are attacking X in 
some way, then why can't you counter-counter-attack?  The point here is 
that if X is the "big guy" and there are lots of people in my position, 
we (acting in concert) are more likely to be able to inflict serious 
damage on X than vice versa.

(2) The counterattack mechanism depends on us leaving our computers 
open to attack and/or engaging in unsafe conduct (e.g., running scripts 
downloaded from Web pages).  This strategy may be fairly successful 
against casual users but will likely have no effect whatsoever on 
anyone who deliberately sets out to act "illegally."

The "Berman bill" is fatally flawed -- not because of its political 
content, but because it fails to address the problem.  The proposed 
legislation is designed to "feel good" to its proposers rather than to 
be effective.

There simply is no need for further legislation, at any rate in most of 
the developed world.  What is needed is the will for those who feel 
they are being robbed of their intellectual property to gather evidence 
which could be presented under existing legislation, rather than just 
moaning about their (dubious) loss of sales.



From: Mike Koptiw <mkoptiw@att.net>
Subject: Counterattack

I agree that vigilantism is morally wrong, and I agree that the state 
is best situated to handle justice.  But, from a legal argument point 
of view, I would make a distinction between strikeback to a DOS attack 
and strikeback to a copyright violation.

As always, it depends.  In some cases, general, common law principles 
of tort actually privilege a victim's action against a 
perpetrator.  First, common law does not privilege the use of force to 
recover lost property.  Our courts resolve these issues.  The law 
handles this, and it does not stand for vigilantism.

However, common law does privilege the use of force in defense of 
property from forcible trespassers.  The force one may use must be 
proportional to eject the trespasser, and once the trespasser has left 
the property, the victim may not pursue the trespasser with force.

So I think that there are common law, theoretical legal arguments for 
strike back in DOS and intrusive hacking cases when there is a virtual 
trespasser (be it a rogue DOS packet or a hacker's presence), but it 
there is no legal leg to stand on when the attack is based solely on 
recovering a right to content on the person's computer (like RIAA's 
proposal).



From: Marko Asplund <aspa@kronodoc.fi>
Subject: Counterattack

In addition to being an ethically and morally questionable idea, I fail 
to see how automated strike-back technology would save the Internet 
from global worm attacks.  Strike-back could perhaps be successfully 
utilized against contemporary worms such as Nimda which decide to leave 
the door open as they come in but it is naive to think that the next 
generation worms will continue to do so.

The definition of clear responsibilities is challenging in case the 
strike-back fails.  Even if the strike-back uses minimal force and 
extreme care is put into crafting the neutralizing code, it is always 
possible that something goes wrong and the target system fails in some 
way after the neutralization.  What if the infected system controls 
life-support systems in a hospital?  If human lives are lost because of 
the strike-back, who is responsible if the system fails to function 
after the strike-back?  There's always a small number of vendor 
software patches which have unexpected results in a small number of 
target systems.  Why wouldn't there be any with strike-back systems?

Mullen draws parallels between self-defense and strike-back, but one 
difference is that a software system on the Internet doesn't have as 
much intelligence or information on the attack context or the attacker 
as a human being under attack would have.  Using your noisy neighbor 
analogy, one could say strike-back is like trying to shut the noisy 
device down using a shotgun...and aiming with a blindfold on.



From: Rick Bressler <bressler@the-bresslers.com>
Subject: Counterattack

After reading this article and reflecting for a bit, I am wondering if 
we're not seeing the beginnings of a "self defense" doctrine on the 
Internet, although at this point much of the legislation is clearly 
misplaced and inappropriate, as is often the case when our lawmakers 
try to adapt to new situations.

I think it bears pointing out that your comparisons to crime in the 
physical world leave out the concept of self-defense completely.  (Is 
this intentional?) In the real world there is a big difference between 
self-defense, a preemptive strike, and vigilantism.  All of these have 
large bodies of case law around them.

Clearly a preemptive strike is illegal.  (Unless you're a government of 
course. :-)) You can't attack somebody just because you think they 
*may* attack you at some future date.

Vigilantism is taking the attack back to your aggressor after the fact, 
or seeking justice on your own.  Clearly this can't be allowed in 
civilized society, nor is it condoned by any legal system I'm aware of, 
although at various times and places it has been overlooked.

Self-defense is a response to the immediate threat of death or grave 
bodily injury.  Does such a doctrine have a place in the cyber 
world?  In your example of somebody actively attacking a machine or 
better yet a critical infrastructure server, and the victim responding 
by shutting them down, we have a situation that to some extent 
parallels the act of self defense in the real world, at least to the 
extent that you are responding to an immediate and possibly serious 
threat.  Perhaps one at least temporarily 'lethal' to the Internet.

Note that in the non-cyber world we typically reserve this right only 
for the most severe crime, the threat of taking an innocent life or, in 
rare cases, property.  Is there a case where this might be extended to 
an "innocent server"? Perhaps one protecting your home network?  Credit 
card data?  Bank account?  A small number of servers that the whole 
Internet depends on?



From: Nicholas Weaver <nweaver@CS.berkeley.edu>
Subject: ONE case where vigilantism worked...

There actually is one case where vigilantism worked: the das-bistro 
anti-code-red-II default.ida script.

This script, when installed on a Web server, would respond to a Code 
Red II probe with a counterattack which disabled the Web server using 
the Code Red II installed backdoor and restarted the machine, clearing 
the Code Red II infection (memory resident) and preventing reinfection 
and machine abuse.

Considering that all those machines were broadcasting that they are 
trivially vulnerable, removing them from the net is probably necessary, 
especially since there ARE no police to call: there is no standard way 
to say "this machine is compromised" and get the ISP to do anything 
about it.

Someone malicious could have just as easily tweaked and released 
CRclean (a passive, sourcecode only "antiworm" published on BugTraq) 
with a malicious payload to co-opt all those machines.  Thus, having a 
small/medium number of anti-code-red-II Web pages was probably of benefit.

Of course, it only worked because of CRII's authors silliness and/or 
strategic stupidity (don't make control channels that can be used by 
anyone unauthorized, and close the hole you came in on).



From: "John.Deters" <John.Deters@target.com>
Subject: Counterattack

In your article, you claim that vigilantism is wrong, an idea that 
"society after society has eschewed."

You don't seem to take into account that the Internet is a brand-new 
*kind* of society.  For the first time in history, we have a society 
that is not tied to geography.  All legal systems were and are still 
tied to geopolitical boundaries.  But IP packets don't apply for visas 
before crossing those boundaries.  The wires and fibers carry goods, 
services, and mischief equally, and without prejudice.  So commerce 
occurs, regulated and taxed only by people naive enough to volunteer to 
their local governments that they deserve to be regulated or taxed for 
their online activities.  And mischief occurs too; but the mischief 
makers do not usually feel such compulsions to report their activities.

Also, the definition of mischief varies depending on where you 
stand.  The RIAA believes that mischief happens when a song is 
downloaded.  I believe that it happens when I get spam or some lame 
e-mail virus.  You believe it happens when your clients get DDOS attacked.

There is no global government regulating this Internet society.  A 
patchwork of geographically bound law enforcement agencies hunting down 
mischief makers is about all we have right now.  Sometimes they stop at 
their boundaries, sometimes they call their cohorts on the other side 
of the boundary to make an arrest on their behalf.  Most of the time 
they do nothing.

So in a basically lawless society, one that has not yet formed a 
cohesive government, one that allows a mischief maker to hide between 
governments, what would you have people doing when nobody can provide 
justice?  Should they do nothing?  Call the FBI?  Call for a Global 
Internet Government?

Vigilantes are not simply "taking the law into their own hands," 
because usually there is no law that can be applied.  So if a hacker 
goes after a spammer's computer, I'll cheer.  If the RIAA goes after a 
Napster user's computer, I don't really care.  I'll defend myself on 
the Internet, thank you very much.  But the one thing I am SURE I don't 
want to see is a global regulatory agency deciding whether or not they 
"approve" of the packets I'm sending.  Because I have no doubt that 
whatever I send or receive, be it music, pictures, or subversive e-mail 
to some crypto newsletter, some group will be offended and call for my 
arrest.



From: "Tousley, Scott W." <Scott.Tousley@anser.org>
Subject:  Department of Homeland Security

In the December 2002 Crypto-Gram, your comments on the Department of 
Homeland Security included:  "Security has two universal truisms 
relevant to this discussion.  One, security decisions need to be made 
as close to the problem as possible... Two, security analysis needs to 
happen as far away from the sources as possible."

I do not agree fully with the second truism, because security analysis 
of rare events must be both centralized and decentralized.  Security 
analysis is increasingly a distributed challenge that will continue to 
involve a judicious mixture of systems and people, and this analysis 
challenge requires a substantial amount of context that only comes with 
proximity.  We must somehow enable effective analysis from the national 
and international analysts all the way down to the ground-level 
security guard and first-line supervisor.  Cops and guards and 
first-responders can fight terrorism effectively only if they 
themselves are lightly steeped in and contribute to the larger analysis 
context.  The strength, flexibility and evolution of networks can 
support much of this need, if these still-embryonic networks are not 
squashed by bureaucratic interests of a national Homeland Security 
Department and various state and municipal counterparts fighting to 
feed at the trough.  I do worry that our reorganization will make 
security more brittle when we coordinate too heavily in the name of 
political, bureaucratic, and budgetary efficiency.



From: The Wengers <wenger@bigfoot.com>
Subject:  Department of Homeland Security

I agree with your assessment that analyzing intelligence should not be 
solely entrusted to the new Dept. of Homeland Security.  But I see some 
very disturbing signs that the balance has been tipped too far the 
other way in order to protect the turf of our existing intelligence 
agencies.

The tension is to create enough overlapping jurisdiction so that things 
don't fall through the cracks, but not so much as to create unnecessary 
redundancy and wasteful turf battles.  Therefore, I was disturbed to 
read a recent Washington Post article called "Homeland Security Won't 
Have Diet of Raw Intelligence Rules Being Drafted to Preclude 
Interagency Conflict" (by Dan Eggen and John Mintz, Dec. 6, 2002; page 
A43).  The article notes that "[f]or now, the intelligence agencies 
have persuaded the White House that information provided to the 
Homeland Security Department should be in the form of summary 
reports.  Those summaries generally will not include raw intelligence 
or details on where or how the information was gathered, in order to 
protect sources and methods."

It may not make sense to strip the existing intelligence agencies of 
their intelligence gathering and analysis roles for the reasons you 
gave.  However, if this Homeland Security Agency is to serve any vital 
role, it should be as a coordinator of threat analysis and 
response.  And I don't believe it can do that job in a meaningful way 
if it is required to rely solely on second-hand data.  As you aptly 
wrote "[a]ll these [intelligence] organizations have to communicate 
with each other, and that's the primary value of a Department of 
Homeland Security.  One organization needs to be a single point for 
coordination and analysis of terrorist threats and responses.  One 
organization needs to see the big picture, and make decisions and set 
policies based on it."  But how can the Homeland Security Director see 
the big picture and make fully informed decisions if his/her staff 
cannot review the data upon which the conclusions they are being fed 
are based?  This effort by the CIA, NSA and FBI to keep Homeland 
Security's snout out of the intelligence data trough cannot be a good sign.

The Washington Post article goes on to note that "Administration 
officials already are considering, for example, whether to include 
homeland security representatives as members of the 56 regional Joint 
Terrorism Task Forces, which oversee local terror investigations."  How 
could this be an item for debate?  If you look at the FBI's description 
of the JTTF program, it involves representatives of scads of federal 
agencies along with state and even local agencies.  "There are 
currently 36 JTTFs in operation, which reflects an increase of 25 task 
forces since 1996, to which more than 620 FBI special agents are 
assigned, and approximately 584 full-time and part-time officers from 
other federal, state, and local agencies are assigned.  Full-time 
federal participants in the JTTF program include the Immigration and 
Naturalization Service; U.S. Secret Service; Naval Criminal 
Investigative Service; U.S. Marshals Service; U.S. Customs Service; 
Bureau of Alcohol, Tobacco, and Firearms; U.S. Border Patrol; U.S. 
Department of State/Diplomatic Security Service; Postal Inspection 
Service; Internal Revenue Service; Department of Interior's Bureau of 
Land Management; Air Force Office of Special Investigations; U.S. Park 
Police; Federal Protective Service; Treasury Inspector General for Tax 
Administration; and the Defense Criminal Investigative Service." (Nov. 
13, 2001, Statement for the Record of Assistant Director Kathleen 
McChesney Training Division, FBI on Communication with the Law 
Enforcement Community Before the United States House of Representatives 
Committee on Government Reform Washington, D.C. 
<http://www.fbi.gov/congress/congress01/mcchesney111301.htm>)

Let me get this straight, the Park Police and the Bureau of Land 
Management are represented in the Joint Terrorism Task Forces but the 
Department of Homeland Security is not?   How can this be a good sign?


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