List:
I thought this was a good read (1st section). Take it as you will. At
minimum is great background into the CERTs advisory. This email was not
intended to start any discussions or debates, it is only passed on as
information regarding SNMP.
BTW This is an excellent news letter...and its FREE.
Jason Allison
Principal Engineer
ARINC Incorporated
Office: (410) 266-2006
FAX: (410) 573-3026
-----Original Message-----
From: Bruce Schneier [mailto:schneier@counterpane.com]
Sent: Friday, March 15, 2002 4:39 PM
To: crypto-gram@chaparraltree.com
Subject: CRYPTO-GRAM, March 15, 2002
CRYPTO-GRAM
March 15, 2002
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) 2002 by Counterpane Internet Security, Inc.
** *** ***** ******* *********** *************
In this issue:
SNMP Vulnerabilities
"Responsible Disclosure" IETF Document
Crypto-Gram Reprints
Terrorists, Cryptography, and Export Laws
News
Counterpane News
Bernstein's Factoring Breakthrough?
Richard Clarke on 9/11's Lessons
Comments from Readers
** *** ***** ******* *********** *************
SNMP Vulnerabilities
SNMP is the Simple Network Management Protocol, the most popular protocol
to manage network devices. Hundreds, possibly thousands, of products use
it. Last fall, a group of Finnish researchers discovered multiple
vulnerabilities in SNMP. By exploiting the vulnerabilities, an attacker
could cause a denial-of-service attack, and in some cases take over control
of the system.
The vulnerabilities concerns SNMP's trap-handling and request-handling
functions, and stem from problems in the reference code (probably) used
inside the Abstract Syntax Notation (ASN.1) and Basic Encoding Rules
(BER). The SNMP vulnerabilities affect hundreds of different devices:
operating systems, network equipment, software packages, even things like
digital cameras. It's a BIG deal.
It's actually a bigger deal than has been reported. ASN.1 is used inside a
lot of other applications, such as OpenSSL. These vulnerabilities aren't
limited to SNMPv1; that's just the only thing that's been well-publicized
at this point. (The recently reported problems in mod_ssl and Apache are
apparently related to this, too.)
The history of the vulnerability's discovery and publication is an
interesting story, and illustrates the tension between bug secrecy and full
disclosure. A research group from the Oulu University Secure Programming
Group in Oulu, Finland, first discovered this problem in October 2001, and
decided not to publish because it was such a large problem. CERT took on
the task of coordinating the fix with the major software vendors, and has
said that the reason publication was delayed so long is that there were so
many vendors to contact. CERT even had problems with vendors not taking
the problem seriously, and had to spend considerable effort to get the
right people to pay attention. Lesson #1: If bugs are secret, many vendors
won't bother patching their systems.
The vulnerability was published on 12 February. Supposedly, this was two
weeks earlier than planned, and because the story was leaking too
much. CERT felt that early publication was better than widespread
rumors. Some companies were caught off-guard. Even though they had months
to patch their systems, they weren't ready and needed those two extra
weeks. Some companies didn't bother to start worrying about the problem
until publication was imminent. Lesson #2: It is only the threat of
publication that makes many" vendors patch their systems. (To be fair,
many companies did a great job proactively patching their systems. And in
many cases, the patches were not trivial. Some vendors were swamped by the
sheer number of different products and releases they had to patch and
test. And I stress "test", because patching mature code carries a strong
probability of either not fixing the problem or of introducing new
problems.)
When CERT finally published and the Oulu Web site went live, there were all
sorts of reactions. Some tried to capitalize on the announcement to sell
their products; others tried to minimize it. Many vendors had no idea if
they were vulnerable or not But because publication included demonstration
code -- the PROTOS tool -- vendors and security companies were able to test
networks and equipment. Lesson #3: Publication must include enough
information to reproduce the vulnerability; otherwise, there's no way for
anyone to determine how serious the threat is. And Lesson #4: If there is
no way to independently verify the vulnerability, then organizations are
forced to rely on information from potentially biased sources.
As of this writing, there have been no credible reports of this
vulnerability being exploited in the wild. Counterpane's monitoring has
not detected any of our customers being attacked via this
vulnerability. This is not to say that no one has -- writing an attack
tool is a straightforward programming task -- but no one has published such
a tool and put it in the hands of the script kiddies. Lesson #5:
Publication does not automatically mean the vulnerability will be exploited.
So far we've been lucky. But a tool could show up at any time, so relying
on that luck would not be smart. And even though everyone has been urged
to patch their systems and products, some will not. Even if it takes
months before someone writes an attack tool, it will work against a
surprisingly large subset of systems. Lesson #6: Publication increases the
likelihood that a vulnerability will be exploited.
And there are a lot of systems for which patches will never be
available. Many router vendors have gone out of business in the last few
years, and not every mom-and-pop software company out there has the money
or clue to replace their hardware because their code has a problem. Lesson
#7: Since many, many systems will remain unpatched, this vulnerability will
pose a risk for years to come.
At Counterpane, we were able to make use of the public demonstration code
to quickly write filters for our Sentry and push them down to our
customers' networks. We did this within hours, so even if they didn't
patch their systems we could monitor them for evidence of exploitation. We
patched our own Sentry. This wasn't perfect -- in some systems the attack
didn't show up in their audit logs -- but it let us know which systems
would benefit from other security tools, like IDS signatures tuned to
detect the PROTOS tool. We collected and maintained a list of intrusion
detection signatures for Snort, RealSecure, CiscoIDS, Network Flight
Recorder, etc., that were specifically designed to collect the PROTOS'
tool's test packets.
We also sent out an advisory to our customers -- a voice of reason among
the slightly hysterical news articles -- and made our Network Intelligence
group available in a conference call to reassure them. We made our
research available to the FBI and other security organizations. Lesson #8:
Vigilant monitoring provides another layer of security, if and when
products and patches fail.
While these vulnerabilities are serious, the fact that SNMP is vulnerable
should not come as a surprise to anyone. Vulnerability "U7" in the SANS
Top 20 talks about SNMP. SANS's recommendation: "If you do not absolutely
require SNMP, disable it." This was good advice when the list was
released, and it's good advice now.
CERT advisory:
<http://www.cert.org/advisories/CA-2002-03.html>
<http://www.cert.org/tech_tips/snmp_faq.html>
Counterpane advisory:
<http://www.counterpane.com/alert-snmp.html>
Oulu's analysis and PROTOS test suite:
<http://www.ee.oulu.fi/research/ouspg/protos/testing/c06/snmpv1/>
Analyses and articles:
<http://techupdate.zdnet.com/techupdate/stories/main/0,14179,2847924,00.html
>
<http://www.theregister.co.uk/content/4/24167.html>
<http://www.infoworld.com/articles/op/xml/02/03/04/020304opsecurity.xml>
** *** ***** ******* *********** *************
"Responsible Disclosure" IETF Document
The so-called "Responsible Disclosure" IETF document has been released as a
draft. Despite some of the writings to the contrary, it is not a blueprint
for companies to keep their vulnerabilities secret. It's one view of how a
vulnerability should be released: first to the vendor and then, after a
reasonable amount of time has passed, to the general public.
In general, I agree with the philosophy of the document. I want vendors to
have time to prepare patches before vulnerabilities are made public. At
the same time, I don't want publication to be limited in any way. This
document attempts to strike a balance, and I think it does a good job.
My complaints are more about procedure than content. I don't think this
makes any sense as an IETF document. The IETF is a standards body; they're
good at specifications about which bits go where, but have no business
making political proposals.
I don't like the way the document is written: there are so many suggestions
and so few requirements that someone could do almost anything and then
claim to be following the document. And I believe the document could be
used by companies to justify withholding vulnerability information and
ignoring security problems. In my account of the SNMP vulnerability above,
you can see how the threat of full disclosure is what forced companies to
patch their systems. To the extent that following the IETF document
reduces that threat, it also reduces our security.
And I think the title is wrong. It's "Limited Disclosure," or maybe "Slow
Disclosure." Whether or not it is responsible is still a matter of debate.
I know there are several alternative proposals being drafted. I would like
to see some kind of single consensus document at the end of this process,
but I don't think the IETF is the place to reach that consensus.
Draft Document
<http://www.ietf.org/internet-drafts/draft-christey-wysopal-vuln-disclosure-
00.txt>
<http://zdnet.com.com/2100-1105-842656.html>
<http://www.computerworld.com/storyba/0,4125,NAV47_STO68558,00.html>
<http://www.eweek.com/article/0,3658,s=712&a=23200,00.asp>
** *** ***** ******* *********** *************
Crypto-Gram Reprints
Security patch treadmill:
<http://www.counterpane.com/crypto-gram-0103.html#1>
Insurance and the future of network security:
<http://www.counterpane.com/crypto-gram-0103.html#3>
The "death" of IDSs:
<http://www.counterpane.com/crypto-gram-0103.html#9>
802.11 security:
<http://www.counterpane.com/crypto-gram-0103.html#10>
Software complexity and security:
<http://www.counterpane.com/crypto-gram-0003.html#SoftwareComplexityandSecur
ity>
Why the worst cryptography is in systems that pass initial cryptanalysis:
<http://www.counterpane.com/crypto-gram-9903.html#initial>
** *** ***** ******* *********** *************
Terrorists, Cryptography, and Export Laws
For years, we cryptographers have been saying that limiting export of
cryptography to 40 bits is ineffectual, because terrorists aren't stupid
enough to use broken 40-bit keys. So, imagine my surprise when we learn
that a terrorist is stupid enough to use 40-bit keys.
Turns out that the Richard Reid, the inept shoe-bomber terrorist, encrypted
his PC files using 40-bit keys. And they were brute forced.
It's easy to misinterpret this. The lesson here is not that all terrorists
are stupid, only that there exists at least one stupid terrorist. Despite
this deliciously ironic anecdote, the benefits to society of ubiquitous
strong encryption outweigh the disadvantages of not being able to decrypt
the hard drives of captured terrorists.
<http://www.newscientist.com/news/news.jsp?id=ns99991804>
<http://news.independent.co.uk/world/americas/story.jsp?story=114885>
<http://slashdot.org/articles/02/01/18/146229.shtml>
** *** ***** ******* *********** *************
News
A DoD study shows that face scanning only works about 50% of the time under
the best conditions:
<http://www.wired.com/news/politics/0,1283,50470,00.html>
EPIC's National ID Card resource page:
<http://www.epic.org/privacy/id_cards/>
Internet eavesdropping on a massive scale. Turns out that Comcast has been
secretly recording the surfing habits -- every Web page visited -- of its
million high-speed customers. They're doing this for performance purposes,
but this data would be available to police and the FBI with a court order,
and to lawyers in civil lawsuits.
<http://www.siliconvalley.com/mld/siliconvalley/2661735.htm>
At least one Congressman, Rep Markey, wants to make this practice illegal:
<http://www.usatoday.com/life/cyber/tech/2002/02/13/comcast-privacy.htm>
A couple of days after this news story broke, Comcast said they would no
longer do this:
<http://www.nytimes.com/2002/02/14/technology/14PRIV.html>
Good story on the security risks of the SOAP protocol:
<http://www.prescod.net/rest/security.html>
Security holes in the anonymous Web-surfing program SafeWeb:
<http://www.wired.com/news/politics/0,1283,50371,00.html>
<http://www.theregister.co.uk/content/6/24105.html>
<http://www.cs.bu.edu/techreports/pdf/2002-003-deanonymizing-safeweb.pdf>
Interesting story about airplane security. Air marshals took control of a
plane bound for Salt Lake City, and one skeptical passenger didn't believe
them. How do you verify credentials in a situation like this?
<http://www.salon.com/people/feature/2002/02/20/bizzaro/index.html>
Outsourcing security: dos, don'ts, and advice
<http://www.networknews.co.uk/Analysis/1129412>
Nice essay on the full disclosure debate:
<http://www.infosecnews.com/opinion/2002/02/27_02.htm>
Scarfo pleads guilty, so there'll be no appellate court consideration of
the FBI's key logger and its warrant requirements.
<http://story.news.yahoo.com/news?tmpl=story&u=/ap/20020228/ap_on_re_us/mobs
ter_s_son_2>
Interesting Macintosh vulnerability. These are cascades of fairly
innocuous features that combine to cause problems.
<http://homepage.mac.com/vm_converter/mac_autoexec_vuln.html>
Good article on investigative techniques, and problems, for solving
cybercrimes.
<http://www.osopinion.com/perl/story/16502.html>
An Oracle study concludes that insiders are worse than hackers. This
should be no surprise.
<http://www.networknews.co.uk/News/1129574>
<http://www.theregus.com/content/55/24212.html>
<http://oraclepressoffice.bulletonline.com/showrelease.php?id=128>
Latest bogus security challenge. Too stupid for even the Doghouse:
<http://biz.yahoo.com/bw/020301/12094_1.html>
Excellent (and long) paper on a risk-management approach to computer
security:
<http://cisac.stanford.edu/docs/soohoo.pdf>
Microsoft is delaying .NET, citing security concerns as one of the
reasons. Assuming this is a real reason, and not an invented reason for
the press, this is good news. Possibly it's even a harbinger of a new way
of doing business in Redmond.
<http://www.pcmag.com/article/0,2997,s=1582%26a=23449,00.asp>
I'm still skeptical, but hopeful.
<http://news.zdnet.co.uk/story/0,,t269-s2105503,00.html>
Two different papers on optical information leakage, one from CRT displays
and the other from LEDs. Information can be read at a distance, without
physical contact to the target display. This kind of thing is analogous to
electrical emanations, aka TEMPEST.
<http://www.cl.cam.ac.uk/~mgk25/ieee02-optical.pdf>
<http://applied-math.org/optical_tempest.pdf>
Several reporters have asked me how big a deal I thought this is. Short
answer: not very. I have no way of defending myself against attackers this
well motivated and this well funded. They can already park a van outside
my house and eavesdrop on my computer. They can already break into my
house when I'm away and install dozens of listening devices and keyboard
monitors and who-knows-what-have-you. So, now they have another way they
can eavesdrop on me. I still can't do anything about any of them. At
least, not without spending a WHOLE lot of money.
Network Associates has killed PGP:
<http://www.zdnet.com/anchordesk/stories/story/0,10738,2852437,00.html>
<http://www.computerworld.com/storyba/0,4125,NAV47_STO68885,00.html>
This doesn't mean that PGP is dead, mind you. The OpenPGP standard, and
GPG, are still going strong.
<http://www.theregister.co.uk/content/54/24336.html>
<http://www.openpgp.org/>
A really clever social-engineering hack. Nothing to do with computers, but
well worth reading.
<http://seattletimes.nwsource.com/html/localnews/134416347_scam07m.html>
Excellent paper on software liabilities, written by a couple of attorneys
and someone from CERT. Required reading.
<http://www.cert.org/archive/pdf/Downstream_Liability.pdf>
** *** ***** ******* *********** *************
Counterpane News
Schneier will be presenting Counterpane's Managed Security Monitoring
service in the following cities: Austin, Boston, Dallas, Chicago,
Minneapolis, New York, and Tallahassee. Visit this page to see dates, and
to sign up:
<http://www.counterpane.com/seminars.html>
There are several new case studies from Counterpane customers here:
<http://www.counterpane.com/experiences.html>
Assorted Counterpane partner/customer press releases:
<http://www.counterpane.com/pr-neccisco.html>
<http://www.counterpane.com/pr-dyntek.html>
** *** ***** ******* *********** *************
Bernstein's Factoring Breakthrough?
Last fall, mathematician Dan Bernstein circulated a paper discussing
improvements in integer factorization, using specialized parallel
hardware. The paper didn't get much attention until recently, when
discussions sprang up on SlashDot and other Internet forums about the
results. A naive read of the paper implies that factoring is now
significantly easier using the machine described in the paper, and that
keys as long as 2048 bits can now be broken.
This is not the case. The improvements described in Bernstein's paper are
unlikely to produce the claimed speed improvements for practically useful
numbers.
Currently the fastest factoring algorithm is the Number Field Sieve (NFS),
which supplanted the Quadratic Sieve several years ago. Basically, the NFS
has two phases. The first is a search for equations that satisfy certain
mathematical properties. This step is highly parallelizable, and today is
routinely done with thousands of computers. The second step is a large
matrix calculation, which eventually produces the prime factors of the
target number.
Bernstein attempts to improve the efficiency of both steps. There are some
good observations here that will result in some minor speedups in
factoring, but the enormous improvements claimed are more a result of
redefining efficiency than anything else. Bernstein positions his results
as an effect of massive parallization. To me, this is misleading. You can
always simulate a parallel machine on a single computer by using a
time-sliced architecture. In his model, the "cost" of factoring is a
product of time and space, and he claims that he can reduce the cost of
parallel sorting from a factor of m^4 to m^3. Bernstein justifies his
assumptions by claiming that a single processor needs m^2 memory, whereas
an array of m^2 processors only needs constant memory. This may be true,
but neglects to factor in the cost associated with connecting those
processors: tying a million simple processors together is much more
expensive than using a single processor of the same design with a mi
llion bits of memory. Again, it is not clear that this technique will buy
you anything for practical sized numbers.
To be sure, Bernstein does not say anything different. (In fact, I commend
him for not being part of the hyperbole.) His result is asymptotic. This
means that it is eventually true, as the size of the number factored
approaches infinity. This says nothing about how much more efficient
Bernstein's algorithm is, or even whether or not it is more efficient than
current techniques. Bernstein himself says this in one of his
posts: "Protecting against [these techniques] means switching from n-bit
keys to f(n)-bit keys. I'd like to emphasize that, at this point, very
little is known about the function f. It's clear that f(n) is
approximately (3.009...)n for *very* large sizes n, but I don't know
whether f(n) is larger than n for *useful* sizes n." What he means is: at
some bit length these techniques will be useful, but we have no idea what
that bit length is.
I don't believe in the factor of n - 3n length improvement. Any practical
implementation of these techniques depends heavily on complicated
technological assumptions and tradeoffs. Parallel computing is much easier
to say than it is to do, and there are always hidden complexities. I think
when all the math is said and done, these other complexities will even out
his enhancements.
This is not to belittle Bernstein's work. This is good research. I like
his novel way of using sorting techniques to carry out the linear algebra
part. This might be useful in a variety of other contexts, and is likely
to open up new research directions in the design of more efficient sorting
networks and sparse matrix algorithms. There are other speed improvements
to the NFS in this paper, and they will most definitely be researched
further.
Over the past several decades factoring has steadily gotten easier, and
it's gotten easier faster than anyone would have believed. Speed
improvements have come from four sources. One, processors have gotten
faster. Two, processors have gotten cheaper and easier to network in
parallel computations. Three, there have been steady flows of minor
improvements to the factoring algorithms. And four, there have been
fundamental advances in the mathematics of factoring.
I believe that Bernstein's work falls under the third category, and takes
advantage of ancillary improvements in the second category. And if history
is any guide, it will be years before anyone knows exactly whether, and
how, this work will affect the actual factoring of practical numbers.
Bernstein Paper:
<http://cr.yp.to/papers/nfscircuit.ps>
** *** ***** ******* *********** *************
Richard Clarke on 9/11's Lessons
At this year's RSA Conference, Richard Clarke gave the keynote address on
cybersecurity in the aftermath of September 11th. The beginning of his
talk was excellent: he listed six lessons of the terrorist attacks. It
started falling apart when he states that businesses should, out of the
goodness of their hearts and concern for their way of life, produce and use
more secure products. And it collapsed further when he advocated a new
exemption to the Freedom of Information Act that everyone who studies the
issue claims is unnecessary and harmful. But his opening was good.
Here are Clarke's six lessons. They don't just apply to combating
cyber-terrorism, and I will explain them in terms of everyday network
security.
1. "We have enemies." Everyone does. Companies have competitors. People
have others who don't like them. Some enemies target us by name, others
simply want to rob someone and don't care whom. Too many organizations
justify their inattention to security by saying: "Who would want to attack
us?" That just doesn't make sense.
2. "Don't underestimate them." Don't. Whether it is a DVD pirate living
in a country with no copyright laws, or a hacker kid who spends days trying
to break into a network, cyberspace attackers have proven to be better
funded, smarter, and more tenacious than anyone has estimated. If you
assume that your enemies won't be able to figure out your defenses and
bypass them, you're not paying attention.
3. "They will use our technology against us." This is especially true in
cyberspace. Almost all attacks involve using the very network being
attacked. Maybe it's a vulnerability in the software; maybe it's a feature
that should never have been created. Hacking is judo: using network
software to do things it was never intended to do.
4. "They will attack the seams of our technology." As bad as most
cryptography is out there, it's almost always easier to break a system by
some other method. Attacks on the seams -- the places where different
technologies come together -- are more fruitful. Think of the FBI reading
PGP-encrypted mail by installing a keyboard sniffer, or people who bypass
copy-protection controls by mimicking them rather than breaking them. This
lesson is obvious to anyone who has broken security software.
5. "Our technology is surprisingly interdependent." That's certainly
clear. We've seen vulnerabilities in IIS affect all sorts of
systems. We've seen malicious code use features of Microsoft Word and
Outlook to spread. A single SNMP vulnerability affects hundreds of
products. Interdependence is how the Internet works. It's also how it
fails.
6. "The only way to solve this problem is for government and industry to
work together." This is more subjective, but I agree with it. I don't
think that industry can do it alone, mostly because they have no incentive
to do it. I don't think that government can do it alone, because they
don't have the capability. Clarke seems to think that it's government's
job to provide some funding, high-level coordination, and general
cheerleading. I think it's government's job to provide a financial
incentive to business. If you want to fix network security, hack the
business model. Remove the liability exemptions from software. Demand
regular reporting similar to what was required for Y2K. Make the CEO care.
Clarke spends a lot of time visiting companies and talking to them about
security. I'm sure the CEOs give him a warm reception, and tell him that
they'll make their stuff more secure. But what happens a month later, when
budgets are tight and a release date looms? Will the CEO remember his
promise to Clarke, or will he listen to the demands of the market? If the
government really wants the CEO to care, it's going to have to make
security a market force.
I don't see any other way.
** *** ***** ******* *********** *************
Comments from Readers
From: "Douglas St.Clair" <dwstclair@tellink.net>
Subject: RE: CRYPTO-GRAM, February 15, 2002
I taught the course in Systems Safety Analysis at Picatinny Arsenal to
nuclear, biological, chemical, and conventional weapons designers in the
late 1960s. There are two points I want to make based on this experience.
First, the distinction between safety and reliability is based on time and
place, not the design. For example, consider a faulty door on a manned
NASA vehicle. If the door falls off while the vehicle is being moved to
the launch site, it is unreliable. If the door fails in space and men die,
then it is an unsafe door.
Now consider how things get designed. Let's consider weapons systems
because, for one reason, it gets us away from the love/hate Microsoft
issues. Somebody wants to put a missile on a Humvee. The safety guy wants
at least two switches be thrown before the missile fires and he wants them
placed so it takes two men to do it at the same time. The reliability guy
wants switches all over the vehicle so that if one of them is thrown the
little rascal is underway. Both guys can argue reasonably for their
position. In the end, since they can't agree, some manager who may not
understand the technical issues will make a decision.
I think that the issue also revolves around the genetic makeup of the
players. The ideal safety guy measures risk in terms of the magnitude of
regret. The ideal reliability guy considers magnitude of risk. If the
risk is less than some limit he will accept it. Managers are encouraged to
make decisions, in the absence of good data, no matter what the risk. I
think these traits are coded in the genes of the principals.
Before any substantial change can be made in Microsoft, the company's
culture needs to change and that means the players will need to change
too. I don't see Microsoft firing and hiring the substantial number of
people required to make a change in culture possible. In the end, Barne's
Law, "If nothing changes, everything will remain the same," will win out.
From: "Mike Mathison" <MikeMathison@btinternet.com>
Subject: RE: Judging Microsoft
Forgive me, I'm not a security expert, but I can't help summarizing some of
your advice on how we are to gauge Microsoft's progress towards security
salvation as follows:
* The less useful Microsoft makes its products and the more features it
removes from them the more virtuous it becomes.
* The more difficult Microsoft makes its products to use and configure
(lots of switch-able options and add-ins) the more virtuous it becomes.
* The more Microsoft abandons its new key strategic technology direction
(universal Web services over ubiquitous HTTP with smart universal clients)
the more virtuous it becomes.
If I were Microsoft, I would conclude that if you are correct and they
really have to do all of this, then they are doomed, and so I guess I would
instead be hoping that you are wrong (or at least a little overzealous in
your triumph at their admission of sin).
Incidentally, I do sometimes wonder if some of the computer security
industry _really_ wants Microsoft to sort out its problems or is just
paying lip service and having a good time whining. Let's not forget there
was a time when Microsoft neither knew nor cared very much about the
Internet. Those were the days when Netscape was verging on a browser
monopoly and you needed to know or pay someone with a degree in electronic
engineering to set up a dialup connection on a PC. No one argues that Bill
Gates was wrong to change his company's direction then, and although it was
late in the day he did succeed, despite widespread skepticism. He's
neither stupid nor lazy (there, I said it).
From: Mark Reynolds <mark@aoainc.com>
Subject: CRYPTO-GRAM Feb 15, 2002: Comment
In the most recent issue of CRYPTO-GRAM, in the article "Judging
Microsoft," it is stated that "Originally, e-mail was text only, and e-mail
viruses were impossible," as part of the discussion on recommended security
improvements. While the first part of this statement is definitely
accurate, I would disagree with the second part.
Even very early Unix(tm) systems had the ability to define a "virtual" user
that was actually an alias to the standard input of a program. Thus, an
entry such as
print "| /usr/bin/lpr"
in the aliases file would cause all e-mail sent to "print" to be sent to
the stdin of /usr/bin/lpr. It was not uncommon for people to attempt, and
occasionally succeed, in creating a specially formatted text-only e-mail
that would exploit a vulnerability in the destination program. The fact
that e-mail at that time was not really 8-bit clean only added to the
challenge.
While this was not strictly speaking a virus, it was certainly a security
vulnerability, and given the ability to exploit buffer overflows in lpr,
for example, it is not a huge leap to imagine a self-propagating e-mail
message that would be able to infect any site that defined such a
well-known alias, and that also had a network connection. I do not know if
this was ever actually done back then, but it was certainly made possible
as soon as the ability to have piped (|) output in an e-mail alias was
added.
From: "Andrew van der Stock" <ajv@greebo.net>
Subject: Factual Mistakes in Microsoft Analysis
The central thesis of the paper is correct, and the suggestions for
improvement worthy, but some of the facts are simply wrong, and need to be
rectified.
"...too many Microsoft server components run as Administrator" -- most
services as shipped from MS use LOCALSYSTEM, not
"Administrator." LOCALSYSTEM is far more privileged than Administrator,
except that it cannot use SMB-based networking -- unless it implements its
own SMB stack. The risk of using LOCALSYSTEM is somewhat worse than
running as Administrator as it can act as part of the operating
system. The .NET CLR runs as MACHINE, an analogous account to LOCALSYSTEM,
but with few privileges.
"Microsoft should drop the code-signing security paradigm in favor of the
sandbox paradigm." No, this is called defense in depth. Both code signing
and sandbox paradigm (such as Java or .NET's CLR model) should be
implemented and used. ActiveX as it stands today is un-securable, and
should be disabled by default unless a user explicitly requires its
services.
"Too much of it functions without leaving audit records of what
happened." This is wrong, and demonstrates beyond reasonable doubt the
authors' lack of experience with the platform they are slagging off. Use
Event Viewer. You'd be surprised how much stuff is in there, even by
default. Everything that the Object Manager grants access to (which is
everything) is auditable, you just need the right tool to turn on auditing
if it doesn't already have a GUI to do so. The MS BackOffice products
produce large quantities of very visible and useful logging. Just because
it isn't syslog doesn't mean it doesn't exist.
Here's a picture of my machine giving adequate information about how it is
running. I could have chosen any one of the other 418 events in this log,
or the 1910 events in the System event log, or the 893 events in the
security event log (which are pure auditing in the TCB sense).
<http://www.evilsecurity.com/eventvwr.jpg>
"Microsoft should drop all plans for automatic software updates via the
Internet until they can be done securely and reliably." The risk of all
those machines out there on the Internet without any updates at all, far
outweighs the risks of individual machine death. And for the vast, vast
majority of all users, the updates work as planned. Sure, when things go
wrong, it's painful for the individual, but the pain suffered by the whole
is much less. The authors obviously have a libertarian bias, and should
acknowledge that the Internet is a commons to be shared. The only way to
share a commons is to minimize the risk from bad elements. If this means
individuals assuming greater risk for a resource they own, so be it. I'd
rather be on a network where there aren't thousands of zombies waiting to
attack me because of insecurities caused by a vendor. Let them fix the
mess in the best way they can. Most end users (think of your mum) can't
manage this process (through learned help
lessness more than anything else), and in some ways from a human-computer
interface and fair trading laws point of view, they shouldn't have
to. Like a tire recall -- it's your responsibility to show up at the
dealer, and then it's the dealer's responsibility to swap the faulty parts
out. End of story for *consumers*. Corporates already block Windows
Update through group policy, or simply by not letting their users log on as
Administrator-level accounts.
"We would also like to see Microsoft abandon the Registry in favor of a
less opaque and more user-friendly system." No, I don't think so. The
authors offer no replacement, but there's only one other mainstream
alternative: /etc. Don't make me laugh! The fundamentals of a single
remotely administratable place for settings are vital for large scale
deployments. There are increased risks for remote registry attacks, but
the other issues like undocumented settings, etc. (which are valid
complaints) can be addressed by the authors of programs -- if they choose
to make the registry settings (or file format) known, then great. The
registry is not end-user-friendly for a very simple reason: there's no
valid reason for people to go there.
It's like the ECU in your car, sure there's some fun to be had if you know
exactly what you're doing with someone else's software, but there's much
damage to be done if you have no clue. And most of MS's users are
completely unaware that the registry exists. The trick is for security
professionals like us to manage the risk of managing settings database or
files. And they aren't the only vendor to suffer from poor QA in this
area: fire up a stock RH 7.2 box and use vipw -- /etc/shadow becomes world
readable. Permissions are problematic the world over.
From: Adam Shostack <adam@zeroknowledge.com>
Subject: Re: Rebuttal to our Microsoft Article
Andrew van der Stock makes a number of good points in the above
comment. One of the challenges in writing an article as we did is the
difficulty of balancing a high level approach with never talking about
details. For example, his comments about localsystem are correct, but how
important is this? The reality is that too many services run with too much
privilege. Our argument for less privilege is not weakened by the details
of localsystem vs. administrator. These services should run as a user
explicitly tagged as "daemon subject to attack," and appropriately
restricted.
Regarding code-signing of all ActiveX code, we simply don't agree. Code
signing from arbitrary providers of code requires a lot of PKI effort for
little return. Bruce's previous comments in Crypto-Gram about SSL and its
PKI come to mind; who cares if the code you have is signed by someone
you've never heard of? (Signed updates from a vendor whose code you
already run is another matter.)
Regarding logging, once again we have a level problem. It is challenging
to make a Windows system log to a remote device. (There are now excellent
programs available that do this, and there is an issue of how much
Microsoft should provide vs. letting the market step in.) And while syslog
is insecure and unreliable, it at least makes it easy to send the
information to another system, where it can't be altered by malicious
code. We could have talked about this, and Andrew's provision of details
is certainly useful in reminding us the risks of such an essay. However,
each paragraph was cut fairly mercilessly of technical details, and that
led to some statements that are easy to misinterpret.
Andrew doesn't mention that we also made some mistakes in our discussion of
the SOAP protocol, which uses HTTP as one of its many transports. Again,
this was a matter of trying both to keep our comments at a high level and
to touch on some details, and we messed up.
From: "John.Deters" <John.Deters@target.com>
Subject: Microsoft and Security
You freely offer Microsoft a laundry list of top-level fixes that could
help restore security. The following link illustrates Microsoft's current
lack of commitment to security better than any other example I've seen.
<http://support.microsoft.com/default.aspx?scid=kb;en-us;Q228990>
The problem includes a list of 28 games that may hang when you try to play
them. The relevant message is found in this "solution":
>To resolve this issue, do one of the following:
>
>If you are using Windows NT, Windows 2000, or Windows XP please
>log off the computer, and then log on to the computer as a user
>with Administrator rights.
So according to Microsoft, BY DESIGN I must be an admin to play Train
Simulator (or any of the 28 games listed at the above URL.) All these
games have associated Web sites, and indeed have URLs in the code that
encourage you to "click here to visit the Microsoft Web site" for various
reasons. So even if you tried HARD to be safe, you are still likely to
fire up IE and hit the Web as an administrator.
Why should a game require a player to be an administrator? Who could
possibly have manufactured a larger security hole?
From: Scott and Karleen James <smjkkj@attbi.com>
Subject: Liability
As I read the pros and cons for software liability, I have to stop and
think about how other industries have to deal with product production and
reliability issues. I am not specifically trained in the security area but
I have been in the real business world long enough to make what I hope are
some valid observations.
I worked in the software industry. We sold newspaper publishing
software. Effects of coding errors ranged from minor to
catastrophic. Minor issues like text not being drawn in exactly the
correct location often had simple work-arounds or were handled in the next
upgrade of the software system. Catastrophic issues usually involved
putting someone on-site. These were situations where the database
contained garbage, or no usable film was being produced. Newspaper people
get really anxious when their software can't reliably produce output so
that they can publish a paper everyday. They can't just change software
like one would trade in a used car for a newer or different model. In any
case, there seems to be relatively little danger to me personally for
careless coding except that I might possibly lose my job if I screw up too
often. Often I was at the mercy of code written by someone else, patched
or improved by yet another person and now suspect or broken as a result of
a change made in a module elsewhere in the several hundred thousand lines
of code that made up our server/client system. A major problem could
easily mean the loss of thousands of dollars of revenue, so ignoring the
problem was never a choice.
I also worked at the Johnson Space Center. I am quite aware of what
Mission Critical software implies. In the world of NASA software, a major
problem can put millions of dollars and people's lives at risk.
Now for a different perspective, my wife works for a large petroleum
refining company. She works in the health, safety, security and
environment areas. I'd like to draw a comparison. If you have 10
programmers and nine of them are religiously following good design and
coding practices for creating secure, reliable software but one of them
isn't, what do you get? Clearly, the effects change depending on what
areas the shoddy coder touches. Overall, though, I would expect a pretty
good product. In the refining industry, if one guy in the facility doesn't
follow procedures, he puts EVERYONE at risk. I realize my analogy is not a
perfect one, but it gets one thinking in the right direction.
The thing that will really improve software is when someone figures out how
to establish a [more] direct link between the risks of using a product and
the creation of the product. The software industry seems to think the
tobacco industry business model is a good one. It's okay to kill your
customers, there will always be a new one to replace the one you just
lost. When an individual programmer associates the risks in using a
product with the choices made during design and coding, then quality,
security, and reliability will jump up dramatically. In my view, it seems
like it is the corporate entity that takes the blame for the substandard
work, not Frank or Bob or George or whoever.
If more programmers treated the software like a skyscraper in which they
lived on the top most floor, I'll bet they would be pretty keen on having a
good foundation (design) and they would choose quality materials and
skilled workers for construction (coding and testing). Having the building
collapse with them in it is not a risk they want to take. Why should
software be so different? When I wrote or modified code, I left my
signature in the file because I was proud of my work. If there was
something wrong with my work, I wanted to fix it.
A final thought: ever wonder how much "programmer burnout" contributes to
faulty software? Consider how long it takes to design, code, test, and
release a software title. If there is high turnover in the skilled labor
pool, what effect might that have on the product?
From: Marc Mutz <mutz@kde.org>
Subject: Software Liability
Your last issue of Crypto-Gram was full of reader's comments as well as
essays from you and others on why software companies should be held liable
for bugs in their products.
Despite all that hype for making companies liable for bugs and security
vulnerabilities in their products, there's one thing I'd like to remind
everyone of:
If software companies were liable when their products broke, Open Source
programmers would be much more hesitant to release their work to the
public. The GPL explicitly denies all such claims against the authors of
software released under that license.
I'd be more that hesitant to work on OpenPGP-related code in KDE if I could
be held liable for bugs, since a large-scale lawsuit against me would ruin
my life, thank you.
So, in the end we'd probably see a decrease in Open Source software
deployment (since nobody's there to get money back from) and an increase in
proprietary software deployment (since large companies have much money that
can be pressed from them for buggy software, much like the tobacco industry
is drained currently).
From: Mary Ann Davidson <Mary.Ann.Davidson@oracle.com>
Subject: Oracle's 14 Security Evaluations
In the February 15 Crypto-Gram that you say Oracle does not actually have
14 independent evaluations.
The ads do say 14 independent evaluations. It is true that we have
evaluated different versions of server products against the same criteria,
because prior to the Common Criteria we had to do country-specific
evaluations (US TCSEC or Orange Book, UK TCSEC and the occasional Russian
Criteria evaluation). The UK would not accept US evaluations, for
example. Happily, the Common Criteria (ISO-15408) is now recognized by
multiple countries as the de facto evaluation standard, which means we only
do Common Criteria evaluations plus the occasional FIPS-140 to validate
cryptographic modules.
However, we have indeed completed 14 of these independent
evaluations. Each evaluation is separate and distinct. It is not as if
one pays the fee and gets a certificate in the mail.
We remain committed to evaluations: Oracle Label Security is in evaluation
at EAL4, and we will be evaluating Oracle9i Database release 2 and Oracle9i
Label Security release 2 at EAL4, as well as submitting Oracle9i
Application Server for a FIPS-140 evaluation.
I would also note that the US Federal government requires independent
measures of assurance. National Security Telecommunications Information
Systems Security Policy (NSTISSP) #11, which goes into full effect in July
2002, requires any system involved in national security to have independent
measures of assurance (i.e., a security evaluation). In a post 9/11
world, there will be few waivers granted for this, and rightly so. I would
hope that you would see the merit of someone other than a vendor attesting
to their security claims. Apparently, the U.S. government and other
governments do.
For our server products, security evaluations represent about $1,000,000
apiece in additional security QA by someone other than Oracle. The larger
benefit is that one has to change development processes to get through an
evaluation, as the security of the development environment is part of what
is assessed. Unlike other vendors, we did not feel compelled to have a
new-found "security initiative," because our development processes were
altered over 10 years ago as part of the evaluation process. We are, as it
happens, extending our security development process across the rest of the
stack. When the marketing campaign is done, we will still be committed to
assurance, and a secure product lifecycle for every product in our
stack. I can also assure you that we use security flaws as an opportunity
for process improvement -- we are continually revising our coding standards
and release checklists based on new information and threats (and that
includes flaws that we or other research
ers find in our products).
Security people cannot have it both ways. The criticism is that "no
product is truly unbreakable" but perhaps the criticism ought to be "why
don't more vendors draw a line in the sand and commit to bulletproof
software, and commit to comply with relevant standards on 'what you means
when you say you are secure?'" Is the glass half-empty or half-full? I am
also aware that your firm focuses on assuming that there is no unbreakable
software and monitoring for attacks accordingly. Surely there can be room
for both in order to raise the security bar. Would you advocate no
independent measures of assurance because even evaluations are not
perfect? If I tell customers that unbreakable software is too hard, and we
give up, it may indeed give your firm and others like it an increasing
market, but it will be abdicating the responsibility that vendors MUST
assume for their own product security. I agree with you that the hard
stuff in security is very hard, but giving up because securi
ty is too hard is inexcusable. Too many have given up already.
From: Anonymous
Subject: Cloud Nine ISP
> Here's an example of a hack causing a company to go out of
> business. Cloud Nine, a UK ISP, ceased operations this week
> after being the victim of a DOS attack. The network needed
> to be rebuilt as a result of the attack, and the company's
> insurance wouldn't cover the repairs.
I must admit to being disappointed to read this in your newsletter. Go
back to those two URLs at <www.ispreview.co.uk>. I guarantee your Snake
Oil alarms will go off.
"We tried overnight to bring our Web servers back online but were seeing
denial of service attacks against all our key servers, including email and
DNS. These were of an extremely widespread nature.
"We felt we had a moral duty not to expose our customers to possible
attacks as well."
Since when was taking your customers' Internet connectivity away better for
them than a denial-of-service attack?
Searching <www.theregister.co.uk> comes up with a snippet of their initial
statement:
"First a firewall password brute force attack resulting in successful hash
and destruction of the firewall"
Hash? If I remember correctly this attack was meant to have been bounced
from a Web server, but it seems those comments have had to be taken offline:
<http://web.archive.org/web/20020215145613/http://www.ispreview.co.uk/cgi-bi
n/ispnews/viewnews.cgi?newsid1011958010,63027,>
To bathe in Snake Oil see:
<http://www.ispreview.co.uk/cgi-bin/ubb2/ultimatebb.cgi?ubb=get_topic&f=25&t
=000117>
From: Nathan Neulinger <nneul@umr.edu>
Subject: noticed something in Applied Cryptography
Happened to be re-reading Applied Cryptography, 2nd Edition, and noticed
something creepy on p.99 in "The Politics of Key Escrow," 3rd paragraph.
"Imagine a major terrorist attack in New York; what sorts of limits on the
police would be thrown aside in the aftermath?"
Just thought it was rather scary how right you can be without even
realizing it.
** *** ***** ******* *********** *************
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Please feel free to forward CRYPTO-GRAM to colleagues and friends who will
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CRYPTO-GRAM is written by Bruce Schneier. Schneier is founder and CTO of
Counterpane Internet Security Inc., the author of "Secrets and Lies" and
"Applied Cryptography," and an inventor of the Blowfish, Twofish, and
Yarrow algorithms. He is a member of the Advisory Board of the Electronic
Privacy Information Center (EPIC). He is a frequent writer and lecturer on
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Counterpane Internet Security, Inc. is the world leader in Managed Security
Monitoring. Counterpane's expert security analysts protect networks for
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Copyright (c) 2002 by Counterpane Internet Security, Inc.
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