Entries Tagged "trust"

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Trusted Computing Best Practices

The Trusted Computing Group (TCG) is an industry consortium that is trying to build more secure computers. They have a lot of members, although the board of directors consists of Microsoft, Sony, AMD, Intel, IBM, SUN, HP, and two smaller companies who are voted on in a rotating basis.

The basic idea is that you build a computer from the ground up securely, with a core hardware “root of trust” called a Trusted Platform Module (TPM). Applications can run securely on the computer, can communicate with other applications and their owners securely, and can be sure that no untrusted applications have access to their data or code.

This sounds great, but it’s a double-edged sword. The same system that prevents worms and viruses from running on your computer might also stop you from using any legitimate software that your hardware or operating system vendor simply doesn’t like. The same system that protects spyware from accessing your data files might also stop you from copying audio and video files. The same system that ensures that all the patches you download are legitimate might also prevent you from, well, doing pretty much anything.

(Ross Anderson has an excellent FAQ on the topic. I wrote about it back when Microsoft called it Palladium.)

In May, the Trusted Computing Group published a best practices document: “Design, Implementation, and Usage Principles for TPM-Based Platforms.” Written for users and implementers of TCG technology, the document tries to draw a line between good uses and bad uses of this technology.

The principles that TCG believes underlie the effective, useful, and acceptable design, implementation, and use of TCG technologies are the following:

  • Security: TCG-enabled components should achieve controlled access to designated critical secured data and should reliably measure and report the system’s security properties. The reporting mechanism should be fully under the owner’s control.
  • Privacy: TCG-enabled components should be designed and implemented with privacy in mind and adhere to the letter and spirit of all relevant guidelines, laws, and regulations. This includes, but is not limited to, the OECD Guidelines, the Fair Information Practices, and the European Union Data Protection Directive (95/46/EC).
  • Interoperability: Implementations and deployments of TCG specifications should facilitate interoperability. Furthermore, implementations and deployments of TCG specifications should not introduce any new interoperability obstacles that are not for the purpose of security.
  • Portability of data: Deployment should support established principles and practices of data ownership.
  • Controllability: Each owner should have effective choice and control over the use and operation of the TCG-enabled capabilities that belong to them; their participation must be opt-in. Subsequently, any user should be able to reliably disable the TCG functionality in a way that does not violate the owner’s policy.
  • Ease-of-use: The nontechnical user should find the TCG-enabled capabilities comprehensible and usable.

It’s basically a good document, although there are some valid criticisms. I like that the document clearly states that coercive use of the technology—forcing people to use digital rights management systems, for example, are inappropriate:

The use of coercion to effectively force the use of the TPM capabilities is not an appropriate use of the TCG technology.

I like that the document tries to protect user privacy:

All implementations of TCG-enabled components should ensure that the TCG technology is not inappropriately used for data aggregation of personal information/

I wish that interoperability were more strongly enforced. The language has too much wiggle room for companies to break interoperability under the guise of security:

Furthermore, implementations and deployments of TCG specifications should not introduce any new interoperability obstacles that are not for the purpose of security.

That sounds good, but what does “security” mean in that context? Security of the user against malicious code? Security of big media against people copying music and videos? Security of software vendors against competition? The big problem with TCG technology is that it can be used to further all three of these “security” goals, and this document is where “security” should be better defined.

Complaints aside, it’s a good document and we should all hope that companies follow it. Compliance is totally voluntary, but it’s the kind of document that governments and large corporations can point to and demand that vendors follow.

But there’s something fishy going on. Microsoft is doing its best to stall the document, and to ensure that it doesn’t apply to Vista (formerly known as Longhorn), Microsoft’s next-generation operating system.

The document was first written in the fall of 2003, and went through the standard review process in early 2004. Microsoft delayed the adoption and publication of the document, demanding more review. Eventually the document was published in June of this year (with a May date on the cover).

Meanwhile, the TCG built a purely software version of the specification: Trusted Network Connect (TNC). Basically, it’s a TCG system without a TPM.

The best practices document doesn’t apply to TNC, because Microsoft (as a member of the TCG board of directors) blocked it. The excuse is that the document hadn’t been written with software-only applications in mind, so it shouldn’t apply to software-only TCG systems.

This is absurd. The document outlines best practices for how the system is used. There’s nothing in it about how the system works internally. There’s nothing unique to hardware-based systems, nothing that would be different for software-only systems. You can go through the document yourself and replace all references to “TPM” or “hardware” with “software” (or, better yet, “hardware or software”) in five minutes. There are about a dozen changes, and none of them make any meaningful difference.

The only reason I can think of for all this Machiavellian maneuvering is that the TCG board of directors is making sure that the document doesn’t apply to Vista. If the document isn’t published until after Vista is released, then obviously it doesn’t apply.

Near as I can tell, no one is following this story. No one is asking why TCG best practices apply to hardware-based systems if they’re writing software-only specifications. No one is asking why the document doesn’t apply to all TCG systems, since it’s obviously written without any particular technology in mind. And no one is asking why the TCG is delaying the adoption of any software best practices.

I believe the reason is Microsoft and Vista, but clearly there’s some investigative reporting to be done.

(A version of this essay previously appeared on CNet’s News.com and ZDNet.)

EDITED TO ADD: This comment completely misses my point. Which is odd; I thought I was pretty clear.

EDITED TO ADD: There is a thread on Slashdot on the topic.

EDITED TO ADD: The Sydney Morning Herald republished this essay. Also “The Age.”

Posted on August 31, 2005 at 8:27 AM • View Comments

Xbox Security

Interesting article: “The Hidden Boot Code of the Xbox, or How to fit three bugs in 512 bytes of security code.”

Microsoft wanted to lock out both pirated games and unofficial games, so they built a chain of trust on the Xbox from the hardware to the execution of the game code. Only code authorized by Microsoft could run on the Xbox. The link between hardware and software in this chain of trust is the hidden “MCPX” boot ROM. The article discusses that ROM.

Lots of kindergarten security mistakes.

Posted on August 10, 2005 at 1:00 PM • View Comments

Orlando Airport's CLEAR Program

Orlando Airport is piloting a new pre-screening program called CLEAR. The idea is that you pay $80 a year and subject yourself to a background check, and then you can use a faster security line at airports.

I’ve already written about this idea, back when Steven Brill first started talking about it:

My primary security concerns surrounding this system stem from what it’s trying to do. In his writings and speaking, Brill is very careful to explain that these are not “trusted traveler cards.” He calls them “verified identity cards.” But the only purpose of his card is to divide people into two lines—a fast line and a slow line, a “search less” line and a “search more” line, or whatever….

The reality is that the existence of the card creates a third, and very dangerous, category: bad guys with the card. Timothy McVeigh would have been able to get one of these cards. The DC sniper and the Unabomber would have been able to get this card. Any terrorist mole who hasn’t done anything yet and is being saved for something big would be able to get this card. Some of the 9/11 terrorists would have been able to get this card. These are people who are deemed trustworthy by the system even though they are not.

And even worse, the system lets terrorists test the system beforehand. Imagine you’re in a terrorist cell. Twelve of you apply for the card, but only four of you get it. Those four not only have a card that lets them go through the easy line at security checkpoints; they also know that they’re not on any terrorist watch lists. Which four do you think will be going on the mission? By “pre-approving” trust, you’re building a system that is easier to exploit.

Nothing in this program is different from what I wrote about last year. According to their website:

Your Membership will be continuously reviewed by TSA’s ongoing Security Threat Assessment Process. If your security status changes, your Membership will be immediately deactivated and you will receive a notification email of your status change as well as a refund of the unused portion of your annual enrollment fee.

Think about it. For $80 a year, any potential terrorist can be automatically notified if the Department of Homeland Security is on to him. Such a deal.

Posted on August 8, 2005 at 8:03 AM • View Comments

How to Not Fix the ID Problem

Several of the 9/11 terrorists had Virginia driver’s licenses in fake names. These were not forgeries; these were valid Virginia IDs that were illegally sold by Department of Motor Vehicle workers.

So what did Virginia do to correct the problem? They required more paperwork in order to get an ID.

But the problem wasn’t that it was too easy to get an ID. The problem was that insiders were selling them illegally. Which is why the Virginia “solution” didn’t help, and the problem remains:

The manager of the Virginia Department of Motor Vehicles office at Springfield Mall was charged yesterday with selling driver’s licenses to illegal immigrants and others for up to $3,500 apiece.

The arrest of Francisco J. Martinez marked the second time in two years that a Northern Virginia DMV employee was accused of fraudulently selling licenses for cash. A similar scheme two years ago at the DMV office in Tysons Corner led to the guilty pleas of two employees.

And after we spend billions on the REAL ID act, and require even more paperwork to get a state ID, the problem will still remain.

Posted on July 19, 2005 at 1:15 PM • View Comments

Orlando Trusted Traveler Program

I’ve already written about what a bad idea trusted traveler programs are. The basic security intuition is that when you create two paths through security—an easy path and a hard path—you invite the bad guys to take the easy path. So the security of the sort process must make up for the security lost in the sorting. Trusted traveler fails this test; there are so many ways for the terrorists to get trusted traveler cards that the system makes it too easy for them to avoid the hard path through security.

The trusted traveler programs at various U.S. airports are all run by the TSA. A new program in Orlando Airport is run by the company Verified Identity Pass Inc.

I’ve already written about this company and what it’s doing.

And I’ve already written about the fallacy of confusing identification with security.

Posted on June 12, 2005 at 8:57 AM • View Comments

Burglars and "Feeling Secure"

From Confessions of a Master Jewel Thief by Bill Mason (Villard, 2003):

Nothing works more in a thief’s favor than people feeling secure. That’s why places that are heavily alarmed and guarded can sometimes be the easiest targets. The single most important factor in security—more than locks, alarms, sensors, or armed guards—is attitude. A building protected by nothing more than a cheap combination lock but inhabited by people who are alert and risk-aware is much safer than one with the world’s most sophisticated alarm system whose tenants assume they’re living in an impregnable fortress.

The author, a burglar, found that luxury condos were an excellent target. Although they had much more security technology than other buildings, they were vulnerable because no one believed a thief could get through the lobby.

Posted on December 17, 2004 at 9:21 AM • View Comments

Hacking Faxes

Prisoner is freed from jail based on a forged fax:

In West Memphis District Court yesterday, Tristian Wilson was set to appear on the docket for a bond hearing on the charges. When he did not appear, Judge William “Pal” Rainey inquired about his release and found that a jail staff member released Wilson by the authority of a fax sent to the jail late Saturday night.

According to Assistant Chief Mike Allen, a fax was sent to the jail which stated “Upon decision between Judge Rainey and the West Memphis Police Department CID Division Tristian Wilson is to be released immediately on this date of October 30, 2004 with a waiver of all fines, bonds and settlements per Judge Rainey and Detective McDugle.”

Jail Administrator Mickey Thornton said that these faxes are part of a normal routine for the jail when it comes to releasing prisoners, however, this fax was different.

Faxes are fascinating. They’re treated like original documents, but lack any of the authentication mechanisms that we’ve developed for original documents: letterheads, watermarks, signatures. Most of the time there’s no problem, but sometimes you can exploit people’s innate trust in faxes to good effect.

Posted on November 8, 2004 at 7:12 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.