Schneier on Security: Tagged operating systems

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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

New Windows Vulnerability

There’s a new Windows 2000 vulnerability:

A serious flaw has been discovered in a core component of Windows 2000, with no possible work-around until it gets fixed, a security company said.

The vulnerability in Microsoft’s operating system could enable remote intruders to enter a PC via its Internet Protocol address, Marc Maiffret, chief hacking officer at eEye Digital Security, said on Wednesday. As no action on the part of the computer user is required, the flaw could easily be exploited to create a worm attack, he noted.

What may be particularly problematic with this unpatched security hole is that a work-around is unlikely, he said.

“You can’t turn this (vulnerable) component off,” Maiffret said. “It’s always on. You can’t disable it. You can’t uninstall.”

Don’t fail to notice the sensationalist explanation from eEye. This is what I call a “publicity attack” (note that the particular example in that essay is wrong): it’s an attempt by eEye Digital Security to get publicity for their company. Yes, I’m sure it’s a bad vulnerability. Yes, I’m sure Microsoft should have done more to secure their systems. But eEye isn’t blameless in this; they’re searching for vulnerabilities that make good press releases.

Posted on August 5, 2005 at 2:25 PM • View Comments

Microsoft Permits Pirated Software to Receive Security Patches

Microsoft wants to make pirated software less useful by preventing it from receiving patches and updates. At the same time, it is in everyone’s best interest for all software to be more secure: legitimate and pirated. This issue has been percolating for a while, and I’ve written about it twice before. After much back and forth, Microsoft is going to do the right thing:

From now on, customers looking to get the latest add-ons to Windows will have to verify that their copy of the operating system is legit….

The only exception is for security-related patches. Regardless of whether a system passes the test, security updates will be available to all Windows users via either manual download or automatic update.

Microsoft deserves praise for this.

On the other hand, the system was cracked within 24 hours.

Posted on July 29, 2005 at 11:26 AM • View Comments

Pirated Windows to Remain Unpatched

From the Associated Press:

Microsoft Corp. plans to severely curtail the ways in which people running pirated copies of its dominant Windows operating system can receive software updates, including security fixes.

The new authentication system, announced Tuesday and due to arrive by midyear, will still allow people with pirated copies of Windows to obtain security fixes, but their options will be limited. The move allows Microsoft to use one of its sharpest weapons—access to security patches that can prevent viruses, worms and other crippling attacks—to thwart a costly and meddlesome piracy problem.

I’ve written about this before. Unpatched Windows systems on the Internet are a security risk to everyone. I understand Microsoft wanting to fight piracy, but reducing the security of its paying customers is not a good way to go about it.

Posted on February 17, 2005 at 8:00 AM • View Comments

GhostBuster

This is a really interesting technical report from Microsoft. It describes a clever prototype—called GhostBuster—they developed for detecting arbitrary persistent and stealthy software, such as rootkits, Trojans, and software keyloggers. It’s a really elegant idea, based on a simple observation: the rootkit must exist on disk to be persistent, but must lie to programs running within the infected OS in order to hide.

Here’s how it works: The user has the GhostBuster program on a CD. He sticks the CD in the drive, and from within the (possibly corrupted) OS, the checker program runs: stopping all other user programs, flushing the caches, and then doing a complete checksum of all files on the disk and a scan of any registry keys that could autostart the system, writing out the results to a file on the hard drive.

Then the user is instructed to press the reset button, the CD boots its own OS, and the scan is repeated. Any differences indicate a rootkit or other stealth software, without the need for knowing what particular rootkits are or the proper checksums for the programs installed on disk.

Simple. Clever. Elegant.

In order to fool GhostBuster, the rootkit must 1) detect that such a checking program is running and either not lie to it or change the output as it’s written to disk (in the limit this becomes the halting problem for the rootkit designer), 2) integrate into the BIOS rather than the OS (tricky, platform specific, and not always possible), or 3) give up on either being persistent or stealthy. Thus this doesn’t eliminate rootkits entirely, but is a pretty mortal blow to persistent rootkits.

Of course, the concept could be adopted for any other operating system as well.

This is a great idea, but there’s a huge problem. GhostBuster is only a research prototype, so you can’t get a copy. And, even worse, Microsoft has no plans to turn it into a commercial tool.

This is too good an idea to abandon. Microsoft, if you’re listening, you should release this tool to the world. Make it public domain. Make it open source, even. It’s a great idea, and you deserve credit for coming up with it.

Any other security companies listening? Make and sell one of these. Anyone out there looking for an open source project? Here’s a really good one.

Note: I have no idea if Microsoft patented this idea. If they did and they don’t release it, shame on them. If they didn’t, good for them.

Posted on February 15, 2005 at 8:00 AM • View Comments

Automobile Virus

SC Magazine is reporting on a virus that infects Lexus cars:

Lexus cars may be vulnerable to viruses that infect them via mobile phones. Landcruiser 100 models LX470 and LS430 have been discovered with infected operating systems that transfer within a range of 15 feet.

It seems that no one has done this yet, and the story is based on speculation that a cell phone can transfer a virus to the Lexus using Bluetooth. But it’s only a matter of time before something like this actually works.

Posted on February 2, 2005 at 8:00 AM • View Comments

Linux Security

I’m a big fan of the Honeynet Project (and a member of their board of directors). They don’t have a security product; they do security research. Basically, they wire computers up with sensors, put them on the Internet, and watch hackers attack them.

They just released a report about the security of Linux:

Recent data from our honeynet sensor grid reveals that the average life expectancy to compromise for an unpatched Linux system has increased from 72 hours to 3 months. This means that a unpatched Linux system with commonly used configurations (such as server builds of RedHat 9.0 or Suse 6.2) have an online mean life expectancy of 3 months before being successfully compromised.

This is much greater than that of Windows systems, which have average life expectancies on the order of a few minutes.

It’s also important to remember that this paper focuses on vulnerable systems. The Honeynet researchers deployed almost 20 vulnerable systems to monitor hacker tactics, and found that no one was hacking the systems. That’s the real story: the hackers aren’t bothering with Linux. Two years ago, a vulnerable Linux system would be hacked in less than three days; now it takes three months.

Why? My guess is a combination of two reasons. One, Linux is that much more secure than Windows. Two, the bad guys are focusing on Windows—more bang for the buck.

Safe Personal Computing

I am regularly asked what average Internet users can do to ensure their security. My first answer is usually, “Nothing—you’re screwed.”

But that’s not true, and the reality is more complicated. You’re screwed if you do nothing to protect yourself, but there are many things you can do to increase your security on the Internet.

Two years ago, I published a list of PC security recommendations. The idea was to give home users concrete actions they could take to improve security. This is an update of that list: a dozen things you can do to improve your security.

General: Turn off the computer when you’re not using it, especially if you have an “always on” Internet connection.

Laptop security: Keep your laptop with you at all times when not at home; treat it as you would a wallet or purse. Regularly purge unneeded data files from your laptop. The same goes for PDAs. People tend to store more personal data—including passwords and PINs—on PDAs than they do on laptops.

Backups: Back up regularly. Back up to disk, tape or CD-ROM. There’s a lot you can’t defend against; a recent backup will at least let you recover from an attack. Store at least one set of backups off-site (a safe-deposit box is a good place) and at least one set on-site. Remember to destroy old backups. The best way to destroy CD-Rs is to microwave them on high for five seconds. You can also break them in half or run them through better shredders.

Operating systems: If possible, don’t use Microsoft Windows. Buy a Macintosh or use Linux. If you must use Windows, set up Automatic Update so that you automatically receive security patches. And delete the files “command.com” and “cmd.exe.”

Applications: Limit the number of applications on your machine. If you don’t need it, don’t install it. If you no longer need it, uninstall it. Look into one of the free office suites as an alternative to Microsoft Office. Regularly check for updates to the applications you use and install them. Keeping your applications patched is important, but don’t lose sleep over it.

Browsing: Don’t use Microsoft Internet Explorer, period. Limit use of cookies and applets to those few sites that provide services you need. Set your browser to regularly delete cookies. Don’t assume a Web site is what it claims to be, unless you’ve typed in the URL yourself. Make sure the address bar shows the exact address, not a near-miss.

Web sites: Secure Sockets Layer (SSL) encryption does not provide any assurance that the vendor is trustworthy or that its database of customer information is secure.

Think before you do business with a Web site. Limit the financial and personal data you send to Web sites—don’t give out information unless you see a value to you. If you don’t want to give out personal information, lie. Opt out of marketing notices. If the Web site gives you the option of not storing your information for later use, take it. Use a credit card for online purchases, not a debit card.

Passwords: You can’t memorize good enough passwords any more, so don’t bother. For high-security Web sites such as banks, create long random passwords and write them down. Guard them as you would your cash: i.e., store them in your wallet, etc.

Never reuse a password for something you care about. (It’s fine to have a single password for low-security sites, such as for newspaper archive access.) Assume that all PINs can be easily broken and plan accordingly.

Never type a password you care about, such as for a bank account, into a non-SSL encrypted page. If your bank makes it possible to do that, complain to them. When they tell you that it is OK, don’t believe them; they’re wrong.

E-mail : Turn off HTML e-mail. Don’t automatically assume that any e-mail is from the “From” address.

Delete spam without reading it. Don’t open messages with file attachments, unless you know what they contain; immediately delete them. Don’t open cartoons, videos and similar “good for a laugh” files forwarded by your well-meaning friends; again, immediately delete them.

Never click links in e-mail unless you’re sure about the e-mail; copy and paste the link into your browser instead. Don’t use Outlook or Outlook Express. If you must use Microsoft Office, enable macro virus protection; in Office 2000, turn the security level to “high” and don’t trust any received files unless you have to. If you’re using Windows, turn off the “hide file extensions for known file types” option; it lets Trojan horses masquerade as other types of files. Uninstall the Windows Scripting Host if you can get along without it. If you can’t, at least change your file associations, so that script files aren’t automatically sent to the Scripting Host if you double-click them.

Antivirus and anti-spyware software : Use it—either a combined program or two separate programs. Download and install the updates, at least weekly and whenever you read about a new virus in the news. Some antivirus products automatically check for updates. Enable that feature and set it to “daily.”

Firewall : Spend $50 for a Network Address Translator firewall device; it’s likely to be good enough in default mode. On your laptop, use personal firewall software. If you can, hide your IP address. There’s no reason to allow any incoming connections from anybody.

Encryption: Install an e-mail and file encryptor (like PGP). Encrypting all your e-mail or your entire hard drive is unrealistic, but some mail is too sensitive to send in the clear. Similarly, some files on your hard drive are too sensitive to leave unencrypted.

None of the measures I’ve described are foolproof. If the secret police wants to target your data or your communications, no countermeasure on this list will stop them. But these precautions are all good network-hygiene measures, and they’ll make you a more difficult target than the computer next door. And even if you only follow a few basic measures, you’re unlikely to have any problems.

I’m stuck using Microsoft Windows and Office, but I use Opera for Web browsing and Eudora for e-mail. I use Windows Update to automatically get patches and install other patches when I hear about them. My antivirus software updates itself regularly. I keep my computer relatively clean and delete applications that I don’t need. I’m diligent about backing up my data and about storing data files that are no longer needed offline.

I’m suspicious to the point of near-paranoia about e-mail attachments and Web sites. I delete cookies and spyware. I watch URLs to make sure I know where I am, and I don’t trust unsolicited e-mails. I don’t care about low-security passwords, but try to have good passwords for accounts that involve money. I still don’t do Internet banking. I have my firewall set to deny all incoming connections. And I turn my computer off when I’m not using it.

That’s basically it. Really, it’s not that hard. The hardest part is developing an intuition about e-mail and Web sites. But that just takes experience.

This essay previously appeared on CNet

Posted on December 13, 2004 at 9:59 AM • View Comments

Schneier: Microsoft still has work to do

Bruce Schneier is founder and chief technology officer of Mountain View, Calif.-based MSSP Counterpane Internet Security Inc. and author of Applied Cryptography, Secrets and Lies, and Beyond Fear. He also publishes Crypto-Gram, a free monthly newsletter, and writes op-ed pieces for various publications. Schneier spoke to SearchSecurity.com about the latest threats, Microsoft’s ongoing security struggles and other topics in a two-part interview that took place by e-mail and phone last month. In this installment, he talks about the “hype” of SP2 and explains why it’s “foolish” to use Internet Explorer.

What’s the biggest threat to information security at the moment?

Schneier: Crime. Criminals have discovered IT in a big way. We’re seeing a huge increase in identity theft and associated financial theft. We’re seeing a rise in credit card fraud. We’re seeing a rise in blackmail. Years ago, the people breaking into computers were mostly kids participating in the information-age equivalent of spray painting. Today there’s a profit motive, as those same hacked computers become launching pads for spam, phishing attacks and Trojans that steal passwords. Right now we’re seeing a crime wave against Internet consumers that has the potential to radically change the way people use their computers. When enough average users complain about having money stolen, the government is going to step in and do something. The results are unlikely to be pretty.

Which threats are overly hyped?

Schneier: Cyberterrorism. It’s not much of a threat. These attacks are very difficult to execute. The software systems controlling our nation’s infrastructure are filled with vulnerabilities, but they’re generally not the kinds of vulnerabilities that cause catastrophic disruptions. The systems are designed to limit the damage that occurs from errors and accidents. They have manual overrides. These systems have been proven to work; they’ve experienced disruptions caused by accident and natural disaster. We’ve been through blackouts, telephone switch failures and disruptions of air traffic control computers. The results might be annoying, and engineers might spend days or weeks scrambling, but it doesn’t spread terror. The effect on the general population has been minimal.

Microsoft has made much of the added security muscle in SP2. Has it measured up to the hype?

Schneier: SP2 is much more hype than substance. It’s got some cool things, but I was unimpressed overall. It’s a pity, though. They had an opportunity to do more, and I think they could have done more. But even so, this stuff is hard. I think the fact that SP2 was largely superficial speaks to how the poor security choices Microsoft made years ago are deeply embedded inside the operating system.

Is Microsoft taking security more seriously?

Schneier: Microsoft is certainly taking it more seriously than three years ago, when they ignored it completely. But they’re still not taking security seriously enough for me. They’ve made some superficial changes in the way they approach security, but they still treat it more like a PR problem than a technical problem. To me, the problem is economic. Microsoft—or any other software company—is not a charity, and we should not expect them to do something that hurts their bottom line. As long as we all are willing to buy insecure software, software companies don’t have much incentive to make their products secure. For years I have been advocating software liability as a way of changing that balance. If software companies could get sued for defective products, just as automobile manufacturers are, then they would spend much more money making their products secure.

After the Download.ject attack in June, voices advocating alternatives to Internet Explorer grew louder. Which browser do you use?

Schneier: I think it’s foolish to use Internet Explorer. It’s filled with security holes, and it’s too hard to configure it to have decent security. Basically, it seems to be written in the best interests of Microsoft and not in the best interests of the customer. I have used the Opera browser for years, and I am very happy with it. It’s much better designed, and I never have to worry about Explorer-based attacks.

By Bill Brenner, News Writer
4 Oct 2004 | SearchSecurity.com

Posted on October 8, 2004 at 4:45 PM • View Comments

News

Last month I wrote: “Long and interesting review of Windows XP SP2, including a list of missed opportunities for increased security. Worth reading: The Register.” Be sure you read this follow-up as well:
The Register

The author of the Sasser worm has been arrested:
Computerworld
The Register
And been offered a job:
Australian IT

Interesting essay on the psychology of terrorist alerts:
Philip Zimbardo

Encrypted e-mail client for the Treo:
Treo Central

The Honeynet Project is publishing a bi-annual CD-ROM and newsletter. If you’re involved in honeynets, it’s definitely worth getting. And even if you’re not, it’s worth supporting this endeavor.
Honeynet

CIO Magazine has published a survey of corporate information security. I have some issues with the survey, but it’s worth reading.
IT Security

At the Illinois State Capitol, someone shot an unarmed security guard and fled. The security upgrade after the incident is—get ready—to change the building admittance policy from a “check IDs” procedure to a “sign in” procedure. First off, identity checking does not increase security. And secondly, why do they think that an attacker would be willing to forge/steal an identification card, but would be unwilling to sign their name on a clipboard?
The Guardian

Neat research: a quantum-encrypted TCP/IP network:
MetroWest Daily News
Slashdot
And NEC has its own quantum cryptography research results:
InfoWorld

Security story about the U.S. embassy in New Zealand. It’s a good lesson about the pitfalls of not thinking beyond the immediate problem.
The Dominion

The future of worms:
Computerworld

Teacher arrested after a bookmark is called a concealed weapon:
St. Petersburg Times
Remember all those other things you can bring on an aircraft that can knock people unconscious: handbags, laptop computers, hardcover books. And that dental floss can be used as a garrote. And, and, oh…you get the idea.

Seems you can open Kryptonite bicycle locks with the cap from a plastic pen. The attack works on what locksmiths call the “impressioning” principle. Tubular locks are especially vulnerable to this because all the pins are exposed, and tools that require little skill to use can be relatively unsophisticated. There have been commercial locksmithing products to do this to circular locks for a long time. Once you get the feel for how to do it, it’s pretty easy. I find Kryptonite’s proposed solution—swapping for a smaller diameter lock so a particular brand of pen won’t work—to be especially amusing.
Indystar.com
Wired
Bikeforums

I often talk about how most firewalls are ineffective because they’re not configured properly. Here’s some research on firewall configuration:
IEEE Computer

Reading RFID tags from three feet away:
Computerworld

AOL is offering two-factor authentication services. It’s not free: $10 plus $2 per month. It’s an RSA Security token, with a number that changes every 60 seconds.
PC World

Counter-terrorism has its own snake oil:
Quantum Sleeper

Posted on October 1, 2004 at 9:40 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.