Entries Tagged "computer security"

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Microsoft's BitLocker

BitLocker Drive Encryption is a new security feature in Windows Vista, designed to work with the Trusted Platform Module (TPM). Basically, it encrypts the C drive with a computer-generated key. In its basic mode, an attacker can still access the data on the drive by guessing the user’s password, but would not be able to get at the drive by booting the disk up using another operating system, or removing the drive and attaching it to another computer.

There are several modes for BitLocker. In the simplest mode, the TPM stores the key and the whole thing happens completely invisibly. The user does nothing differently, and notices nothing different.

The BitLocker key can also be stored on a USB drive. Here, the user has to insert the USB drive into the computer during boot. Then there’s a mode that uses a key stored in the TPM and a key stored on a USB drive. And finally, there’s a mode that uses a key stored in the TPM and a four-digit PIN that the user types into the computer. This happens early in the boot process, when there’s still ASCII text on the screen.

Note that if you configure BitLocker with a USB key or a PIN, password guessing doesn’t work. BitLocker doesn’t even let you get to a password screen to try.

For most people, basic mode is the best. People will keep their USB key in their computer bag with their laptop, so it won’t add much security. But if you can force users to attach it to their keychains—remember that you only need the key to boot the computer, not to operate the computer—and convince them to go through the trouble of sticking it in their computer every time they boot, then you’ll get a higher level of security.

There is a recovery key: optional but strongly encouraged. It is automatically generated by BitLocker, and it can be sent to some administrator or printed out and stored in some secure location. There are ways for an administrator to set group policy settings mandating this key.

There aren’t any back doors for the police, though.

You can get BitLocker to work in systems without a TPM, but it’s kludgy. You can only configure it for a USB key. And it only will work on some hardware: because BItLocker starts running before any device drivers are loaded, the BIOS must recognize USB drives in order for BitLocker to work.

Encryption particulars: The default data encryption algorithm is AES-128-CBC with an additional diffuser. The diffuser is designed to protect against ciphertext-manipulation attacks, and is independently keyed from AES-CBC so that it cannot damage the security you get from AES-CBC. Administrators can select the disk encryption algorithm through group policy. Choices are 128-bit AES-CBC plus the diffuser, 256-bit AES-CBC plus the diffuser, 128-bit AES-CBC, and 256-bit AES-CBC. (My advice: stick with the default.) The key management system uses 256-bit keys wherever possible. The only place where a 128-bit key limit is hard-coded is the recovery key, which is 48 digits (including checksums). It’s shorter because it has to be typed in manually; typing in 96 digits will piss off a lot of people—even if it is only for data recovery.

So, does this destroy dual-boot systems? Not really. If you have Vista running, then set up a dual boot system, Bitlocker will consider this sort of change to be an attack and refuse to run. But then you can use the recovery key to boot into Windows, then tell BitLocker to take the current configuration—with the dual boot code—as correct. After that, your dual boot system will work just fine, or so I’ve been told. You still won’t be able to share any files on your C drive between operating systems, but you will be able to share files on any other drive.

The problem is that it’s impossible to distinguish between a legitimate dual boot system and an attacker trying to use another OS—whether Linux or another instance of Vista—to get at the volume.

BitLocker is not a panacea. But it does mitigate a specific but significant risk: the risk of attackers getting at data on drives directly. It allows people to throw away or sell old drives without worry. It allows people to stop worrying about their drives getting lost or stolen. It stops a particular attack against data.

Right now BitLocker is only in the Ultimate and Enterprise editions of Vista. It’s a feature that is turned off by default. It is also Microsoft’s first TPM application. Presumably it will be enhanced in the future: allowing the encryption of other drives would be a good next step, for example.

EDITED TO ADD (5/3): BitLocker is not a DRM system. However, it is straightforward to turn it into a DRM system. Simply give programs the ability to require that files be stored only on BitLocker-enabled drives, and then only be transferrable to other BitLocker-enabled drives. How easy this would be to implement, and how hard it would be to subvert, depends on the details of the system.

Posted on May 2, 2006 at 6:54 AM • View Comments

VOIP Encryption

There are basically four ways to eavesdrop on a telephone call.

One, you can listen in on another phone extension. This is the method preferred by siblings everywhere. If you have the right access, it’s the easiest. While it doesn’t work for cell phones, cordless phones are vulnerable to a variant of this attack: A radio receiver set to the right frequency can act as another extension.

Two, you can attach some eavesdropping equipment to the wire with a pair of alligator clips. It takes some expertise, but you can do it anywhere along the phone line’s path—even outside the home. This used to be the way the police eavesdropped on your phone line. These days it’s probably most often used by criminals. This method doesn’t work for cell phones, either.

Three, you can eavesdrop at the telephone switch. Modern phone equipment includes the ability for someone to listen in this way. Currently, this is the preferred police method. It works for both land lines and cell phones. You need the right access, but if you can get it, this is probably the most comfortable way to eavesdrop on a particular person.

Four, you can tap the main trunk lines, eavesdrop on the microwave or satellite phone links, etc. It’s hard to eavesdrop on one particular person this way, but it’s easy to listen in on a large chunk of telephone calls. This is the sort of big-budget surveillance that organizations like the National Security Agency do best. They’ve even been known to use submarines to tap undersea phone cables.

That’s basically the entire threat model for traditional phone calls. And when most people think about IP telephony—voice over internet protocol, or VOIP—that’s the threat model they probably have in their heads.

Unfortunately, phone calls from your computer are fundamentally different from phone calls from your telephone. Internet telephony’s threat model is much closer to the threat model for IP-networked computers than the threat model for telephony.

And we already know the threat model for IP. Data packets can be eavesdropped on anywhere along the transmission path. Data packets can be intercepted in the corporate network, by the internet service provider and along the backbone. They can be eavesdropped on by the people or organizations that own those computers, and they can be eavesdropped on by anyone who has successfully hacked into those computers. They can be vacuumed up by nosy hackers, criminals, competitors and governments.

It’s comparable to threat No. 3 above, but with the scope vastly expanded.

My greatest worry is the criminal attacks. We already have seen how clever criminals have become over the past several years at stealing account information and personal data. I can imagine them eavesdropping on attorneys, looking for information with which to blackmail people. I can imagine them eavesdropping on bankers, looking for inside information with which to make stock purchases. I can imagine them stealing account information, hijacking telephone calls, committing identity theft. On the business side, I can see them engaging in industrial espionage and stealing trade secrets. In short, I can imagine them doing all the things they could never have done with the traditional telephone network.

This is why encryption for VOIP is so important. VOIP calls are vulnerable to a variety of threats that traditional telephone calls are not. Encryption is one of the essential security technologies for computer data, and it will go a long way toward securing VOIP.

The last time this sort of thing came up, the U.S. government tried to sell us something called “key escrow.” Basically, the government likes the idea of everyone using encryption, as long as it has a copy of the key. This is an amazingly insecure idea for a number of reasons, mostly boiling down to the fact that when you provide a means of access into a security system, you greatly weaken its security.

A recent case in Greece demonstrated that perfectly: Criminals used a cell-phone eavesdropping mechanism already in place, designed for the police to listen in on phone calls. Had the call system been designed to be secure in the first place, there never would have been a backdoor for the criminals to exploit.

Fortunately, there are many VOIP-encryption products available. Skype has built-in encryption. Phil Zimmermann is releasing Zfone, an easy-to-use open-source product. There’s even a VOIP Security Alliance.

Encryption for IP telephony is important, but it’s not a panacea. Basically, it takes care of threats No. 2 through No. 4, but not threat No. 1. Unfortunately, that’s the biggest threat: eavesdropping at the end points. No amount of IP telephony encryption can prevent a Trojan or worm on your computer—or just a hacker who managed to get access to your machine—from eavesdropping on your phone calls, just as no amount of SSL or e-mail encryption can prevent a Trojan on your computer from eavesdropping—or even modifying—your data.

So, as always, it boils down to this: We need secure computers and secure operating systems even more than we need secure transmission.

This essay originally appeared on Wired.com.

Posted on April 6, 2006 at 5:09 AM • View Comments

Computer-Controlled Fasteners

It’s a really clever idea: bolts and latches that fasten and unfasten in response to remote computer commands.

What Rudduck developed are fasteners analogous to locks in doors, only in this case messages are sent electronically to engage the parts to lock or unlock. A quick electrical charge triggered remotely by a device or computer may move the part to lock, while another jolt disengages the unit.

Instead of nuts and bolts to hold two things together, these fasteners use hooks, latches and so-called smart materials that can change shape on command.The first commercial applications are intended for aircraft, allowing crews to quickly reshape interiors to maximize payload space. For long flights, the plane may need more high-cost business-class seats, while shorter hauls prefer a more abundant supply of coach seats.

Pretty clever, actually. The whole article is interesting.

But this part scares me:

A potential security breach threat apparently doesn’t exist.

“I wondered what’s to prevent some nut using a garage door opener from pushing the right buttons to make your airplane fall apart,” said Harrison. “But everything is locked down with codes, and the radio signals are scrambled, so this is fully secured against hackers.”

Clearly this Harrison guy knows nothing about computer security.

EDITED TO ADD: Slashdot has a thread on the topic.

Posted on April 3, 2006 at 12:57 PM • View Comments

iJacking

The San Francisco Bay Guardian is reporting on a new crime: people who grab laptops out of their owners’ hands and then run away. It’s called “iJacking,” and there seems to be a wave of this type of crime at Internet cafes in San Francisco:

In 2004 the SFPD Robbery Division recorded 17 strong-arm laptop robberies citywide. This increased to 30 cases in 2005, a total that doesn’t even include thefts that fall under the category of “burglary,” when a victim isn’t present. (SFPD could not provide statistics on the number of laptop burglaries.)

In the past three months alone, Park Station, the police precinct that includes the Western Addition, has reported 11 strong-arm laptop robberies, a statistic that suggests this one district may exceed last year’s citywide total by the end of 2006.

Some stories:

Maloney was absorbed in his work when suddenly a hooded person yanked the laptop from Maloney’s hands and ran out the door. Maloney tried to grab his computer, but he stumbled across a few chairs and landed on the floor as the perpetrator dashed to a vehicle waiting a quarter block away.

[…]

Two weeks before Maloney’s robbery, on a Sunday afternoon, a man had been followed out of the Starbucks on the corner of Fulton Street and Masonic Avenue and was assaulted by two suspects in broad daylight. According to the police report, the suspects dragged the victim 15 feet along the pavement, kicking him in the face before stealing his computer.

In early February a women had her laptop snatched while sitting in Ali’s Café. She pursued the perpetrator out the door, only to be blindsided by a second accomplice. Ali described the assault as “a football tackle” so severe it left the victim’s eyeglasses in the branches of a nearby tree. In the most recent laptop robbery, on March 16 in a café on the 900 block of Valencia Street, police say the victim was actually stabbed.

It’s obvious why these thefts are occurring. Laptops are valuable, easy to steal, and easy to fence. If we want to “solve” this problem, we need to modify at least one of those characteristics. Some Internet cafes are providing locking cables for their patrons, in an attempt to make them harder to steal. But that will only mean that the muggers will follow their victims out of the cafes. Laptops will become less valuable over time, but that really isn’t a good solution. The only thing left is to make them harder to fence.

This isn’t an easy problem. There are a bunch of companies that make solutions that help people recover stolen laptops. There are programs that “phone home” if a laptop is stolen. There are programs that hide a serial number on the hard drive somewhere. There are non-removable tags users can affix to their computers with ID information. But until this kind of thing becomes common, the crimes will continue.

Reminds me of the problem of bicycle thefts.

Posted on March 31, 2006 at 1:06 PM • View Comments

RFID Chips and Viruses

Of course RFID chips can carry viruses. They’re just little computers.

More info here. The coverage is more than a tad sensationalist, though.

EDITED TO ADD (3/16): I thought the attack vector was interesting: a Trojan RFID attacks the central database, rather than attacking other RFID chips directly. Metaphorically, it’s a lot closer to biological viruses, because it actually requires the more powerful host being subverted, and there’s no way an infected tag could propagate directly to another tag.

Posted on March 16, 2006 at 6:55 AM • View Comments

AT&T's 1.9-Trillion-Call Database

This whole article is worth reading, but I found this tidbit particularly interesting:

He was alluding to databases maintained at an AT&T data center in Kansas, which now contain electronic records of 1.92 trillion telephone calls, going back decades. The Electronic Frontier Foundation, a digital-rights advocacy group, has asserted in a lawsuit that the AT&T Daytona system, a giant storehouse of calling records and Internet message routing information, was the foundation of the N.S.A.’s effort to mine telephone records without a warrant.

An AT&T spokeswoman said the company would not comment on the claim, or generally on matters of national security or customer privacy.

But the mining of the databases in other law enforcement investigations is well established, with documented results. One application of the database technology, called Security Call Analysis and Monitoring Platform, or Scamp, offers access to about nine weeks of calling information. It currently handles about 70,000 queries a month from fraud and law enforcement investigators, according to AT&T documents.

A former AT&T official who had detailed knowledge of the call-record database said the Daytona system takes great care to make certain that anyone using the database – whether AT&T employee or law enforcement official with a subpoena – sees only information he or she is authorized to see, and that an audit trail keeps track of all users. Such information is frequently used to build models of suspects’ social networks.

The official, speaking on condition of anonymity because he was discussing sensitive corporate matters, said every telephone call generated a record: number called, time of call, duration of call, billing category and other details. While the database does not contain such billing data as names, addresses and credit card numbers, those records are in a linked database that can be tapped by authorized users.

New calls are entered into the database immediately after they end, the official said, adding, “I would characterize it as near real time.”

According to a current AT&T employee, whose identity is being withheld to avoid jeopardizing his job, the mining of the AT&T databases had a notable success in helping investigators find the perpetrators of what was known as the Moldovan porn scam.

In 1997 a shadowy group in Moldova, a former Soviet republic, was tricking Internet users by enticing them to a pornography Web site that would download a piece of software that disconnected the computer user from his local telephone line and redialed a costly 900 number in Moldova.

While another long-distance carrier simply cut off the entire nation of Moldova from its network, AT&T and the Moldovan authorities were able to mine the database to track the culprits.

Posted on March 3, 2006 at 11:45 AM • View Comments

Quantum Computing Just Got More Bizarre

You don’t even have to turn it on:

With the right set-up, the theory suggested, the computer would sometimes get an answer out of the computer even though the program did not run. And now researchers from the University of Illinois at Urbana-Champaign have improved on the original design and built a non-running quantum computer that really works.

So now, even turning the machine off won’t necessarily prevent hackers from stealing passwords.

And as long as we’re on the topic of quantum computing, here’s a piece of quantum snake oil:

A University of Toronto professor says he can now use a photon of light to smash through the most sophisticated computer theft schemes that hackers can devise.

EDITED TO ADD (3/1): More information about the University of Illinois result is here.

Posted on February 28, 2006 at 1:14 PM • View Comments

More on Port Security

From Defective Yeti:

Sark Defends Port Deal

Sark today sought to quell the growing controversy over his decision to grant the MCP control of several major ports throughout the region.

“I believe that this arrangement with the Master Control Program should go forward,” Sark told reporters aboard Solar Sailer One. He emphasized that security would continued to be handled by Tank and Recognizer programs, with the MCP only be in charge of port operations.

But Dumont, guardian of the I/O towers, voiced skepticism. “I could understand ceding authority over ports 21 and 80,” said Dumont. “But port 443? That’s supposed to be secure!”

The public’s reaction to the plan has also been overwhelmingly negative. “No no no,” said a bit upon hearing the news. “No no no no.” Others were more blunt. “Sark should be de-rezzed for even proposing this,” said Ram, a financial program.

Sark, who has repeatedly denied having ties to the MCP, has insisted that the hand-over go through, and says that he will vigorously resist any effort to block it. But programs such as Yori are equally adamant that the deal be scuttled. “My User,” she said, “have we already forgotten the lessons of 1000222846?”

Posted on February 27, 2006 at 6:12 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.