Write-Once Read-Many Memory Cards
SanDisk has introduced Write-Once Read-Many Memory (WORM) cards for forensic applications.
Entries Tagged "hardware"
Page 15 of 18
Hacking a Coffee Machine
A Jura F90 Coffee Machine can be hacked remotely over the Internet.
Designing Processors to Support Hacking
This won best-paper award at the First USENIX Workshop on Large-Scale Exploits and Emergent Threats: “Designing and implementing malicious hardware,” by Samuel T. King, Joseph Tucek, Anthony Cozzie, Chris Grier, Weihang Jiang, and Yuanyuan Zhou.
Hidden malicious circuits provide an attacker with a stealthy attack vector. As they occupy a layer below the entire software stack, malicious circuits can bypass traditional defensive techniques. Yet current work on trojan circuits considers only simple attacks against the hardware itself, and straightforward defenses. More complex designs that attack the software are unexplored, as are the countermeasures an attacker may take to bypass proposed defenses.
We present the design and implementation of Illinois Malicious Processors (IMPs). There is a substantial design space in malicious circuitry; we show that an attacker, rather than designing one speci?c attack, can instead design hardware to support attacks. Such ?exible hardware allows powerful, general purpose attacks, while remaining surprisingly low in the amount of additional hardware. We show two such hardware designs, and implement them in a real system. Further, we show three powerful attacks using this hardware, including a login backdoor that gives an attacker complete and highlevel access to the machine. This login attack requires only 1341 additional gates: gates that can be used for other attacks as well. Malicious processors are more practical, more flexible, and harder to detect than an initial analysis would suggest.
Theoretical? Sure. But combine this with stories of counterfeit computer hardware from China, and you’ve got yourself a potentially serious problem.
Cold Boot Attacks Against Disk Encryption
Nice piece of research:
We show that disk encryption, the standard approach to protecting sensitive data on laptops, can be defeated by relatively simple methods. We demonstrate our methods by using them to defeat three popular disk encryption products: BitLocker, which comes with Windows Vista; FileVault, which comes with MacOS X; and dm-crypt, which is used with Linux.
[…]
The root of the problem lies in an unexpected property of today’s DRAM memories. DRAMs are the main memory chips used to store data while the system is running. Virtually everybody, including experts, will tell you that DRAM contents are lost when you turn off the power. But this isn’t so. Our research shows that data in DRAM actually fades out gradually over a period of seconds to minutes, enabling an attacker to read the full contents of memory by cutting power and then rebooting into a malicious operating system.
Interestingly, if you cool the DRAM chips, for example by spraying inverted cans of “canned air” dusting spray on them, the chips will retain their contents for much longer. At these temperatures (around -50 °C) you can remove the chips from the computer and let them sit on the table for ten minutes or more, without appreciable loss of data. Cool the chips in liquid nitrogen (-196 °C) and they hold their state for hours at least, without any power. Just put the chips back into a machine and you can read out their contents.
This is deadly for disk encryption products because they rely on keeping master decryption keys in DRAM. This was thought to be safe because the operating system would keep any malicious programs from accessing the keys in memory, and there was no way to get rid of the operating system without cutting power to the machine, which “everybody knew” would cause the keys to be erased.
Our results show that an attacker can cut power to the computer, then power it back up and boot a malicious operating system (from, say, a thumb drive) that copies the contents of memory. Having done that, the attacker can search through the captured memory contents, find any crypto keys that might be there, and use them to start decrypting hard disk contents. We show very effective methods for finding and extracting keys from memory, even if the contents of memory have faded somewhat (i.e., even if some bits of memory were flipped during the power-off interval). If the attacker is worried that memory will fade too quickly, he can chill the DRAM chips before cutting power.
There seems to be no easy fix for these problems. Fundamentally, disk encryption programs now have nowhere safe to store their keys. Today’s Trusted Computing hardware does not seem to help; for example, we can defeat BitLocker despite its use of a Trusted Platform Module.
The paper is here; more info is here. Articles here.
There is a general security problem illustrated here: it is very difficult to secure data when the attacker has physical control of the machine the data is stored on. I talk about the general problem here, and it’s a hard problem.
EDITED TO ADD (2/26): How-to, with pictures.
Hacking Thermostats
I have absolutely no doubt that there will be security flaws in remotely controllable thermostats, allowing hackers to seize control of them. Do this on a too-hot day, and you might even cause a large blackout.
Hard Drives Sold with Pre-Installed Trojans
I don’t know if this story is true:
Portable hard discs sold locally and produced by US disk-drive manufacturer Seagate Technology have been found to carry Trojan horse viruses that automatically upload to Beijing Web sites anything the computer user saves on the hard disc, the Investigation Bureau said.
Around 1,800 of the portable Maxtor hard discs, produced in Thailand, carried two Trojan horse viruses: autorun.inf and ghost.pif, the bureau under the Ministry of Justice said.
The tainted portable hard disc uploads any information saved on the computer automatically and without the owner’s knowledge to www.nice8.org and www.we168.org, the bureau said.
Certainly possible.
EDITED TO ADD (12/14): A first-hand account.
Eavesdropping on a Fiber Optic Cable
It’s easy to eavesdrop on a copper cable; fiber optic cable is much harder. Here’s how to eavesdrop on a fiber optic cable: total hardware cost less than $1,000.
Intel Security Music Video
…directed by Christopher Guest: hardware vs software security.
I don’t know what to say. I can’t believe the actors kept a straight face.
A Security Market for Lemons
More than a year ago, I wrote about the increasing risks of data loss because more and more data fits in smaller and smaller packages. Today I use a 4-GB USB memory stick for backup while I am traveling. I like the convenience, but if I lose the tiny thing I risk all my data.
Encryption is the obvious solution for this problem—I use PGPdisk—but Secustick sounds even better: It automatically erases itself after a set number of bad password attempts. The company makes a bunch of other impressive claims: The product was commissioned, and eventually approved, by the French intelligence service; it is used by many militaries and banks; its technology is revolutionary.
Unfortunately, the only impressive aspect of Secustick is its hubris, which was revealed when Tweakers.net completely broke its security. There’s no data self-destruct feature. The password protection can easily be bypassed. The data isn’t even encrypted. As a secure storage device, Secustick is pretty useless.
On the surface, this is just another snake-oil security story. But there’s a deeper question: Why are there so many bad security products out there? It’s not just that designing good security is hard—although it is—and it’s not just that anyone can design a security product that he himself cannot break. Why do mediocre security products beat the good ones in the marketplace?
In 1970, American economist George Akerlof wrote a paper called “The Market for ‘Lemons‘” (abstract and article for pay here), which established asymmetrical information theory. He eventually won a Nobel Prize for his work, which looks at markets where the seller knows a lot more about the product than the buyer.
Akerlof illustrated his ideas with a used car market. A used car market includes both good cars and lousy ones (lemons). The seller knows which is which, but the buyer can’t tell the difference—at least until he’s made his purchase. I’ll spare you the math, but what ends up happening is that the buyer bases his purchase price on the value of a used car of average quality.
This means that the best cars don’t get sold; their prices are too high. Which means that the owners of these best cars don’t put their cars on the market. And then this starts spiraling. The removal of the good cars from the market reduces the average price buyers are willing to pay, and then the very good cars no longer sell, and disappear from the market. And then the good cars, and so on until only the lemons are left.
In a market where the seller has more information about the product than the buyer, bad products can drive the good ones out of the market.
The computer security market has a lot of the same characteristics of Akerlof’s lemons market. Take the market for encrypted USB memory sticks. Several companies make encrypted USB drives—Kingston Technology sent me one in the mail a few days ago—but even I couldn’t tell you if Kingston’s offering is better than Secustick. Or if it’s better than any other encrypted USB drives. They use the same encryption algorithms. They make the same security claims. And if I can’t tell the difference, most consumers won’t be able to either.
Of course, it’s more expensive to make an actually secure USB drive. Good security design takes time, and necessarily means limiting functionality. Good security testing takes even more time, especially if the product is any good. This means the less-secure product will be cheaper, sooner to market and have more features. In this market, the more-secure USB drive is going to lose out.
I see this kind of thing happening over and over in computer security. In the late 1980s and early 1990s, there were more than a hundred competing firewall products. The few that “won” weren’t the most secure firewalls; they were the ones that were easy to set up, easy to use and didn’t annoy users too much. Because buyers couldn’t base their buying decision on the relative security merits, they based them on these other criteria. The intrusion detection system, or IDS, market evolved the same way, and before that the antivirus market. The few products that succeeded weren’t the most secure, because buyers couldn’t tell the difference.
How do you solve this? You need what economists call a “signal,” a way for buyers to tell the difference. Warranties are a common signal. Alternatively, an independent auto mechanic can tell good cars from lemons, and a buyer can hire his expertise. The Secustick story demonstrates this. If there is a consumer advocate group that has the expertise to evaluate different products, then the lemons can be exposed.
Secustick, for one, seems to have been withdrawn from sale.
But security testing is both expensive and slow, and it just isn’t possible for an independent lab to test everything. Unfortunately, the exposure of Secustick is an exception. It was a simple product, and easily exposed once someone bothered to look. A complex software product—a firewall, an IDS—is very hard to test well. And, of course, by the time you have tested it, the vendor has a new version on the market.
In reality, we have to rely on a variety of mediocre signals to differentiate the good security products from the bad. Standardization is one signal. The widely used AES encryption standard has reduced, although not eliminated, the number of lousy encryption algorithms on the market. Reputation is a more common signal; we choose security products based on the reputation of the company selling them, the reputation of some security wizard associated with them, magazine reviews, recommendations from colleagues or general buzz in the media.
All these signals have their problems. Even product reviews, which should be as comprehensive as the Tweakers’ Secustick review, rarely are. Many firewall comparison reviews focus on things the reviewers can easily measure, like packets per second, rather than how secure the products are. In IDS comparisons, you can find the same bogus “number of signatures” comparison. Buyers lap that stuff up; in the absence of deep understanding, they happily accept shallow data.
With so many mediocre security products on the market, and the difficulty of coming up with a strong quality signal, vendors don’t have strong incentives to invest in developing good products. And the vendors that do tend to die a quiet and lonely death.
This essay originally appeared in Wired.
EDITED TO ADD (4/22): Slashdot thread.
Stealing Data from Disk Drives in Photocopiers
This is a threat I hadn’t thought of before:
Now, experts are warning that photocopiers could be a culprit as well.
That’s because most digital copiers manufactured in the past five years have disk drives—the same kind of data-storage mechanism found in computers—to reproduce documents.
As a result, the seemingly innocuous machines that are commonly used to spit out copies of tax returns for millions of Americans can retain the data being scanned.
If the data on the copier’s disk aren’t protected with encryption or an overwrite mechanism, and if someone with malicious motives gets access to the machine, industry experts say sensitive information from original documents could get into the wrong hands.
Sidebar photo of Bruce Schneier by Joe MacInnis.