Schneier on Security: Tagged backups

Entries Tagged "backups"

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On Security Tokens

Mark Risher of Google extols the virtues of security keys:

I’ll say it again for the people in the back: with Security Keys, instead of the *user* needing to verify the site, the *site* has to prove itself to the key. Good security these days is about human factors; we have to take the onus off of the user as much as we can.

Furthermore, this “proof” from the site to the key is only permitted over close physical proximity (like USB, NFC, or Bluetooth). Unless the phisher is in the same room as the victim, they can’t gain access to the second factor.

This is why I keep using words like “transformative,” “revolutionary,” and “lit” (not so much anymore): SKs basically shrink your threat model from “anyone anywhere in the world who knows your password” to “people in the room with you right now.” Huge!

Cory Doctorow makes a critical point, that the system is only as good as its backup system:

I agree, but there’s an important caveat. Security keys usually have fallback mechanisms—some way to attach a new key to your account for when you lose or destroy your old key. These mechanisms may also rely on security keys, but chances are that they don’t (and somewhere down the line, there’s probably a fallback mechanism that uses SMS, or Google Authenticator, or an email confirmation loop, or a password, or an administrator who can be sweet talked by a social engineer).

So while the insight that traditional 2FA is really “something you know and something else you know, albeit only very recently,” security keys are “Something you know and something you have, which someone else can have, if they know something you know.”

And just because there are vulnerabilities in cell phone-based two-factor authentication systems doesn’t mean that they are useless. They’re still much better than traditional password-only authentication systems.

Posted on May 1, 2019 at 6:14 AM • View Comments

The Future of Ransomware

Ransomware isn’t new, but it’s increasingly popular and profitable.

The concept is simple: Your computer gets infected with a virus that encrypts your files until you pay a ransom. It’s extortion taken to its networked extreme. The criminals provide step-by-step instructions on how to pay, sometimes even offering a help line for victims unsure how to buy bitcoin. The price is designed to be cheap enough for people to pay instead of giving up: a few hundred dollars in many cases. Those who design these systems know their market, and it’s a profitable one.

The ransomware that has affected systems in more than 150 countries recently, WannaCry, made press headlines last week, but it doesn’t seem to be more virulent or more expensive than other ransomware. This one has a particularly interesting pedigree: It’s based on a vulnerability developed by the National Security Agency that can be used against many versions of the Windows operating system. The NSA’s code was, in turn, stolen by an unknown hacker group called Shadow Brokers widely believed by the security community to be the Russians in 2014 and released to the public in April.

Microsoft patched the vulnerability a month earlier, presumably after being alerted by the NSA that the leak was imminent. But the vulnerability affected older versions of Windows that Microsoft no longer supports, and there are still many people and organizations that don’t regularly patch their systems. This allowed whoever wrote WannaCry —it could be anyone from a lone individual to an organized crime syndicate—to use it to infect computers and extort users.

The lessons for users are obvious: Keep your system patches up to date and regularly backup your data. This isn’t just good advice to defend against ransomware, but good advice in general. But it’s becoming obsolete.

Everything is becoming a computer. Your microwave is a computer that makes things hot. Your refrigerator is a computer that keeps things cold. Your car and television, the traffic lights and signals in your city and our national power grid are all computers. This is the much-hyped Internet of Things (IoT). It’s coming, and it’s coming faster than you might think. And as these devices connect to the Internet, they become vulnerable to ransomware and other computer threats.

It’s only a matter of time before people get messages on their car screens saying that the engine has been disabled and it will cost $200 in bitcoin to turn it back on. Or a similar message on their phones about their Internet-enabled door lock: Pay $100 if you want to get into your house tonight. Or pay far more if they want their embedded heart defibrillator to keep working.

This isn’t just theoretical. Researchers have already demonstrated a ransomware attack against smart thermostats, which may sound like a nuisance at first but can cause serious property damage if it’s cold enough outside. If the device under attack has no screen, you’ll get the message on the smartphone app you control it from.

Hackers don’t even have to come up with these ideas on their own; the government agencies whose code was stolen were already doing it. One of the leaked CIA attack tools targets Internet-enabled Samsung smart televisions.

Even worse, the usual solutions won’t work with these embedded systems. You have no way to back up your refrigerator’s software, and it’s unclear whether that solution would even work if an attack targets the functionality of the device rather than its stored data.

These devices will be around for a long time. Unlike our phones and computers, which we replace every few years, cars are expected to last at least a decade. We want our appliances to run for 20 years or more, our thermostats even longer.

What happens when the company that made our smart washing machine—or just the computer part—goes out of business, or otherwise decides that they can no longer support older models? WannaCry affected Windows versions as far back as XP, a version that Microsoft no longer supports. The company broke with policy and released a patch for those older systems, but it has both the engineering talent and the money to do so.

That won’t happen with low-cost IoT devices.

Those devices are built on the cheap, and the companies that make them don’t have the dedicated teams of security engineers ready to craft and distribute security patches. The economics of the IoT doesn’t allow for it. Even worse, many of these devices aren’t patchable. Remember last fall when the Mirai botnet infected hundreds of thousands of Internet-enabled digital video recorders, webcams and other devices and launched a massive denial-of-service attack that resulted in a host of popular websites dropping off the Internet? Most of those devices couldn’t be fixed with new software once they were attacked. The way you update your DVR is to throw it away and buy a new one.

Solutions aren’t easy and they’re not pretty. The market is not going to fix this unaided. Security is a hard-to-evaluate feature against a possible future threat, and consumers have long rewarded companies that provide easy-to-compare features and a quick time-to-market at its expense. We need to assign liabilities to companies that write insecure software that harms people, and possibly even issue and enforce regulations that require companies to maintain software systems throughout their life cycle. We may need minimum security standards for critical IoT devices. And it would help if the NSA got more involved in securing our information infrastructure and less in keeping it vulnerable so the government can eavesdrop.

I know this all sounds politically impossible right now, but we simply cannot live in a future where everything—from the things we own to our nation’s infrastructure —can be held for ransom by criminals again and again.

This essay previously appeared in the Washington Post.

Posted on May 23, 2017 at 5:55 AM • View Comments

WannaCry Ransomware

Criminals go where the money is, and cybercriminals are no exception.

And right now, the money is in ransomware.

It’s a simple scam. Encrypt the victim’s hard drive, then extract a fee to decrypt it. The scammers can’t charge too much, because they want the victim to pay rather than give up on the data. But they can charge individuals a few hundred dollars, and they can charge institutions like hospitals a few thousand. Do it at scale, and it’s a profitable business.

And scale is how ransomware works. Computers are infected automatically, with viruses that spread over the internet. Payment is no more difficult than buying something online —and payable in untraceable bitcoin -- with some ransomware makers offering tech support to those unsure of how to buy or transfer bitcoin. Customer service is important; people need to know they’ll get their files back once they pay.

And they want you to pay. If they’re lucky, they’ve encrypted your irreplaceable family photos, or the documents of a project you’ve been working on for weeks. Or maybe your company’s accounts receivable files or your hospital’s patient records. The more you need what they’ve stolen, the better.

The particular ransomware making headlines is called WannaCry, and it’s infected some pretty serious organizations.

What can you do about it? Your first line of defense is to diligently install every security update as soon as it becomes available, and to migrate to systems that vendors still support. Microsoft issued a security patch that protects against WannaCry months before the ransomware started infecting systems; it only works against computers that haven’t been patched. And many of the systems it infects are older computers, no longer normally supported by Microsoft— though it did belatedly release a patch for those older systems. I know it’s hard, but until companies are forced to maintain old systems, you’re much safer upgrading.

This is easier advice for individuals than for organizations. You and I can pretty easily migrate to a new operating system, but organizations sometimes have custom software that breaks when they change OS versions or install updates. Many of the organizations hit by WannaCry had outdated systems for exactly these reasons. But as expensive and time-consuming as updating might be, the risks of not doing so are increasing.

Your second line of defense is good antivirus software. Sometimes ransomware tricks you into encrypting your own hard drive by clicking on a file attachment that you thought was benign. Antivirus software can often catch your mistake and prevent the malicious software from running. This isn’t perfect, of course, but it’s an important part of any defense.

Your third line of defense is to diligently back up your files. There are systems that do this automatically for your hard drive. You can invest in one of those. Or you can store your important data in the cloud. If your irreplaceable family photos are in a backup drive in your house, then the ransomware has that much less hold on you. If your e-mail and documents are in the cloud, then you can just reinstall the operating system and bypass the ransomware entirely. I know storing data in the cloud has its own privacy risks, but they may be less than the risks of losing everything to ransomware.

That takes care of your computers and smartphones, but what about everything else? We’re deep into the age of the “Internet of things.”

There are now computers in your household appliances. There are computers in your cars and in the airplanes you travel on. Computers run our traffic lights and our power grids. These are all vulnerable to ransomware. The Mirai botnet exploited a vulnerability in internet-enabled devices like DVRs and webcams to launch a denial-of-service attack against a critical internet name server; next time it could just as easily disable the devices and demand payment to turn them back on.

Re-enabling a webcam will be cheap; re-enabling your car will cost more. And you don’t want to know how vulnerable implanted medical devices are to these sorts of attacks.

Commercial solutions are coming, probably a convenient repackaging of the three lines of defense described above. But it’ll be yet another security surcharge you’ll be expected to pay because the computers and internet-of-things devices you buy are so insecure. Because there are currently no liabilities for lousy software and no regulations mandating secure software, the market rewards software that’s fast and cheap at the expense of good. Until that changes, ransomware will continue to be profitable line of criminal business.

This essay previously appeared in the New York Daily News.

Posted on May 19, 2017 at 6:10 AM • View Comments

Apple's Cloud Key Vault

Ever since Ian Krstić, Apple’s Head of Security Engineering and Architecture, presented the company’s key backup technology at Black Hat 2016, people have been pointing to it as evidence that the company can create a secure backdoor for law enforcement.

It’s not. Matthew Green and Steve Bellovin have both explained why not. And the same group of us that wrote the “Keys Under Doormats” paper on why backdoors are a bad idea have also explained why Apple’s technology does not enable it to build secure backdoors for law enforcement. Michael Specter did the bulk of the writing.

The problem with Tait’s argument becomes clearer when you actually try to turn Apple’s Cloud Key Vault into an exceptional access mechanism. In that case, Apple would have to replace the HSM with one that accepts an additional message from Apple or the FBI—or an agency from any of the 100+ countries where Apple sells iPhones—saying “OK, decrypt,” as well as the user’s password. In order to do this securely, these messages would have to be cryptographically signed with a second set of keys, which would then have to be used as often as law enforcement access is required. Any exceptional access scheme made from this system would have to have an additional set of keys to ensure authorized use of the law enforcement access credentials.

Managing access by a hundred-plus countries is impractical due to mutual mistrust, so Apple would be stuck with keeping a second signing key (or database of second signing keys) for signing these messages that must be accessed for each and every law enforcement agency. This puts us back at the situation where Apple needs to protect another repeatedly-used, high-value public key infrastructure: an equivalent situation to what has already resulted in the theft of Bitcoin wallets, RealTek’s code signing keys, and Certificate Authority failures, among many other disasters.

Repeated access of private keys drastically increases their probability of theft, loss, or inappropriate use. Apple’s Cloud Key Vault does not have any Apple-owned private key, and therefore does not indicate that a secure solution to this problem actually exists.

It is worth noting that the exceptional access schemes one can create from Apple’s CKV (like the one outlined above) inherently entails the precise issues we warned about in our previous essay on the danger signs for recognizing flawed exceptional access systems. Additionally, the Risks of Key Escrow and Keys Under Doormats papers describe further technical and nontechnical issues with exceptional access schemes that must be addressed. Among the nontechnical hurdles would be the requirement, for example, that Apple run a large legal office to confirm that requests for access from the government of Uzbekistan actually involved a device that was located in that country, and that the request was consistent with both US law and Uzbek law.

My colleagues and I do not argue that the technical community doesn’t know how to store high-value encryption keys—to the contrary that’s the whole point of an HSM. Rather, we assert that holding on to keys in a safe way such that any other party (i.e. law enforcement or Apple itself) can also access them repeatedly without high potential for catastrophic loss is impossible with today’s technology, and that any scheme running into fundamental sociotechnical challenges such as jurisdiction must be evaluated honestly before any technical implementation is considered.

Posted on September 8, 2016 at 8:00 AM • View Comments

Comparing Messaging Apps

Micah Lee has a nice comparison among Signal, WhatsApp, and Allo.

In this article, I’m going to compare WhatsApp, Signal, and Allo from a privacy perspective.

While all three apps use the same secure-messaging protocol, they differ on exactly what information is encrypted, what metadata is collected, and what, precisely, is stored in the cloud - and therefore available, in theory at least, to government snoops and wily hackers.

In the end, I’m going to advocate you use Signal whenever you can - which actually may not end up being as often as you would like.

EDITED TO ADD (6/25): Don’t use Telegram.

Posted on June 23, 2016 at 6:54 AM • View Comments

Lesson in Successful Disaster Planning

I found the story of the Federal Reserve on 9/11 to be fascinating. It seems they just flipped a switch on all their Y2K preparations, and it worked.

Posted on September 23, 2014 at 1:09 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.