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Book Review: Cyber War Will Not Take Place

Thomas Rid, Cyber War Will Not Take Place, Oxford University Press, 2013.

Cyber war is possibly the most dangerous buzzword of the Internet era. The fear-inducing rhetoric surrounding it is being used to justify major changes in the way the Internet is organized, governed, and constructed. And in Cyber War Will Not Take Place, Thomas Rid convincingly argues that cyber war is not a compelling threat. Rid is one of the leading cyber war skeptics in Europe, and although he doesn’t argue that war won’t extend into cyberspace, he says that cyberspace’s role in war is more limited than doomsayers want us to believe. His argument against cyber war is lucid and methodical. He divides “offensive and violent political acts” in cyberspace into: sabotage, espionage, and subversion. These categories are larger than cyberspace, of course, but Rid spends considerable time analyzing their strengths and limitations within cyberspace. The details are complicated, but his end conclusion is that many of these types of attacks cannot be defined as acts of war, and any future war won’t involve many of these types of attacks.

None of this is meant to imply that cyberspace is safe. Threats of all sorts fill cyberspace, but not threats of war. As such, the policies to defend against them are different. While hackers and criminal threats get all the headlines, more worrisome are the threats from governments seeking to consolidate their power. I have long argued that controlling the Internet has become critical for totalitarian states, and their four broad tools of surveillance, censorship, propaganda and use control have legitimate commercial applications, and are also employed by democracies.

A lot of the problem here is of definition. There isn’t broad agreement as to what constitutes cyber war, and this confusion plays into the hands of those hyping its threat. If everything from Chinese espionage to Russian criminal extortion to activist disruption falls under the cyber war umbrella, then it only makes sense to put more of the Internet under government—and thus military—control. Rid’s book is a compelling counter-argument to this approach.

Rid’s final chapter is an essay unto itself, and lays out his vision as to how we should deal with threats in cyberspace. For policymakers who won’t sit through an entire book, this is the chapter I would urge them to read. Arms races are dangerous and destabilizing, and we’re in the early years of a cyber war arms race that’s being fueled by fear and ignorance. This book is a cogent counterpoint to the doomsayers and the profiteers, and should be required reading for anyone concerned about security in cyberspace.

This book review previously appeared in Europe’s World.

Posted on October 25, 2013 at 9:26 AM • View Comments

Defending Against Crypto Backdoors

We already know the NSA wants to eavesdrop on the Internet. It has secret agreements with telcos to get direct access to bulk Internet traffic. It has massive systems like TUMULT, TURMOIL, and TURBULENCE to sift through it all. And it can identify ciphertext—encrypted information—and figure out which programs could have created it.

But what the NSA wants is to be able to read that encrypted information in as close to real-time as possible. It wants backdoors, just like the cybercriminals and less benevolent governments do.

And we have to figure out how to make it harder for them, or anyone else, to insert those backdoors.

How the NSA Gets Its Backdoors

The FBI tried to get backdoor access embedded in an AT&T secure telephone system in the mid-1990s. The Clipper Chip included something called a LEAF: a Law Enforcement Access Field. It was the key used to encrypt the phone conversation, itself encrypted in a special key known to the FBI, and it was transmitted along with the phone conversation. An FBI eavesdropper could intercept the LEAF and decrypt it, then use the data to eavesdrop on the phone call.

But the Clipper Chip faced severe backlash, and became defunct a few years after being announced.

Having lost that public battle, the NSA decided to get its backdoors through subterfuge: by asking nicely, pressuring, threatening, bribing, or mandating through secret order. The general name for this program is BULLRUN.

Defending against these attacks is difficult. We know from subliminal channel and kleptography research that it’s pretty much impossible to guarantee that a complex piece of software isn’t leaking secret information. We know from Ken Thompson’s famous talk on “trusting trust” (first delivered in the ACM Turing Award Lectures) that you can never be totally sure if there’s a security flaw in your software.

Since BULLRUN became public last month, the security community has been examining security flaws discovered over the past several years, looking for signs of deliberate tampering. The Debian random number flaw was probably not deliberate, but the 2003 Linux security vulnerability probably was. The DUAL_EC_DRBG random number generator may or may not have been a backdoor. The SSL 2.0 flaw was probably an honest mistake. The GSM A5/1 encryption algorithm was almost certainly deliberately weakened. All the common RSA moduli out there in the wild: we don’t know. Microsoft’s _NSAKEY looks like a smoking gun, but honestly, we don’t know.

How the NSA Designs Backdoors

While a separate program that sends our data to some IP address somewhere is certainly how any hacker—from the lowliest script kiddie up to the NSA—spies on our computers, it’s too labor-intensive to work in the general case.

For government eavesdroppers like the NSA, subtlety is critical. In particular, three characteristics are important:

Low discoverability. The less the backdoor affects the normal operations of the program, the better. Ideally, it shouldn’t affect functionality at all. The smaller the backdoor is, the better. Ideally, it should just look like normal functional code. As a blatant example, an email encryption backdoor that appends a plaintext copy to the encrypted copy is much less desirable than a backdoor that reuses most of the key bits in a public IV (initialization vector).
High deniability. If discovered, the backdoor should look like a mistake. It could be a single opcode change. Or maybe a “mistyped” constant. Or “accidentally” reusing a single-use key multiple times. This is the main reason I am skeptical about _NSAKEY as a deliberate backdoor, and why so many people don’t believe the DUAL_EC_DRBG backdoor is real: they’re both too obvious.
Minimal conspiracy. The more people who know about the backdoor, the more likely the secret is to get out. So any good backdoor should be known to very few people. That’s why the recently described potential vulnerability in Intel’s random number generator worries me so much; one person could make this change during mask generation, and no one else would know.

These characteristics imply several things:

A closed-source system is safer to subvert, because an open-source system comes with a greater risk of that subversion being discovered. On the other hand, a big open-source system with a lot of developers and sloppy version control is easier to subvert.
If a software system only has to interoperate with itself, then it is easier to subvert. For example, a closed VPN encryption system only has to interoperate with other instances of that same proprietary system. This is easier to subvert than an industry-wide VPN standard that has to interoperate with equipment from other vendors.
A commercial software system is easier to subvert, because the profit motive provides a strong incentive for the company to go along with the NSA’s requests.
Protocols developed by large open standards bodies are harder to influence, because a lot of eyes are paying attention. Systems designed by closed standards bodies are easier to influence, especially if the people involved in the standards don’t really understand security.
Systems that send seemingly random information in the clear are easier to subvert. One of the most effective ways of subverting a system is by leaking key information—recall the LEAF—and modifying random nonces or header information is the easiest way to do that.

Design Strategies for Defending against Backdoors

With these principles in mind, we can list design strategies. None of them is foolproof, but they are all useful. I’m sure there’s more; this list isn’t meant to be exhaustive, nor the final word on the topic. It’s simply a starting place for discussion. But it won’t work unless customers start demanding software with this sort of transparency.

Vendors should make their encryption code public, including the protocol specifications. This will allow others to examine the code for vulnerabilities. It’s true we won’t know for sure if the code we’re seeing is the code that’s actually used in the application, but surreptitious substitution is hard to do, forces the company to outright lie, and increases the number of people required for the conspiracy to work.
The community should create independent compatible versions of encryption systems, to verify they are operating properly. I envision companies paying for these independent versions, and universities accepting this sort of work as good practice for their students. And yes, I know this can be very hard in practice.
There should be no master secrets. These are just too vulnerable.
All random number generators should conform to published and accepted standards. Breaking the random number generator is the easiest difficult-to-detect method of subverting an encryption system. A corollary: we need better published and accepted RNG standards.
Encryption protocols should be designed so as not to leak any random information. Nonces should be considered part of the key or public predictable counters if possible. Again, the goal is to make it harder to subtly leak key bits in this information.

This is a hard problem. We don’t have any technical controls that protect users from the authors of their software.

And the current state of software makes the problem even harder: Modern apps chatter endlessly on the Internet, providing noise and cover for covert communications. Feature bloat provides a greater “attack surface” for anyone wanting to install a backdoor.

In general, what we need is assurance: methodologies for ensuring that a piece of software does what it’s supposed to do and nothing more. Unfortunately, we’re terrible at this. Even worse, there’s not a lot of practical research in this area—and it’s hurting us badly right now.

Yes, we need legal prohibitions against the NSA trying to subvert authors and deliberately weaken cryptography. But this isn’t just about the NSA, and legal controls won’t protect against those who don’t follow the law and ignore international agreements. We need to make their job harder by increasing their risk of discovery. Against a risk-averse adversary, it might be good enough.

This essay previously appeared on Wired.com.

EDITED TO ADD: I am looking for other examples of known or plausible instances of intentional vulnerabilities for a paper I am writing on this topic. If you can think of an example, please post a description and reference in the comments below. Please explain why you think the vulnerability could be intentional. Thank you.

Posted on October 22, 2013 at 6:15 AM • View Comments

The Trajectories of Government and Corporate Surveillance

Historically, surveillance was difficult and expensive.

Over the decades, as technology advanced, surveillance became easier and easier. Today, we find ourselves in a world of ubiquitous surveillance, where everything is collected, saved, searched, correlated and analyzed.

But while technology allowed for an increase in both corporate and government surveillance, the private and public sectors took very different paths to get there. The former always collected information about everyone, but over time, collected more and more of it, while the latter always collected maximal information, but over time, collected it on more and more people.

Corporate surveillance has been on a path from minimal to maximal information. Corporations always collected information on everyone they could, but in the past they didn’t collect very much of it and only held it as long as necessary. When surveillance information was expensive to collect and store, companies made do with as little as possible.

Telephone companies collected long-distance calling information because they needed it for billing purposes. Credit cards collected only the information about their customers’ transactions that they needed for billing. Stores hardly ever collected information about their customers, maybe some personal preferences, or name-and-address for advertising purposes. Even Google, back in the beginning, collected far less information about its users than it does today.

As technology improved, corporations were able to collect more. As the cost of data storage became cheaper, they were able to save more data and for a longer time. And as big data analysis tools became more powerful, it became profitable to save more. Today, almost everything is being saved by someone—probably forever.

Examples are everywhere. Internet companies like Google, Facebook, Amazon and Apple collect everything we do online at their sites. Third-party cookies allow those companies, and others, to collect data on us wherever we are on the Internet. Store affinity cards allow merchants to track our purchases. CCTV and aerial surveillance combined with automatic face recognition allow companies to track our movements; so does your cell phone. The Internet will facilitate even more surveillance, by more corporations for more purposes.

On the government side, surveillance has been on a path from individually targeted to broadly collected. When surveillance was manual and expensive, it could only be justified in extreme cases. The warrant process limited police surveillance, and resource restraints and the risk of discovery limited national intelligence surveillance. Specific individuals were targeted for surveillance, and maximal information was collected on them alone.

As technology improved, the government was able to implement ever-broadening surveillance. The National Security Agency could surveil groups—the Soviet government, the Chinese diplomatic corps, etc.—not just individuals. Eventually, they could spy on entire communications trunks.

Now, instead of watching one person, the NSA can monitor “three hops” away from that person—an ever widening network of people not directly connected to the person under surveillance. Using sophisticated tools, the NSA can surveil broad swaths of the Internet and phone network.

Governments have always used their authority to piggyback on corporate surveillance. Why should they go through the trouble of developing their own surveillance programs when they could just ask corporations for the data? For example we just learned that the NSA collects e-mail, IM and social networking contact lists for millions of Internet users worldwide.

But as corporations started collecting more information on populations, governments started demanding that data. Through National Security Letters, the FBI can surveil huge groups of people without obtaining a warrant. Through secret agreements, the NSA can monitor the entire Internet and telephone networks.

This is a huge part of the public-private surveillance partnership.

The result of all this is we’re now living in a world where both corporations and governments have us all under pretty much constant surveillance.

Data is a byproduct of the information society. Every interaction we have with a computer creates a transaction record, and we interact with computers hundreds of times a day. Even if we don’t use a computer—buying something in person with cash, say—the merchant uses a computer, and the data flows into the same system. Everything we do leaves a data shadow, and that shadow is constantly under surveillance.

Data is also a byproduct of information society socialization, whether it be e-mail, instant messages or conversations on Facebook. Conversations that used to be ephemeral are now recorded, and we are all leaving digital footprints wherever we go.

Moore’s law has made computing cheaper. All of us have made computing ubiquitous. And because computing produces data, and that data equals surveillance, we have created a world of ubiquitous surveillance.

Now we need to figure out what to do about it. This is more than reining in the NSA or fining a corporation for the occasional data abuse. We need to decide whether our data is a shared societal resource, a part of us that is inherently ours by right, or a private good to be bought and sold.

Writing in the Guardian, Chris Huhn said that “information is power, and the necessary corollary is that privacy is freedom.” How this interplay between power and freedom play out in the information age is still to be determined.

This essay previously appeared on CNN.com.

EDITED TO ADD (11/14): Richard Stallman’s comments on the subject.

Posted on October 21, 2013 at 6:05 AM • View Comments

Air Gaps

Since I started working with Snowden’s documents, I have been using a number of tools to try to stay secure from the NSA. The advice I shared included using Tor, preferring certain cryptography over others, and using public-domain encryption wherever possible.

I also recommended using an air gap, which physically isolates a computer or local network of computers from the Internet. (The name comes from the literal gap of air between the computer and the Internet; the word predates wireless networks.)

But this is more complicated than it sounds, and requires explanation.

Since we know that computers connected to the Internet are vulnerable to outside hacking, an air gap should protect against those attacks. There are a lot of systems that use—or should use—air gaps: classified military networks, nuclear power plant controls, medical equipment, avionics, and so on.

Osama Bin Laden used one. I hope human rights organizations in repressive countries are doing the same.

Air gaps might be conceptually simple, but they’re hard to maintain in practice. The truth is that nobody wants a computer that never receives files from the Internet and never sends files out into the Internet. What they want is a computer that’s not directly connected to the Internet, albeit with some secure way of moving files on and off.

But every time a file moves back or forth, there’s the potential for attack.

And air gaps have been breached. Stuxnet was a US and Israeli military-grade piece of malware that attacked the Natanz nuclear plant in Iran. It successfully jumped the air gap and penetrated the Natanz network. Another piece of malware named agent.btz, probably Chinese in origin, successfully jumped the air gap protecting US military networks.

These attacks work by exploiting security vulnerabilities in the removable media used to transfer files on and off the air-gapped computers.

Since working with Snowden’s NSA files, I have tried to maintain a single air-gapped computer. It turned out to be harder than I expected, and I have ten rules for anyone trying to do the same:

When you set up your computer, connect it to the Internet as little as possible. It’s impossible to completely avoid connecting the computer to the Internet, but try to configure it all at once and as anonymously as possible. I purchased my computer off-the-shelf in a big box store, then went to a friend’s network and downloaded everything I needed in a single session. (The ultra-paranoid way to do this is to buy two identical computers, configure one using the above method, upload the results to a cloud-based anti-virus checker, and transfer the results of that to the air gap machine using a one-way process.)
Install the minimum software set you need to do your job, and disable all operating system services that you won’t need. The less software you install, the less an attacker has available to exploit. I downloaded and installed OpenOffice, a PDF reader, a text editor, TrueCrypt, and BleachBit. That’s all. (No, I don’t have any inside knowledge about TrueCrypt, and there’s a lot about it that makes me suspicious. But for Windows full-disk encryption it’s that, Microsoft’s BitLocker, or Symantec’s PGPDisk—and I am more worried about large US corporations being pressured by the NSA than I am about TrueCrypt.)
Once you have your computer configured, never directly connect it to the Internet again. Consider physically disabling the wireless capability, so it doesn’t get turned on by accident.
If you need to install new software, download it anonymously from a random network, put it on some removable media, and then manually transfer it to the air-gapped computer. This is by no means perfect, but it’s an attempt to make it harder for the attacker to target your computer.
Turn off all autorun features. This should be standard practice for all the computers you own, but it’s especially important for an air-gapped computer. Agent.btz used autorun to infect US military computers.
Minimize the amount of executable code you move onto the air-gapped computer. Text files are best. Microsoft Office files and PDFs are more dangerous, since they might have embedded macros. Turn off all macro capabilities you can on the air-gapped computer. Don’t worry too much about patching your system; in general, the risk of the executable code is worse than the risk of not having your patches up to date. You’re not on the Internet, after all.
Only use trusted media to move files on and off air-gapped computers. A USB stick you purchase from a store is safer than one given to you by someone you don’t know—or one you find in a parking lot.
For file transfer, a writable optical disk (CD or DVD) is safer than a USB stick. Malware can silently write data to a USB stick, but it can’t spin the CD-R up to 1000 rpm without your noticing. This means that the malware can only write to the disk when you write to the disk. You can also verify how much data has been written to the CD by physically checking the back of it. If you’ve only written one file, but it looks like three-quarters of the CD was burned, you have a problem. Note: the first company to market a USB stick with a light that indicates a write operation—not read or write; I’ve got one of those—wins a prize.
When moving files on and off your air-gapped computer, use the absolute smallest storage device you can. And fill up the entire device with random files. If an air-gapped computer is compromised, the malware is going to try to sneak data off it using that media. While malware can easily hide stolen files from you, it can’t break the laws of physics. So if you use a tiny transfer device, it can only steal a very small amount of data at a time. If you use a large device, it can take that much more. Business-card-sized mini-CDs can have capacity as low as 30 MB. I still see 1-GB USB sticks for sale.
Consider encrypting everything you move on and off the air-gapped computer. Sometimes you’ll be moving public files and it won’t matter, but sometimes you won’t be, and it will. And if you’re using optical media, those disks will be impossible to erase. Strong encryption solves these problems. And don’t forget to encrypt the computer as well; whole-disk encryption is the best.

One thing I didn’t do, although it’s worth considering, is use a stateless operating system like Tails. You can configure Tails with a persistent volume to save your data, but no operating system changes are ever saved. Booting Tails from a read-only DVD—you can keep your data on an encrypted USB stick—is even more secure. Of course, this is not foolproof, but it greatly reduces the potential avenues for attack.

Yes, all this is advice for the paranoid. And it’s probably impossible to enforce for any network more complicated than a single computer with a single user. But if you’re thinking about setting up an air-gapped computer, you already believe that some very powerful attackers are after you personally. If you’re going to use an air gap, use it properly.

Of course you can take things further. I have met people who have physically removed the camera, microphone, and wireless capability altogether. But that’s too much paranoia for me right now.

This essay previously appeared on Wired.com.

EDITED TO ADD: Yes, I am ignoring TEMPEST attacks. I am also ignoring black bag attacks against my home.

Posted on October 11, 2013 at 6:45 AM • View Comments

The NSA's New Risk Analysis

As I recently reported in the Guardian, the NSA has secret servers on the Internet that hack into other computers, codename FOXACID. These servers provide an excellent demonstration of how the NSA approaches risk management, and exposes flaws in how the agency thinks about the secrecy of its own programs.

Here are the FOXACID basics: By the time the NSA tricks a target into visiting one of those servers, it already knows exactly who that target is, who wants him eavesdropped on, and the expected value of the data it hopes to receive. Based on that information, the server can automatically decide what exploit to serve the target, taking into account the risks associated with attacking the target, as well as the benefits of a successful attack. According to a top-secret operational procedures manual provided by Edward Snowden, an exploit named Validator might be the default, but the NSA has a variety of options. The documentation mentions United Rake, Peddle Cheap, Packet Wrench, and Beach Head—all delivered from a FOXACID subsystem called Ferret Cannon. Oh how I love some of these code names. (On the other hand, EGOTISTICALGIRAFFE has to be the dumbest code name ever.)

Snowden explained this to Guardian reporter Glenn Greenwald in Hong Kong. If the target is a high-value one, FOXACID might run a rare zero-day exploit that it developed or purchased. If the target is technically sophisticated, FOXACID might decide that there’s too much chance for discovery, and keeping the zero-day exploit a secret is more important. If the target is a low-value one, FOXACID might run an exploit that’s less valuable. If the target is low-value and technically sophisticated, FOXACID might even run an already-known vulnerability.

We know that the NSA receives advance warning from Microsoft of vulnerabilities that will soon be patched; there’s not much of a loss if an exploit based on that vulnerability is discovered. FOXACID has tiers of exploits it can run, and uses a complicated trade-off system to determine which one to run against any particular target.

This cost-benefit analysis doesn’t end at successful exploitation. According to Snowden, the TAO—that’s Tailored Access Operations—operators running the FOXACID system have a detailed flowchart, with tons of rules about when to stop. If something doesn’t work, stop. If they detect a PSP, a personal security product, stop. If anything goes weird, stop. This is how the NSA avoids detection, and also how it takes mid-level computer operators and turn them into what they call “cyberwarriors.” It’s not that they’re skilled hackers, it’s that the procedures do the work for them.

And they’re super cautious about what they do.

While the NSA excels at performing this cost-benefit analysis at the tactical level, it’s far less competent at doing the same thing at the policy level. The organization seems to be good enough at assessing the risk of discovery—for example, if the target of an intelligence-gathering effort discovers that effort—but to have completely ignored the risks of those efforts becoming front-page news.

It’s not just in the U.S., where newspapers are heavy with reports of the NSA spying on every Verizon customer, spying on domestic e-mail users, and secretly working to cripple commercial cryptography systems, but also around the world, most notably in Brazil, Belgium, and the European Union. All of these operations have caused significant blowback—for the NSA, for the U.S., and for the Internet as a whole.

The NSA spent decades operating in almost complete secrecy, but those days are over. As the corporate world learned years ago, secrets are hard to keep in the information age, and openness is a safer strategy. The tendency to classify everything means that the NSA won’t be able to sort what really needs to remain secret from everything else. The younger generation is more used to radical transparency than secrecy, and is less invested in the national security state. And whistleblowing is the civil disobedience of our time.

At this point, the NSA has to assume that all of its operations will become public, probably sooner than it would like. It has to start taking that into account when weighing the costs and benefits of those operations. And it now has to be just as cautious about new eavesdropping operations as it is about using FOXACID exploits attacks against users.

This essay previously appeared in the Atlantic.

Posted on October 9, 2013 at 6:28 AM • View Comments

Why It's Important to Publish the NSA Programs

The Guardian recently reported on how the NSA targets Tor users, along with details of how it uses centrally placed servers on the Internet to attack individual computers. This builds on a Brazilian news story from a mid-September that, in part, shows that the NSA is impersonating Google servers to users; a German story on how the NSA is hacking into smartphones; and a Guardian story from early September on how the NSA is deliberately weakening common security algorithms, protocols, and products.

The common thread among these stories is that the NSA is subverting the Internet and turning it into a massive surveillance tool. The NSA’s actions are making us all less safe, because its eavesdropping mission is degrading its ability to protect the US.

Among IT security professionals, it has been long understood that the public disclosure of vulnerabilities is the only consistent way to improve security. That’s why researchers publish information about vulnerabilities in computer software and operating systems, cryptographic algorithms, and consumer products like implantable medical devices, cars, and CCTV cameras.

It wasn’t always like this. In the early years of computing, it was common for security researchers to quietly alert the product vendors about vulnerabilities, so they could fix them without the “bad guys” learning about them. The problem was that the vendors wouldn’t bother fixing them, or took years before getting around to it. Without public pressure, there was no rush.

This all changed when researchers started publishing. Now vendors are under intense public pressure to patch vulnerabilities as quickly as possible. The majority of security improvements in the hardware and software we all use today is a result of this process. This is why Microsoft’s Patch Tuesday process fixes so many vulnerabilities every month. This is why Apple’s iPhone is designed so securely. This is why so many products push out security updates so often. And this is why mass-market cryptography has continually improved. Without public disclosure, you’d be much less secure against cybercriminals, hacktivists, and state-sponsored cyberattackers.

The NSA’s actions turn that process on its head, which is why the security community is so incensed. The NSA not only develops and purchases vulnerabilities, but deliberately creates them through secret vendor agreements. These actions go against everything we know about improving security on the Internet.

It’s folly to believe that any NSA hacking technique will remain secret for very long. Yes, the NSA has a bigger research effort than any other institution, but there’s a lot of research being done—by other governments in secret, and in academic and hacker communities in the open. These same attacks are being used by other governments. And technology is fundamentally democratizing: today’s NSA secret techniques are tomorrow’s PhD theses and the following day’s cybercrime attack tools.

It’s equal folly to believe that the NSA’s secretly installed backdoors will remain secret. Given how inept the NSA was at protecting its own secrets, it’s extremely unlikely that Edward Snowden was the first sysadmin contractor to walk out the door with a boatload of them. And the previous leakers could have easily been working for a foreign government. But it wouldn’t take a rogue NSA employee; researchers or hackers could discover any of these backdoors on their own.

This isn’t hypothetical. We already know of government-mandated backdoors being used by criminals in Greece, Italy, and elsewhere. We know China is actively engaging in cyber-espionage worldwide. A recent Economist article called it “akin to a government secretly commanding lockmakers to make their products easier to pick—and to do so amid an epidemic of burglary.”

The NSA has two conflicting missions. Its eavesdropping mission has been getting all the headlines, but it also has a mission to protect US military and critical infrastructure communications from foreign attack. Historically, these two missions have not come into conflict. During the cold war, for example, we would defend our systems and attack Soviet systems.

But with the rise of mass-market computing and the Internet, the two missions have become interwoven. It becomes increasingly difficult to attack their systems and defend our systems, because everything is using the same systems: Microsoft Windows, Cisco routers, HTML, TCP/IP, iPhones, Intel chips, and so on. Finding a vulnerability—or creating one—and keeping it secret to attack the bad guys necessarily leaves the good guys more vulnerable.

Far better would be for the NSA to take those vulnerabilities back to the vendors to patch. Yes, it would make it harder to eavesdrop on the bad guys, but it would make everyone on the Internet safer. If we believe in protecting our critical infrastructure from foreign attack, if we believe in protecting Internet users from repressive regimes worldwide, and if we believe in defending businesses and ourselves from cybercrime, then doing otherwise is lunacy.

It is important that we make the NSA’s actions public in sufficient detail for the vulnerabilities to be fixed. It’s the only way to force change and improve security.

This essay previously appeared in the Guardian.

Posted on October 8, 2013 at 6:44 AM • View Comments

How the NSA Attacks Tor/Firefox Users With QUANTUM and FOXACID

The online anonymity network Tor is a high-priority target for the National Security Agency. The work of attacking Tor is done by the NSA‘s application vulnerabilities branch, which is part of the systems intelligence directorate, or SID. The majority of NSA employees work in SID, which is tasked with collecting data from communications systems around the world.

According to a top-secret NSA presentation provided by the whistleblower Edward Snowden, one successful technique the NSA has developed involves exploiting the Tor browser bundle, a collection of programs designed to make it easy for people to install and use the software. The trick identifies Tor users on the Internet and then executes an attack against their Firefox web browser.

The NSA refers to these capabilities as CNE, or computer network exploitation.

The first step of this process is finding Tor users. To accomplish this, the NSA relies on its vast capability to monitor large parts of the Internet. This is done via the agency’s partnership with US telecoms firms under programs codenamed Stormbrew, Fairview, Oakstar and Blarney.

The NSA creates “fingerprints” that detect HTTP requests from the Tor network to particular servers. These fingerprints are loaded into NSA database systems like XKeyscore, a bespoke collection and analysis tool that NSA boasts allows its analysts to see “almost everything” a target does on the Internet.

Using powerful data analysis tools with codenames such as Turbulence, Turmoil and Tumult, the NSA automatically sifts through the enormous amount of Internet traffic that it sees, looking for Tor connections.

Last month, Brazilian TV news show Fantastico showed screenshots of an NSA tool that had the ability to identify Tor users by monitoring Internet traffic.

The very feature that makes Tor a powerful anonymity service, and the fact that all Tor users look alike on the Internet, makes it easy to differentiate Tor users from other web users. On the other hand, the anonymity provided by Tor makes it impossible for the NSA to know who the user is, or whether or not the user is in the US.

After identifying an individual Tor user on the Internet, the NSA uses its network of secret Internet servers to redirect those users to another set of secret Internet servers, with the codename FoxAcid, to infect the user’s computer. FoxAcid is an NSA system designed to act as a matchmaker between potential targets and attacks developed by the NSA, giving the agency opportunity to launch prepared attacks against their systems.

Once the computer is successfully attacked, it secretly calls back to a FoxAcid server, which then performs additional attacks on the target computer to ensure that it remains compromised long-term, and continues to provide eavesdropping information back to the NSA.

Exploiting the Tor browser bundle

Tor is a well-designed and robust anonymity tool, and successfully attacking it is difficult. The NSA attacks we found individually target Tor users by exploiting vulnerabilities in their Firefox browsers, and not the Tor application directly.

This, too, is difficult. Tor users often turn off vulnerable services like scripts and Flash when using Tor, making it difficult to target those services. Even so, the NSA uses a series of native Firefox vulnerabilities to attack users of the Tor browser bundle.

According to the training presentation provided by Snowden, EgotisticalGiraffe exploits a type confusion vulnerability in E4X, which is an XML extension for JavaScript. This vulnerability exists in Firefox 11.0—16.0.2, as well as Firefox 10.0 ESR—the Firefox version used until recently in the Tor browser bundle. According to another document, the vulnerability exploited by EgotisticalGiraffe was inadvertently fixed when Mozilla removed the E4X library with the vulnerability, and when Tor added that Firefox version into the Tor browser bundle, but NSA were confident that they would be able to find a replacement Firefox exploit that worked against version 17.0 ESR.

The Quantum system

To trick targets into visiting a FoxAcid server, the NSA relies on its secret partnerships with US telecoms companies. As part of the Turmoil system, the NSA places secret servers, codenamed Quantum, at key places on the Internet backbone. This placement ensures that they can react faster than other websites can. By exploiting that speed difference, these servers can impersonate a visited website to the target before the legitimate website can respond, thereby tricking the target’s browser to visit a Foxacid server.

In the academic literature, these are called “man-in-the-middle” attacks, and have been known to the commercial and academic security communities. More specifically, they are examples of “man-on-the-side” attacks.

They are hard for any organization other than the NSA to reliably execute, because they require the attacker to have a privileged position on the Internet backbone, and exploit a “race condition” between the NSA server and the legitimate website. This top-secret NSA diagram, made public last month, shows a Quantum server impersonating Google in this type of attack.

The NSA uses these fast Quantum servers to execute a packet injection attack, which surreptitiously redirects the target to the FoxAcid server. An article in the German magazine Spiegel, based on additional top secret Snowden documents, mentions an NSA developed attack technology with the name of QuantumInsert that performs redirection attacks. Another top-secret Tor presentation provided by Snowden mentions QuantumCookie to force cookies onto target browsers, and another Quantum program to “degrade/deny/disrupt Tor access”.

This same technique is used by the Chinese government to block its citizens from reading censored Internet content, and has been hypothesized as a probable NSA attack technique.

The FoxAcid system

According to various top-secret documents provided by Snowden, FoxAcid is the NSA codename for what the NSA calls an “exploit orchestrator,” an Internet-enabled system capable of attacking target computers in a variety of different ways. It is a Windows 2003 computer configured with custom software and a series of Perl scripts. These servers are run by the NSA’s tailored access operations, or TAO, group. TAO is another subgroup of the systems intelligence directorate.

The servers are on the public Internet. They have normal-looking domain names, and can be visited by any browser from anywhere; ownership of those domains cannot be traced back to the NSA.

However, if a browser tries to visit a FoxAcid server with a special URL, called a FoxAcid tag, the server attempts to infect that browser, and then the computer, in an effort to take control of it. The NSA can trick browsers into using that URL using a variety of methods, including the race-condition attack mentioned above and frame injection attacks.

FoxAcid tags are designed to look innocuous, so that anyone who sees them would not be suspicious. http://baseball2.2ndhalfplays.com/nested/attribs/bins/1/define/forms9952_z1zzz.html is an example of one such tag, given in another top-secret training presentation provided by Snowden.

There is no currently registered domain name by that name; it is just an example for internal NSA training purposes.

The training material states that merely trying to visit the homepage of a real FoxAcid server will not result in any attack, and that a specialized URL is required. This URL would be created by TAO for a specific NSA operation, and unique to that operation and target. This allows the FoxAcid server to know exactly who the target is when his computer contacts it.

According to Snowden, FoxAcid is a general CNE system, used for many types of attacks other than the Tor attacks described here. It is designed to be modular, with flexibility that allows TAO to swap and replace exploits if they are discovered, and only run certain exploits against certain types of targets.

The most valuable exploits are saved for the most important targets. Low-value exploits are run against technically sophisticated targets where the chance of detection is high. TAO maintains a library of exploits, each based on a different vulnerability in a system. Different exploits are authorized against different targets, depending on the value of the target, the target’s technical sophistication, the value of the exploit, and other considerations.

In the case of Tor users, FoxAcid might use EgotisticalGiraffe against their Firefox browsers.

According to a top-secret operational management procedures manual provided by Snowden, once a target is successfully exploited it is infected with one of several payloads. Two basic payloads mentioned in the manual are designed to collect configuration and location information from the target computer so an analyst can determine how to further infect the computer.

These decisions are made in part by the technical sophistication of the target and the security software installed on the target computer, called Personal Security Products or PSP, in the manual.

FoxAcid payloads are updated regularly by TAO. For example, the manual refers to version 8.2.1.1 of one of them.

FoxAcid servers also have sophisticated capabilities to avoid detection and to ensure successful infection of its targets. The operations manual states that a FoxAcid payload with the codename DireScallop can circumvent commercial products that prevent malicious software from making changes to a system that survive a reboot process.

The NSA also uses phishing attacks to induce users to click on FoxAcid tags.

TAO additionally uses FoxAcid to exploit callbacks—which is the general term for a computer infected by some automatic means—calling back to the NSA for more instructions and possibly to upload data from the target computer.

According to a top-secret operational management procedures manual, FoxAcid servers configured to receive callbacks are codenamed FrugalShot. After a callback, the FoxAcid server may run more exploits to ensure that the target computer remains compromised long term, as well as install “implants” designed to exfiltrate data.

By 2008, the NSA was getting so much FoxAcid callback data that they needed to build a special system to manage it all.

This essay previously appeared in the Guardian. It is the technical article associated with this more general-interest article. I also wrote two commentaries on the material.

EDITED TO ADD: Here is the source material we published. The Washington Post published its own story independently, based on some of the same source material and some new source material.

Here’s the official US government response to the story.

The Guardian decided to change the capitalization of the NSA codenames. They should properly be in all caps: FOXACID, QUANTUMCOOKIE, EGOTISTICALGIRAFFE, TURMOIL, and so on.

This is the relevant quote from the Spiegel article:

According to the slides in the GCHQ presentation, the attack was directed at several Belgacom employees and involved the planting of a highly developed attack technology referred to as a “Quantum Insert” (“QI”). It appears to be a method with which the person being targeted, without their knowledge, is redirected to websites that then plant malware on their computers that can then manipulate them. Some of the employees whose computers were infiltrated had “good access” to important parts of Belgacom’s infrastructure, and this seemed to please the British spies, according to the slides.

That should be “QUANTUMINSERT.” This is getting frustrating. The NSA really should release a style guide for press organizations publishing their secrets.

And the URL in the essay (now redacted at the Guardian site) was registered within minutes of the story posting, and is being used to serve malware. Don’t click on it.

Posted on October 7, 2013 at 6:24 AM • View Comments

The Limitations of Intelligence

We recently learned that US intelligence agencies had at least three days’ warning that Syrian President Bashar al-Assad was preparing to launch a chemical attack on his own people, but wasn’t able to stop it. At least that’s what an intelligence briefing from the White House reveals. With the combined abilities of our national intelligence apparatus—the CIA, NSA, National Reconnaissance Office and all the rest—it’s not surprising that we had advance notice. It’s not known whether the US shared what it knew.

More interestingly, the US government did not choose to act on that knowledge (for example, launch a preemptive strike), which left some wondering why.

There are several possible explanations, all of which point to a fundamental problem with intelligence information and our national intelligence apparatuses.

The first possibility is that we may have had the data, but didn’t fully understand what it meant. This is the proverbial connect-the-dots problem. As we’ve learned again and again, connecting the dots is hard. Our intelligence services collect billions of individual pieces of data every day. After the fact, it’s easy to walk backward through the data and notice all the individual pieces that point to what actually happened. Before the fact, though, it’s much more difficult. The overwhelming majority of those bits of data point in random directions, or nowhere at all. Almost all the dots don’t connect to anything.

Rather than thinking of intelligence as a connect-the-dots picture, think of it as a million unnumbered pictures superimposed on top of each other. Which picture is the relevant one? We have no idea. Turning that data into actual information is an extraordinarily difficult problem, and one that the vast scope of our data-gathering programs makes even more difficult.

The second possible explanation is that while we had some information about al-Assad’s plans, we didn’t have enough confirmation to act on that information. This is probably the most likely explanation. We can’t act on inklings, hunches, or possibilities. We probably can’t even act on probabilities; we have to be sure. But when it comes to intelligence, it’s hard to be sure. There could always be something else going on—something we’re not able to eavesdrop on, spy on, or see from our satellites. Again, our knowledge is most obvious after the fact.

The third is that while we were sure of our information, we couldn’t act because that would reveal “sources and methods.” This is probably the most frustrating explanation. Imagine we are able to eavesdrop on al-Assad’s most private conversations with his generals and aides, and are absolutely sure of his plans. If we act on them, we reveal that we are eavesdropping. As a result, he’s likely to change how he communicates, costing us our ability to eavesdrop. It might sound perverse, but often the fact that we are able to successfully spy on someone is a bigger secret than the information we learn from that spying.

This dynamic was vitally important during World War II. During the war, the British were able to break the German Enigma encryption machine and eavesdrop on German military communications. But while the Allies knew a lot, they would only act on information they learned when there was another plausible way they could have learned it. They even occasionally manufactured plausible explanations. It was just too risky to tip the Germans off that their encryption machines’ code had been broken.

The fourth possibility is that there was nothing useful we could have done. And it is hard to imagine how we could have prevented the use of chemical weapons in Syria. We couldn’t have launched a preemptive strike, and it’s probable that it wouldn’t have been effective. The only feasible action would be to alert the opposition—and that, too, might not have accomplished anything. Or perhaps there wasn’t sufficient agreement for any one course of action—so, by default, nothing was done.

All of these explanations point out the limitations of intelligence. The NSA serves as an example. The agency measures its success by amount of data collected, not by information synthesized or knowledge gained. But it’s knowledge that matters.

The NSA’s belief that more data is always good, and that it’s worth doing anything in order to collect it, is wrong. There are diminishing returns, and the NSA almost certainly passed that point long ago. But the idea of trade-offs does not seem to be part of its thinking.

The NSA missed the Boston Marathon bombers, even though the suspects left a really sloppy Internet trail and the older brother was on the terrorist watch list. With all the NSA is doing eavesdropping on the world, you would think the least it could manage would be keeping track of people on the terrorist watch list. Apparently not.

I don’t know how the CIA measures its success, but it failed to predict the end of the Cold War.

More data does not necessarily mean better information. It’s much easier to look backward than to predict. Information does not necessarily enable the government to act. Even when we know something, protecting the methods of collection can be more valuable than the possibility of taking action based on gathered information. But there’s not a lot of value to intelligence that can’t be used for action. These are the paradoxes of intelligence, and it’s time we started remembering them.

Of course, we need organizations like the CIA, the NSA, the NRO and all the rest. Intelligence is a vital component of national security, and can be invaluable in both wartime and peacetime. But it is just one security tool among many, and there are significant costs and limitations.

We’ve just learned from the recently leaked “black budget” that we’re spending $52 billion annually on national intelligence. We need to take a serious look at what kind of value we’re getting for our money, and whether it’s worth it.

This essay previously appeared on CNN.com.

Posted on September 17, 2013 at 6:15 AM • View Comments

Reforming the NSA

Leaks from the whistleblower Edward Snowden have catapulted the NSA into newspaper headlines and demonstrated that it has become one of the most powerful government agencies in the country. From the secret court rulings that allow it to collect data on all Americans to its systematic subversion of the entire Internet as a surveillance platform, the NSA has amassed an enormous amount of power.

There are two basic schools of thought about how this came to pass. The first focuses on the agency’s power. Like J. Edgar Hoover, NSA Director Keith Alexander has become so powerful as to be above the law. He is able to get away with what he does because neither political party—and nowhere near enough individual lawmakers—dare cross him. Longtime NSA watcher James Bamford recently quoted a CIA official: “We jokingly referred to him as Emperor Alexander—with good cause, because whatever Keith wants, Keith gets.”

Possibly the best evidence for this position is how well Alexander has weathered the Snowden leaks. The NSA’s most intimate secrets are front-page headlines, week after week. Morale at the agency is in shambles. Revelation after revelation has demonstrated that Alexander has exceeded his authority, deceived Congress, and possibly broken the law. Tens of thousands of additional top-secret documents are still waiting to come. Alexander has admitted that he still doesn’t know what Snowden took with him and wouldn’t have known about the leak at all had Snowden not gone public. He has no idea who else might have stolen secrets before Snowden, or who such insiders might have provided them to. Alexander had no contingency plans in place to deal with this sort of security breach, and even now—four months after Snowden fled the country—still has no coherent response to all this.

For an organization that prides itself on secrecy and security, this is what failure looks like. It is a testament to Alexander’s power that he still has a job.

The second school of thought is that it’s the administration’s fault—not just the present one, but the most recent several. According to this theory, the NSA is simply doing its job. If there’s a problem with the NSA’s actions, it’s because the rules it’s operating under are bad. Like the military, the NSA is merely an instrument of national policy. Blaming the NSA for creating a surveillance state is comparable to blaming the US military for the conduct of the Iraq war. Alexander is performing the mission given to him as best he can, under the rules he has been given, with the sort of zeal you’d expect from someone promoted into that position. And the NSA’s power predated his directorship.

Former NSA Director Michael Hayden exemplifies this in a quote from late July: “Give me the box you will allow me to operate in. I’m going to play to the very edges of that box.”

This doesn’t necessarily mean the administration is deliberately giving the NSA too big a box. More likely, it’s simply that the laws aren’t keeping pace with technology. Every year, technology gives us possibilities that our laws simply don’t cover clearly. And whenever there’s a gray area, the NSA interprets whatever law there is to give them the most expansive authority. They simply run rings around the secret court that rules on these things. My guess is that while they have clearly broken the spirit of the law, it’ll be harder to demonstrate that they broke the letter of the law.

In football terms, the first school of thought says the NSA is out of bounds. The second says the field is too big. I believe that both perspectives have some truth to them, and that the real problem comes from their combination.

Regardless of how we got here, the NSA can’t reform itself. Change cannot come from within; it has to come from above. It’s the job of government: of Congress, of the courts, and of the president. These are the people who have the ability to investigate how things became so bad, rein in the rogue agency, and establish new systems of transparency, oversight, and accountability.

Any solution we devise will make the NSA less efficient at its eavesdropping job. That’s a trade-off we should be willing to make, just as we accept reduced police efficiency caused by requiring warrants for searches and warning suspects that they have the right to an attorney before answering police questions. We do this because we realize that a too-powerful police force is itself a danger, and we need to balance our need for public safety with our aversion of a police state.

The same reasoning needs to apply to the NSA. We want it to eavesdrop on our enemies, but it needs to do so in a way that doesn’t trample on the constitutional rights of Americans, or fundamentally jeopardize their privacy or security. This means that sometimes the NSA won’t get to eavesdrop, just as the protections we put in place to restrain police sometimes result in a criminal getting away. This is a trade-off we need to make willingly and openly, because overall we are safer that way.

Once we do this, there needs to be a cultural change within the NSA. Like at the FBI and CIA after past abuses, the NSA needs new leadership committed to changing its culture. And giving up power.

Our society can handle the occasional terrorist act; we’re resilient, and—if we decided to act that way—indomitable. But a government agency that is above the law… it’s hard to see how America and its freedoms can survive that.

This essay previously appeared on TheAtlantic.com, with the unfortunate title of “Zero Sum: Americans Must Sacrifice Some Security to Reform the NSA.” After I complained, they changed the title to “The NSA-Reform Paradox: Stop Domestic Spying, Get More Security.”

Posted on September 16, 2013 at 6:55 AM • View Comments

Take Back the Internet

Government and industry have betrayed the Internet, and us.

By subverting the Internet at every level to make it a vast, multi-layered and robust surveillance platform, the NSA has undermined a fundamental social contract. The companies that build and manage our Internet infrastructure, the companies that create and sell us our hardware and software, or the companies that host our data: we can no longer trust them to be ethical Internet stewards.

This is not the Internet the world needs, or the Internet its creators envisioned. We need to take it back.

And by we, I mean the engineering community.

Yes, this is primarily a political problem, a policy matter that requires political intervention.

But this is also an engineering problem, and there are several things engineers can—and should—do.

One, we should expose. If you do not have a security clearance, and if you have not received a National Security Letter, you are not bound by a federal confidentially requirements or a gag order. If you have been contacted by the NSA to subvert a product or protocol, you need to come forward with your story. Your employer obligations don’t cover illegal or unethical activity. If you work with classified data and are truly brave, expose what you know. We need whistleblowers.

We need to know how exactly how the NSA and other agencies are subverting routers, switches, the Internet backbone, encryption technologies and cloud systems. I already have five stories from people like you, and I’ve just started collecting. I want 50. There’s safety in numbers, and this form of civil disobedience is the moral thing to do.

Two, we can design. We need to figure out how to re-engineer the Internet to prevent this kind of wholesale spying. We need new techniques to prevent communications intermediaries from leaking private information.

We can make surveillance expensive again. In particular, we need open protocols, open implementations, open systems—these will be harder for the NSA to subvert.

The Internet Engineering Task Force, the group that defines the standards that make the internet run, has a meeting planned for early November in Vancouver. This group needs to dedicate its next meeting to this task. This is an emergency, and demands an emergency response.

Three, we can influence governance. I have resisted saying this up to now, and I am saddened to say it, but the US has proved to be an unethical steward of the Internet. The UK is no better. The NSA’s actions are legitimizing the internet abuses by China, Russia, Iran and others. We need to figure out new means of internet governance, ones that makes it harder for powerful tech countries to monitor everything. For example, we need to demand transparency, oversight, and accountability from our governments and corporations.

Unfortunately, this is going play directly into the hands of totalitarian governments that want to control their country’s Internet for even more extreme forms of surveillance. We need to figure out how to prevent that, too. We need to avoid the mistakes of the International Telecommunications Union, which has become a forum to legitimize bad government behavior, and create truly international governance that can’t be dominated or abused by any one country.

Generations from now, when people look back on these early decades of the Internet, I hope they will not be disappointed in us. We can ensure that they don’t only if each of us makes this a priority, and engages in the debate. We have a moral duty to do this, and we have no time to lose.

Dismantling the surveillance state won’t be easy. Has any country that engaged in mass surveillance of its own citizens voluntarily given up that capability? Has any mass surveillance country avoided becoming totalitarian? Whatever happens, we’re going to be breaking new ground.

Again, the politics of this is a bigger task than the engineering, but the engineering is critical. We need to demand that real technologists be involved in any key government decision making on these issues. We’ve had enough of lawyers and politicians not fully understanding technology; we need technologists at the table when we build tech policy.

To the engineers, I say this: we built the Internet, and some of us have helped to subvert it. Now, those of us who love liberty have to fix it.

This essay previously appeared in the Guardian.

EDITED TO ADD: Slashdot thread. An opposing view to my call to action. And I agree with this, even though the author presents this as an opposing view to mine.

EDITED TO ADD: This essay has been translated into German.

Posted on September 15, 2013 at 11:53 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.