Entries Tagged "backdoors"

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More on Backdooring (or Not) WhatsApp

Yesterday, I blogged about a Facebook plan to backdoor WhatsApp by adding client-side scanning and filtering. It seems that I was wrong, and there are no such plans.

The only source for that post was a Forbes essay by Kalev Leetaru, which links to a previous Forbes essay by him, which links to a video presentation from a Facebook developers conference.

Leetaru extrapolated a lot out of very little. I watched the video (the relevant section is at the 23:00 mark), and it doesn’t talk about client-side scanning of messages. It doesn’t talk about messaging apps at all. It discusses using AI techniques to find bad content on Facebook, and the difficulties that arise from dynamic content:

So far, we have been keeping this fight [against bad actors and harmful content] on familiar grounds. And that is, we have been training our AI models on the server and making inferences on the server when all the data are flooding into our data centers.

While this works for most scenarios, it is not the ideal setup for some unique integrity challenges. URL masking is one such problem which is very hard to do. We have the traditional way of server-side inference. What is URL masking? Let us imagine that a user sees a link on the app and decides to click on it. When they click on it, Facebook actually logs the URL to crawl it at a later date. But…the publisher can dynamically change the content of the webpage to make it look more legitimate [to Facebook]. But then our users click on the same link, they see something completely different — oftentimes it is disturbing; oftentimes it violates our policy standards. Of course, this creates a bad experience for our community that we would like to avoid. This and similar integrity problems are best solved with AI on the device.

That might be true, but it also would hand whatever secret-AI sauce Facebook has to every one of its users to reverse engineer — which means it’s probably not going to happen. And it is a dumb idea, for reasons Steve Bellovin has pointed out.

Facebook’s first published response was a comment on the Hacker News website from a user named “wcathcart,” which Cardozo assures me is Will Cathcart, the vice president of WhatsApp. (I have no reason to doubt his identity, but surely there is a more official news channel that Facebook could have chosen to use if they wanted to.) Cathcart wrote:

We haven’t added a backdoor to WhatsApp. The Forbes contributor referred to a technical talk about client side AI in general to conclude that we might do client side scanning of content on WhatsApp for anti-abuse purposes.

To be crystal clear, we have not done this, have zero plans to do so, and if we ever did it would be quite obvious and detectable that we had done it. We understand the serious concerns this type of approach would raise which is why we are opposed to it.

Facebook’s second published response was a comment on my original blog post, which has been confirmed to me by the WhatsApp people as authentic. It’s more of the same.

So, this was a false alarm. And, to be fair, Alec Muffet called foul on the first Forbes piece:

So, here’s my pre-emptive finger wag: Civil Society’s pack mentality can make us our own worst enemies. If we go around repeating one man’s Germanic conspiracy theory, we may doom ourselves to precisely what we fear. Instead, we should ­ we must ­ take steps to constructively demand what we actually want: End to End Encryption which is worthy of the name.

Blame accepted. But in general, this is the sort of thing we need to watch for. End-to-end encryption only secures data in transit. The data has to be in the clear on the device where it is created, and it has to be in the clear on the device where it is consumed. Those are the obvious places for an eavesdropper to get a copy.

This has been a long process. Facebook desperately wanted to convince me to correct the record, while at the same time not wanting to write something on their own letterhead (just a couple of comments, so far). I spoke at length with Privacy Policy Manager Nate Cardozo, whom Facebook hired last December from EFF. (Back then, I remember thinking of him — and the two other new privacy hires — as basically human warrant canaries. If they ever leave Facebook under non-obvious circumstances, we know that things are bad.) He basically leveraged his historical reputation to assure me that WhatsApp, and Facebook in general, would never do something like this. I am trusting him, while also reminding everyone that Facebook has broken so many privacy promises that they really can’t be trusted.

Final note: If they want to be trusted, Adam Shostack and I gave them a road map.

Hacker News thread.

EDITED TO ADD (8/4): Slashdot covered my retraction.

Posted on August 2, 2019 at 2:18 PMView Comments

Facebook Plans on Backdooring WhatsApp

This article points out that Facebook’s planned content moderation scheme will result in an encryption backdoor into WhatsApp:

In Facebook’s vision, the actual end-to-end encryption client itself such as WhatsApp will include embedded content moderation and blacklist filtering algorithms. These algorithms will be continually updated from a central cloud service, but will run locally on the user’s device, scanning each cleartext message before it is sent and each encrypted message after it is decrypted.

The company even noted that when it detects violations it will need to quietly stream a copy of the formerly encrypted content back to its central servers to analyze further, even if the user objects, acting as true wiretapping service.

Facebook’s model entirely bypasses the encryption debate by globalizing the current practice of compromising devices by building those encryption bypasses directly into the communications clients themselves and deploying what amounts to machine-based wiretaps to billions of users at once.

Once this is in place, it’s easy for the government to demand that Facebook add another filter — one that searches for communications that they care about — and alert them when it gets triggered.

Of course alternatives like Signal will exist for those who don’t want to be subject to Facebook’s content moderation, but what happens when this filtering technology is built into operating systems?

The problem is that if Facebook’s model succeeds, it will only be a matter of time before device manufacturers and mobile operating system developers embed similar tools directly into devices themselves, making them impossible to escape. Embedding content scanning tools directly into phones would make it possible to scan all apps, including ones like Signal, effectively ending the era of encrypted communications.

I don’t think this will happen — why does AT&T care about content moderation — but it is something to watch?

EDITED TO ADD (8/2): This story is wrong. Read my correction.

Posted on August 1, 2019 at 6:51 AMView Comments

Attorney General William Barr on Encryption Policy

Yesterday, Attorney General William Barr gave a major speech on encryption policy — what is commonly known as “going dark.” Speaking at Fordham University in New York, he admitted that adding backdoors decreases security but that it is worth it.

Some hold this view dogmatically, claiming that it is technologically impossible to provide lawful access without weakening security against unlawful access. But, in the world of cybersecurity, we do not deal in absolute guarantees but in relative risks. All systems fall short of optimality and have some residual risk of vulnerability a point which the tech community acknowledges when they propose that law enforcement can satisfy its requirements by exploiting vulnerabilities in their products. The real question is whether the residual risk of vulnerability resulting from incorporating a lawful access mechanism is materially greater than those already in the unmodified product. The Department does not believe this can be demonstrated.

Moreover, even if there was, in theory, a slight risk differential, its significance should not be judged solely by the extent to which it falls short of theoretical optimality. Particularly with respect to encryption marketed to consumers, the significance of the risk should be assessed based on its practical effect on consumer cybersecurity, as well as its relation to the net risks that offering the product poses for society. After all, we are not talking about protecting the Nation’s nuclear launch codes. Nor are we necessarily talking about the customized encryption used by large business enterprises to protect their operations. We are talking about consumer products and services such as messaging, smart phones, e-mail, and voice and data applications. If one already has an effective level of security say, by way of illustration, one that protects against 99 percent of foreseeable threats is it reasonable to incur massive further costs to move slightly closer to optimality and attain a 99.5 percent level of protection? A company would not make that expenditure; nor should society. Here, some argue that, to achieve at best a slight incremental improvement in security, it is worth imposing a massive cost on society in the form of degraded safety. This is untenable. If the choice is between a world where we can achieve a 99 percent assurance against cyber threats to consumers, while still providing law enforcement 80 percent of the access it might seek; or a world, on the other hand, where we have boosted our cybersecurity to 99.5 percent but at a cost reducing law enforcements [sic] access to zero percent the choice for society is clear.

I think this is a major change in government position. Previously, the FBI, the Justice Department and so on had claimed that backdoors for law enforcement could be added without any loss of security. They maintained that technologists just need to figure out how: ­an approach we have derisively named “nerd harder.”

With this change, we can finally have a sensible policy conversation. Yes, adding a backdoor increases our collective security because it allows law enforcement to eavesdrop on the bad guys. But adding that backdoor also decreases our collective security because the bad guys can eavesdrop on everyone. This is exactly the policy debate we should be having­ — not the fake one about whether or not we can have both security and surveillance.

Barr makes the point that this is about “consumer cybersecurity,” and not “nuclear launch codes.” This is true, but ignores the huge amount of national security-related communications between those two poles. The same consumer communications and computing devices are used by our lawmakers, CEOs, legislators, law enforcement officers, nuclear power plant operators, election officials and so on. There’s no longer a difference between consumer tech and government tech — it’s all the same tech.

Barr also says:

Further, the burden is not as onerous as some make it out to be. I served for many years as the general counsel of a large telecommunications concern. During my tenure, we dealt with these issues and lived through the passage and implementation of CALEA the Communications Assistance for Law Enforcement Act. CALEA imposes a statutory duty on telecommunications carriers to maintain the capability to provide lawful access to communications over their facilities. Companies bear the cost of compliance but have some flexibility in how they achieve it, and the system has by and large worked. I therefore reserve a heavy dose of skepticism for those who claim that maintaining a mechanism for lawful access would impose an unreasonable burden on tech firms especially the big ones. It is absurd to think that we would preserve lawful access by mandating that physical telecommunications facilities be accessible to law enforcement for the purpose of obtaining content, while allowing tech providers to block law enforcement from obtaining that very content.

That telecommunications company was GTE­which became Verizon. Barr conveniently ignores that CALEA-enabled phone switches were used to spy on government officials in Greece in 2003 — which seems to have been an NSA operation — and on a variety of people in Italy in 2006. Moreover, in 2012 every CALEA-enabled switch sold to the Defense Department had security vulnerabilities. (I wrote about all this, and more, in 2013.)

The final thing I noticed about the speech is that is it not about iPhones and data at rest. It is about communications: ­data in transit. The “going dark” debate has bounced back and forth between those two aspects for decades. It seems to be bouncing once again.

I hope that Barr’s latest speech signals that we can finally move on from the fake security vs. privacy debate, and to the real security vs. security debate. I know where I stand on that: As computers continue to permeate every aspect of our lives, society, and critical infrastructure, it is much more important to ensure that they are secure from everybody — even at the cost of law-enforcement access — than it is to allow access at the cost of security. Barr is wrong, it kind of is like these systems are protecting nuclear launch codes.

This essay previously appeared on Lawfare.com.

EDITED TO ADD: More news articles.

EDITED TO ADD (7/28): Gen. Hayden comments.

EDITED TO ADD (7/30): Good response by Robert Graham.

Posted on July 24, 2019 at 6:43 AMView Comments

Backdoor Built into Android Firmware

In 2017, some Android phones came with a backdoor pre-installed:

Criminals in 2017 managed to get an advanced backdoor preinstalled on Android devices before they left the factories of manufacturers, Google researchers confirmed on Thursday.

Triada first came to light in 2016 in articles published by Kaspersky here and here, the first of which said the malware was “one of the most advanced mobile Trojans” the security firm’s analysts had ever encountered. Once installed, Triada’s chief purpose was to install apps that could be used to send spam and display ads. It employed an impressive kit of tools, including rooting exploits that bypassed security protections built into Android and the means to modify the Android OS’ all-powerful Zygote process. That meant the malware could directly tamper with every installed app. Triada also connected to no fewer than 17 command and control servers.

In July 2017, security firm Dr. Web reported that its researchers had found Triada built into the firmware of several Android devices, including the Leagoo M5 Plus, Leagoo M8, Nomu S10, and Nomu S20. The attackers used the backdoor to surreptitiously download and install modules. Because the backdoor was embedded into one of the OS libraries and located in the system section, it couldn’t be deleted using standard methods, the report said.

On Thursday, Google confirmed the Dr. Web report, although it stopped short of naming the manufacturers. Thursday’s report also said the supply chain attack was pulled off by one or more partners the manufacturers used in preparing the final firmware image used in the affected devices.

This is a supply chain attack. It seems to be the work of criminals, but it could just as easily have been a nation-state.

Posted on June 21, 2019 at 11:42 AMView Comments

Cybersecurity for the Public Interest

The Crypto Wars have been waging off-and-on for a quarter-century. On one side is law enforcement, which wants to be able to break encryption, to access devices and communications of terrorists and criminals. On the other are almost every cryptographer and computer security expert, repeatedly explaining that there’s no way to provide this capability without also weakening the security of every user of those devices and communications systems.

It’s an impassioned debate, acrimonious at times, but there are real technologies that can be brought to bear on the problem: key-escrow technologies, code obfuscation technologies, and backdoors with different properties. Pervasive surveillance capitalism­ — as practiced by the Internet companies that are already spying on everyone — ­matters. So does society’s underlying security needs. There is a security benefit to giving access to law enforcement, even though it would inevitably and invariably also give that access to others. However, there is also a security benefit of having these systems protected from all attackers, including law enforcement. These benefits are mutually exclusive. Which is more important, and to what degree?

The problem is that almost no policymakers are discussing this policy issue from a technologically informed perspective, and very few technologists truly understand the policy contours of the debate. The result is both sides consistently talking past each other, and policy proposals­ — that occasionally become law­ — that are technological disasters.

This isn’t sustainable, either for this issue or any of the other policy issues surrounding Internet security. We need policymakers who understand technology, but we also need cybersecurity technologists who understand — ­and are involved in — ­policy. We need public-interest technologists.

Let’s pause at that term. The Ford Foundation defines public-interest technologists as “technology practitioners who focus on social justice, the common good, and/or the public interest.” A group of academics recently wrote that public-interest technologists are people who “study the application of technology expertise to advance the public interest, generate public benefits, or promote the public good.” Tim Berners-Lee has called them “philosophical engineers.” I think of public-interest technologists as people who combine their technological expertise with a public-interest focus: by working on tech policy, by working on a tech project with a public benefit, or by working as a traditional technologist for an organization with a public benefit. Maybe it’s not the best term­ — and I know not everyone likes it­ — but it’s a decent umbrella term that can encompass all these roles.

We need public-interest technologists in policy discussions. We need them on congressional staff, in federal agencies, at non-governmental organizations (NGOs), in academia, inside companies, and as part of the press. In our field, we need them to get involved in not only the Crypto Wars, but everywhere cybersecurity and policy touch each other: the vulnerability equities debate, election security, cryptocurrency policy, Internet of Things safety and security, big data, algorithmic fairness, adversarial machine learning, critical infrastructure, and national security. When you broaden the definition of Internet security, many additional areas fall within the intersection of cybersecurity and policy. Our particular expertise and way of looking at the world is critical for understanding a great many technological issues, such as net neutrality and the regulation of critical infrastructure. I wouldn’t want to formulate public policy about artificial intelligence and robotics without a security technologist involved.

Public-interest technology isn’t new. Many organizations are working in this area, from older organizations like EFF and EPIC to newer ones like Verified Voting and Access Now. Many academic classes and programs combine technology and public policy. My cybersecurity policy class at the Harvard Kennedy School is just one example. Media startups like The Markup are doing technology-driven journalism. There are even programs and initiatives related to public-interest technology inside for-profit corporations.

This might all seem like a lot, but it’s really not. There aren’t enough people doing it, there aren’t enough people who know it needs to be done, and there aren’t enough places to do it. We need to build a world where there is a viable career path for public-interest technologists.

There are many barriers. There’s a report titled A Pivotal Moment that includes this quote: “While we cite individual instances of visionary leadership and successful deployment of technology skill for the public interest, there was a consensus that a stubborn cycle of inadequate supply, misarticulated demand, and an inefficient marketplace stymie progress.”

That quote speaks to the three places for intervention. One: the supply side. There just isn’t enough talent to meet the eventual demand. This is especially acute in cybersecurity, which has a talent problem across the field. Public-interest technologists are a diverse and multidisciplinary group of people. Their backgrounds come from technology, policy, and law. We also need to foster diversity within public-interest technology; the populations using the technology must be represented in the groups that shape the technology. We need a variety of ways for people to engage in this sphere: ways people can do it on the side, for a couple of years between more traditional technology jobs, or as a full-time rewarding career. We need public-interest technology to be part of every core computer-science curriculum, with “clinics” at universities where students can get a taste of public-interest work. We need technology companies to give people sabbaticals to do this work, and then value what they’ve learned and done.

Two: the demand side. This is our biggest problem right now; not enough organizations understand that they need technologists doing public-interest work. We need jobs to be funded across a wide variety of NGOs. We need staff positions throughout the government: executive, legislative, and judiciary branches. President Obama’s US Digital Service should be expanded and replicated; so should Code for America. We need more press organizations that perform this kind of work.

Three: the marketplace. We need job boards, conferences, and skills exchanges­ — places where people on the supply side can learn about the demand.

Major foundations are starting to provide funding in this space: the Ford and MacArthur Foundations in particular, but others as well.

This problem in our field has an interesting parallel with the field of public-interest law. In the 1960s, there was no such thing as public-interest law. The field was deliberately created, funded by organizations like the Ford Foundation. They financed legal aid clinics at universities, so students could learn housing, discrimination, or immigration law. They funded fellowships at organizations like the ACLU and the NAACP. They created a world where public-interest law is valued, where all the partners at major law firms are expected to have done some public-interest work. Today, when the ACLU advertises for a staff attorney, paying one-third to one-tenth normal salary, it gets hundreds of applicants. Today, 20% of Harvard Law School graduates go into public-interest law, and the school has soul-searching seminars because that percentage is so low. Meanwhile, the percentage of computer-science graduates going into public-interest work is basically zero.

This is bigger than computer security. Technology now permeates society in a way it didn’t just a couple of decades ago, and governments move too slowly to take this into account. That means technologists now are relevant to all sorts of areas that they had no traditional connection to: climate change, food safety, future of work, public health, bioengineering.

More generally, technologists need to understand the policy ramifications of their work. There’s a pervasive myth in Silicon Valley that technology is politically neutral. It’s not, and I hope most people reading this today knows that. We built a world where programmers felt they had an inherent right to code the world as they saw fit. We were allowed to do this because, until recently, it didn’t matter. Now, too many issues are being decided in an unregulated capitalist environment where significant social costs are too often not taken into account.

This is where the core issues of society lie. The defining political question of the 20th century was: “What should be governed by the state, and what should be governed by the market?” This defined the difference between East and West, and the difference between political parties within countries. The defining political question of the first half of the 21st century is: “How much of our lives should be governed by technology, and under what terms?” In the last century, economists drove public policy. In this century, it will be technologists.

The future is coming faster than our current set of policy tools can deal with. The only way to fix this is to develop a new set of policy tools with the help of technologists. We need to be in all aspects of public-interest work, from informing policy to creating tools all building the future. The world needs all of our help.

This essay previously appeared in the January/February 2019 issue of IEEE Security & Privacy. I maintain a public-interest tech resources page here.

Posted on May 3, 2019 at 4:33 AMView Comments

G7 Comes Out in Favor of Encryption Backdoors

From a G7 meeting of interior ministers in Paris this month, an “outcome document“:

Encourage Internet companies to establish lawful access solutions for their products and services, including data that is encrypted, for law enforcement and competent authorities to access digital evidence, when it is removed or hosted on IT servers located abroad or encrypted, without imposing any particular technology and while ensuring that assistance requested from internet companies is underpinned by the rule law and due process protection. Some G7 countries highlight the importance of not prohibiting, limiting, or weakening encryption;

There is a weird belief amongst policy makers that hacking an encryption system’s key management system is fundamentally different than hacking the system’s encryption algorithm. The difference is only technical; the effect is the same. Both are ways of weakening encryption.

Posted on April 23, 2019 at 9:14 AMView Comments

China Spying on Undersea Internet Cables

Supply chain security is an insurmountably hard problem. The recent focus is on Chinese 5G equipment, but the problem is much broader. This opinion piece looks at undersea communications cables:

But now the Chinese conglomerate Huawei Technologies, the leading firm working to deliver 5G telephony networks globally, has gone to sea. Under its Huawei Marine Networks component, it is constructing or improving nearly 100 submarine cables around the world. Last year it completed a cable stretching nearly 4,000 miles from Brazil to Cameroon. (The cable is partly owned by China Unicom, a state-controlled telecom operator.) Rivals claim that Chinese firms are able to lowball the bidding because they receive subsidies from Beijing.

Just as the experts are justifiably concerned about the inclusion of espionage “back doors” in Huawei’s 5G technology, Western intelligence professionals oppose the company’s engagement in the undersea version, which provides a much bigger bang for the buck because so much data rides on so few cables.

This shouldn’t surprise anyone. For years, the US and the Five Eyes have had a monopoly on spying on the Internet around the globe. Other countries want in.

As I have repeatedly said, we need to decide if we are going to build our future Internet systems for security or surveillance. Either everyone gets to spy, or no one gets to spy. And I believe we must choose security over surveillance, and implement a defense-dominant strategy.

Posted on April 15, 2019 at 6:30 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.