Entries Tagged "privacy"

Page 92 of 144

Man-in-the-Middle Attacks Against SSL

Says Matt Blaze:

A decade ago, I observed that commercial certificate authorities protect you from anyone from whom they are unwilling to take money. That turns out to be wrong; they don’t even do that much.

Scary research by Christopher Soghoian and Sid Stamm:

Abstract: This paper introduces a new attack, the compelled certificate creation attack, in which government agencies compel a certificate authority to issue false SSL certificates that are then used by intelligence agencies to covertly intercept and hijack individuals’ secure Web-based communications. We reveal alarming evidence that suggests that this attack is in active use. Finally, we introduce a lightweight browser add-on that detects and thwarts such attacks.

Even more scary, Soghoian and Stamm found that hardware to perform this attack is being produced and sold:

At a recent wiretapping convention, however, security researcher Chris Soghoian discovered that a small company was marketing internet spying boxes to the feds. The boxes were designed to intercept those communications—without breaking the encryption—by using forged security certificates, instead of the real ones that websites use to verify secure connections. To use the appliance, the government would need to acquire a forged certificate from any one of more than 100 trusted Certificate Authorities.

[…]

The company in question is known as Packet Forensics…. According to the flyer: “Users have the ability to import a copy of any legitimate key they obtain (potentially by court order) or they can generate ‘look-alike’ keys designed to give the subject a false sense of confidence in its authenticity.” The product is recommended to government investigators, saying “IP communication dictates the need to examine encrypted traffic at will.” And, “Your investigative staff will collect its best evidence while users are lulled into a false sense of security afforded by web, e-mail or VOIP encryption.”

Matt Blaze has the best analysis. Read his whole commentary; this is just the ending:

It’s worth pointing out that, from the perspective of a law enforcement or intelligence agency, this sort of surveillance is far from ideal. A central requirement for most government wiretapping (mandated, for example, in the CALEA standards for telephone interception) is that surveillance be undetectable. But issuing a bogus web certificate carries with it the risk of detection by the target, either in real-time or after the fact, especially if it’s for a web site already visited. Although current browsers don’t ordinarily detect unusual or suspiciously changed certificates, there’s no fundamental reason they couldn’t (and the Soghoian/Stamm paper proposes a Firefox plugin to do just that). In any case, there’s no reliable way for the wiretapper to know in advance whether the target will be alerted by a browser that scrutinizes new certificates.

Also, it’s not clear how web interception would be particularly useful for many of the most common law enforcement investigative scenarios. If a suspect is buying books or making hotel reservations online, it’s usually a simple (and legally relatively uncomplicated) matter to just ask the vendor about the transaction, no wiretapping required. This suggests that these products may be aimed less at law enforcement than at national intelligence agencies, who might be reluctant (or unable) to obtain overt cooperation from web site operators (who may be located abroad).

Posted on April 12, 2010 at 1:32 PMView Comments

Schneier on "Security, Privacy, and the Generation Gap"

Last month at the RSA Conference, I gave a talk titled “Security, Privacy, and the Generation Gap.” It was pretty good, but it was the first time I gave that talk in front of a large audience—and its newness showed.

Last week, I gave the same talk again, at the CACR Higher Education Security Summit at Indiana University. It was much, much better the second time around, and there’s a video available.

Posted on April 9, 2010 at 12:55 PMView Comments

Privacy and Control

In January Facebook Chief Executive, Mark Zuckerberg, declared the age of privacy to be over. A month earlier, Google Chief Eric Schmidt expressed a similar sentiment. Add Scott McNealy’s and Larry Ellison’s comments from a few years earlier, and you’ve got a whole lot of tech CEOs proclaiming the death of privacy—especially when it comes to young people.

It’s just not true. People, including the younger generation, still care about privacy. Yes, they’re far more public on the Internet than their parents: writing personal details on Facebook, posting embarrassing photos on Flickr and having intimate conversations on Twitter. But they take steps to protect their privacy and vociferously complain when they feel it violated. They’re not technically sophisticated about privacy and make mistakes all the time, but that’s mostly the fault of companies and Web sites that try to manipulate them for financial gain.

To the older generation, privacy is about secrecy. And, as the Supreme Court said, once something is no longer secret, it’s no longer private. But that’s not how privacy works, and it’s not how the younger generation thinks about it. Privacy is about control. When your health records are sold to a pharmaceutical company without your permission; when a social-networking site changes your privacy settings to make what used to be visible only to your friends visible to everyone; when the NSA eavesdrops on everyone’s e-mail conversations—your loss of control over that information is the issue. We may not mind sharing our personal lives and thoughts, but we want to control how, where and with whom. A privacy failure is a control failure.

People’s relationship with privacy is socially complicated. Salience matters: People are more likely to protect their privacy if they’re thinking about it, and less likely to if they’re thinking about something else. Social-networking sites know this, constantly reminding people about how much fun it is to share photos and comments and conversations while downplaying the privacy risks. Some sites go even further, deliberately hiding information about how little control—and privacy—users have over their data. We all give up our privacy when we’re not thinking about it.

Group behavior matters; we’re more likely to expose personal information when our peers are doing it. We object more to losing privacy than we value its return once it’s gone. Even if we don’t have control over our data, an illusion of control reassures us. And we are poor judges of risk. All sorts of academic research backs up these findings.

Here’s the problem: The very companies whose CEOs eulogize privacy make their money by controlling vast amounts of their users’ information. Whether through targeted advertising, cross-selling or simply convincing their users to spend more time on their site and sign up their friends, more information shared in more ways, more publicly means more profits. This means these companies are motivated to continually ratchet down the privacy of their services, while at the same time pronouncing privacy erosions as inevitable and giving users the illusion of control.

You can see these forces in play with Google‘s launch of Buzz. Buzz is a Twitter-like chatting service, and when Google launched it in February, the defaults were set so people would follow the people they corresponded with frequently in Gmail, with the list publicly available. Yes, users could change these options, but—and Google knew this—changing options is hard and most people accept the defaults, especially when they’re trying out something new. People were upset that their previously private e-mail contacts list was suddenly public. A Federal Trade Commission commissioner even threatened penalties. And though Google changed its defaults, resentment remained.

Facebook tried a similar control grab when it changed people’s default privacy settings last December to make them more public. While users could, in theory, keep their previous settings, it took an effort. Many people just wanted to chat with their friends and clicked through the new defaults without realizing it.

Facebook has a history of this sort of thing. In 2006 it introduced News Feeds, which changed the way people viewed information about their friends. There was no true privacy change in that users could not see more information than before; the change was in control—or arguably, just in the illusion of control. Still, there was a large uproar. And Facebook is doing it again; last month, the company announced new privacy changes that will make it easier for it to collect location data on users and sell that data to third parties.

With all this privacy erosion, those CEOs may actually be right—but only because they’re working to kill privacy. On the Internet, our privacy options are limited to the options those companies give us and how easy they are to find. We have Gmail and Facebook accounts because that’s where we socialize these days, and it’s hard—especially for the younger generation—to opt out. As long as privacy isn’t salient, and as long as these companies are allowed to forcibly change social norms by limiting options, people will increasingly get used to less and less privacy. There’s no malice on anyone’s part here; it’s just market forces in action. If we believe privacy is a social good, something necessary for democracy, liberty and human dignity, then we can’t rely on market forces to maintain it. Broad legislation protecting personal privacy by giving people control over their personal data is the only solution.

This essay originally appeared on Forbes.com.

EDITED TO ADD (4/13): Google responds. And another essay on the topic.

Posted on April 6, 2010 at 7:47 AMView Comments

Security Cameras in the New York City Subways

The New York Times has an article about cameras in the subways. The article is all about how horrible it is that the cameras don’t work:

Moreover, nearly half of the subway system’s 4,313 security cameras that have been installed—in stations and tunnels throughout the system—do not work, because of either shoddy software or construction problems, say officials with the Metropolitan Transportation Authority, which operates the city’s bus, subway and train system.

I certainly agree that taxpayers should be upset when something they’ve purchased doesn’t function as expected. But way down at the bottom of the article, we find:

Even without the cameras, officials said crime in the transit system had dropped to a record low. In 1990, the system averaged 47.8 crimes a day, compared with 5.3 so far this year. “The subway system is safer than it’s ever been,” said Kevin Ortiz, an authority spokesman.

No data on how many crimes were solved by cameras, but we know from other studies that their effect on crime is minimal.

Posted on March 31, 2010 at 1:24 PMView Comments

Side-Channel Attacks on Encrypted Web Traffic

Nice paper: “Side-Channel Leaks in Web Applications: a Reality Today, a Challenge Tomorrow,” by Shuo Chen, Rui Wang, XiaoFeng Wang, and Kehuan Zhang.

Abstract. With software-as-a-service becoming mainstream, more and more applications are delivered to the client through the Web. Unlike a desktop application, a web application is split into browser-side and server-side components. A subset of the application’s internal information flows are inevitably exposed on the network. We show that despite encryption, such a side-channel information leak is a realistic and serious threat to user privacy. Specifically, we found that surprisingly detailed sensitive information is being leaked out from a number of high-profile, top-of-the-line web applications in healthcare, taxation, investment and web search: an eavesdropper can infer the illnesses/medications/surgeries of the user, her family income and investment secrets, despite HTTPS protection; a stranger on the street can glean enterprise employees’ web search queries, despite WPA/WPA2 Wi-Fi encryption. More importantly, the root causes of the problem are some fundamental characteristics of web applications: stateful communication, low entropy input for better interaction, and significant traffic distinctions. As a result, the scope of the problem seems industry-wide. We further present a concrete analysis to demonstrate the challenges of mitigating such a threat, which points to the necessity of a disciplined engineering practice for side-channel mitigations in future web application developments.

We already know that eavesdropping on an SSL-encrypted web session can leak a lot of information about the person’s browsing habits. Since the size of both the page requests and the page downloads are different, an eavesdropper can sometimes infer which links the person clicked on and what pages he’s viewing.

This paper extends that work. Ed Felten explains:

The new paper shows that this inference-from-size problem gets much, much worse when pages are using the now-standard AJAX programming methods, in which a web “page” is really a computer program that makes frequent requests to the server for information. With more requests to the server, there are many more opportunities for an eavesdropper to make inferences about what you’re doing—to the point that common applications leak a great deal of private information.

Consider a search engine that autocompletes search queries: when you start to type a query, the search engine gives you a list of suggested queries that start with whatever characters you have typed so far. When you type the first letter of your search query, the search engine page will send that character to the server, and the server will send back a list of suggested completions. Unfortunately, the size of that suggested completion list will depend on which character you typed, so an eavesdropper can use the size of the encrypted response to deduce which letter you typed. When you type the second letter of your query, another request will go to the server, and another encrypted reply will come back, which will again have a distinctive size, allowing the eavesdropper (who already knows the first character you typed) to deduce the second character; and so on. In the end the eavesdropper will know exactly which search query you typed. This attack worked against the Google, Yahoo, and Microsoft Bing search engines.

Many web apps that handle sensitive information seem to be susceptible to similar attacks. The researchers studied a major online tax preparation site (which they don’t name) and found that it leaks a fairly accurate estimate of your Adjusted Gross Income (AGI). This happens because the exact set of questions you have to answer, and the exact data tables used in tax preparation, will vary based on your AGI. To give one example, there is a particular interaction relating to a possible student loan interest calculation, that only happens if your AGI is between $115,000 and $145,000—so that the presence or absence of the distinctively-sized message exchange relating to that calculation tells an eavesdropper whether your AGI is between $115,000 and $145,000. By assembling a set of clues like this, an eavesdropper can get a good fix on your AGI, plus information about your family status, and so on.

For similar reasons, a major online health site leaks information about which medications you are taking, and a major investment site leaks information about your investments.

The paper goes on to talk about mitigation—padding page requests and downloads to a constant size is the obvious one—but they’re difficult and potentially expensive.

More articles.

Posted on March 26, 2010 at 6:04 AMView Comments

Electronic Health Record Security Analysis

In British Columbia:

When Auditor-General John Doyle and his staff investigated the security of electronic record-keeping at the Vancouver Coastal Health Authority, they found trouble everywhere they looked.

“In every key area we examined, we found serious weaknesses,” wrote Doyle. “Security controls throughout the network and over the database were so inadequate that there was a high risk of external and internal attackers being able to access or extract information without the authority even being aware of it.”

[…]

“No intrusion prevention and detection systems exist to prevent or detect certain types of [online] attacks. Open network connections in common business areas. Dial-in remote access servers that bypass security. Open accounts existing, allowing health care data to be copied even outside the Vancouver Coastal Health Care authority at any time.”

More than 4,000 users were found to have access to the records in the database, many of them at a far higher level than necessary.

[…]

“Former client records and irrelevant records for current clients are still accessible to system users. Hundreds of former users, both employees and contractors, still have access to resources through active accounts, network accounts, and virtual private network accounts.”

While this report is from Canada, the same issues apply to any electronic patient record system in the U.S. What I find really interesting is that the Canadian government actually conducted a security analysis of the system, rather than just maintaining that everything would be fine. I wish the U.S. would do something similar.

The report, “The PARIS System for Community Care Services: Access and Security,” is here.

Posted on March 23, 2010 at 12:23 PMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.