Entries Tagged "academic papers"

Page 54 of 88

Fingerprinting Computers By Making Them Draw Images

Here’s a new way to identify individual computers over the Internet. The page instructs the browser to draw an image. Because each computer draws the image slightly differently, this can be used to uniquely identify each computer. This is a big deal, because there’s no way to block this right now.

Article. Hacker News thread.

EDITED TO ADD (7/22): This technique was first described in 2012. And it seems that NoScript blocks this. Privacy Badger probably blocks it, too.

EDITED TO ADD (7/23): EFF has a good post on who is using this tracking system—the White House is—and how to defend against it.

And a good story on BoingBoing.

Posted on July 21, 2014 at 3:34 PM • View Comments

How Traffic Shaping Can Help the NSA Evade Legal Oversight

New research paper on how the NSA can evade legal prohibitions against collecting Internet data and metadata on Americans by forcing domestic traffic to leave and return to the US. The general technique is called “traffic shaping,” and has legitimate uses in network management.

From a news article:

The Obama administration previously said there had been Congressional and Judicial oversight of these surveillance laws—notably Section 215 of the Patriot Act, which authorized the collection of Americans’ phone records; and Section 702 of the Foreign Intelligence Surveillance Act (FISA), which authorized the controversial PRISM program to access non-U.S. residents’ emails, social networking, and cloud-stored data.

But the researchers behind this new study say that the lesser-known Executive Order (EO) 12333, which remains solely the domain of the Executive Branch—along with United States Signals Intelligence Directive (USSID) 18, designed to regulate the collection of American’s data from surveillance conducted on foreign soil—can be used as a legal basis for vast and near-unrestricted domestic surveillance on Americans.

The legal provisions offered under EO 12333, which the researchers say “explicitly allows for intentional targeting of U.S. persons” for surveillance purposes when FISA protections do not apply, was the basis of the authority that reportedly allowed the NSA to tap into the fiber cables that connected Google and Yahoo’s overseas to U.S. data centers.

An estimated 180 million user records, regardless of citizenship, were collected from Google and Yahoo data centers each month, according to the leaked documents. The program, known as Operation MUSCULAR, was authorized because the collection was carried out overseas and not on U.S. soil, the researchers say.

The paper also said surveillance can also be carried out across the wider Internet by routing network traffic overseas so it no longer falls within the protection of the Fourth Amendment.

We saw a clumsy example of this in 2013, when a bunch of Internet traffic was mysteriously routed through Iceland. That one was the result of hacking the Border Gateway Protocol (BGP). I assure you that the NSA’s techniques are more effective and less obvious.

EDITED TO ADD (7/13): Author responds to NSA comments.

Posted on July 1, 2014 at 3:23 PM • View Comments

Defending Against Algorithm Substitution Attacks

Interesting paper: M. Bellare, K. Paterson, and P. Rogaway, “Security of Symmetric Encryption against Mass Surveillance.”

Abstract: Motivated by revelations concerning population-wide surveillance of encrypted communications, we formalize and investigate the resistance of symmetric encryption schemes to mass surveillance. The focus is on algorithm-substitution attacks (ASAs), where a subverted encryption algorithm replaces the real one. We assume that the goal of “big-brother” is undetectable subversion, meaning that ciphertexts produced by the subverted encryption algorithm should reveal plaintexts to big-brother yet be indistinguishable to users from those produced by the real encryption scheme. We formalize security notions to capture this goal and then offer both attacks and defenses. In the first category we show that successful (from the point of view of big brother) ASAs may be mounted on a large class of common symmetric encryption schemes. In the second category we show how to design symmetric encryption schemes that avoid such attacks and meet our notion of security. The lesson that emerges is the danger of choice: randomized, stateless schemes are subject to attack while deterministic, stateful ones are not.

Posted on June 24, 2014 at 7:21 AM • View Comments

Paying People to Infect their Computers

Research paper: “It’s All About The Benjamins: An empirical study on incentivizing users to ignore security advice,” by Nicolas Christin, Serge Egelman, Timothy Vidas, and Jens Grossklags.

Abstract: We examine the cost for an attacker to pay users to execute arbitrary code—potentially malware. We asked users at home to download and run an executable we wrote without being told what it did and without any way of knowing it was harmless. Each week, we increased the payment amount. Our goal was to examine whether users would ignore common security advice—not to run untrusted executables­—if there was a direct incentive, and how much this incentive would need to be. We observed that for payments as low as $0.01, 22% of the people who viewed the task ultimately ran our executable. Once increased to $1.00, this proportion increased to 43%. We show that as the price increased, more and more users who understood the risks ultimately ran the code. We conclude that users are generally unopposed to running programs of unknown provenance, so long as their incentives exceed their inconvenience.

The experiment was run on Mechanical Turk, which means we don’t know who these people were or even if they were sitting at computers they owned (as opposed to, say, computers at an Internet cafe somewhere). But if you want to build a fair-trade botnet, this is a reasonable way to go about it.

Two articles.

Posted on June 19, 2014 at 6:28 AM • View Comments

Government Policy on Cell Phone Interception Technology

New paper: “Your Secret Stingray’s No Secret Anymore: The Vanishing Government Monopoly Over Cell Phone Surveillance and its Impact on National Security and Consumer Privacy,” by Christopher Soghoian and Stephanie K. Pell:

Abstract: In the early 1990s, off-the-shelf radio scanners allowed any snoop or criminal to eavesdrop on the calls of nearby cell phone users. These radio scanners could intercept calls due to a significant security vulnerability inherent in then widely used analog cellular phone networks: calls were not encrypted as they traveled over the air. In response to this problem, Congress, rather than exploring options for improving the security of cellular networks, merely outlawed the sale of new radio scanners capable of intercepting cellular signals, which did nothing to prevent the potential use of millions of existing interception-capable radio scanners. Now, nearly two decades after Congress passed legislation intended to protect analog phones from interception by radio scanners, we are rapidly approaching a future with a widespread interception threat to cellular communications very reminiscent of the one scanner posed in the 1990s, but with a much larger range of public and private actors with access to a much more powerful cellular interception technology that exploits security vulnerabilities in our digital cellular networks.

This Article illustrates how cellular interception capabilities and technology have become, for better or worse, globalized and democratized, placing Americans’ cellular communications at risk of interception from foreign governments, criminals, the tabloid press and virtually anyone else with sufficient motive to capture cellular content in transmission. Notwithstanding this risk, US government agencies continue to treat practically everything about this cellular interception technology, as a closely guarded, necessarily secret “source and method,” shrouding the technical capabilities and limitations of the equipment from public discussion, even keeping its very name from public disclosure. This “source and method” argument, although questionable in its efficacy, is invoked to protect law enforcement agencies’ own use of this technology while allegedly preventing criminal suspects from learning how to evade surveillance.

This Article argues that current policy makers should not follow the worn path of attempting to outlaw technology while ignoring, and thus perpetuating, the significant vulnerabilities in cellular communications networks on which it depends. Moreover, lawmakers must resist the reflexive temptation to elevate the sustainability of a particular surveillance technology over the need to curtail the general threat that technology poses to the security of cellular networks. Instead, with regard to this destabilizing, unmediated technology and its increasing general availability at decreasing prices, Congress and appropriate regulators should address these network vulnerabilities directly and thoroughly as part of the larger cyber security policy debates and solutions now under consideration. This Article concludes by offering the beginnings of a way forward for legislators to address digital cellular network vulnerabilities with a new sense of urgency appropriate to the current communications security environment.

Posted on May 21, 2014 at 9:51 AM • View Comments

Preplay Attack on Chip and PIN

Interesting research paper on a bank card chip-and-PIN vulnerability. From the blog post:

Our new paper shows that it is possible to create clone chip cards which normal bank procedures will not be able to distinguish from the real card.

When a Chip and PIN transaction is performed, the terminal requests that the card produces an authentication code for the transaction. Part of this transaction is a number that is supposed to be random, so as to stop an authentication code being generated in advance. However, there are two ways in which the protection can be bypassed: the first requires that the Chip and PIN terminal has a poorly designed random generation (which we have observed in the wild); the second requires that the Chip and PIN terminal or its communications back to the bank can be tampered with (which again, we have observed in the wild).

Posted on May 20, 2014 at 2:01 PM • View Comments

Forged SSL Certificates Pervasive on the Internet

About 0.2% of all SSL certificates are forged. This is the first time I’ve ever seen a number based on real data. News article:

Of 3.45 million real-world connections made to Facebook servers using the transport layer security (TLS) or secure sockets layer protocols, 6,845, or about 0.2 percent of them, were established using forged certificates.

Actual paper.

EDITED TO ADD (6/13): I’m mis-characterizing the study. The study really says that 0.2% of HTTPS traffic to Facebook is intercepted and re-signed, and the vast majority of that interception and resigning happens either on the user’s local computer (by way of trusted security software which is acting scanning proxy) or locally on a private network behind a corporation’s intercepting proxy/firewall. Only a small percentage of intercepted traffic is a result of malware or other nefarious activity.

Posted on May 16, 2014 at 6:43 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.