Entries Tagged "traffic analysis"

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More on NSA Data Collection

There’s an article from Wednesday’s Wall Street Journal that gives more details about the NSA’s data collection efforts.

The system has the capacity to reach roughly 75% of all U.S. Internet traffic in the hunt for foreign intelligence, including a wide array of communications by foreigners and Americans. In some cases, it retains the written content of emails sent between citizens within the U.S. and also filters domestic phone calls made with Internet technology, these people say.


The programs, code-named Blarney, Fairview, Oakstar, Lithium and Stormbrew, among others, filter and gather information at major telecommunications companies. Blarney, for instance, was established with AT&T Inc….

This filtering takes place at more than a dozen locations at major Internet junctions in the U.S., officials say. Previously, any NSA filtering of this kind was largely believed to be happening near points where undersea or other foreign cables enter the country.


The systems operate like this: The NSA asks telecom companies to send it various streams of Internet traffic it believes most likely to contain foreign intelligence. This is the first cut of the data. These requests don’t ask for all Internet traffic. Rather, they focus on certain areas of interest, according to a person familiar with the legal process. “It’s still a large amount of data, but not everything in the world,” this person says.

The second cut is done by NSA. It briefly copies the traffic and decides which communications to keep based on what it calls “strong selectors”—say, an email address, or a large block of computer addresses that correspond to an organization it is interested in. In making these decisions, the NSA can look at content of communications as well as information about who is sending the data. One U.S. official says the agency doesn’t itself “access” all the traffic within the surveillance system. The agency defines access as “things we actually touch,” this person says, pointing out that the telecom companies do the first stage of filtering.

The surveillance system is built on relationships with telecommunications carriers that together cover about 75% of U.S. Internet communications. They must hand over what the NSA asks for under orders from the secret Foreign Intelligence Surveillance Court. The firms search Internet traffic based on the NSA’s criteria, current and former officials say.

The NSA seems to have finally found a PR agency with a TS/SI clearance, since there was a response to this story. They’ve also had a conference call with the press, and the Director of National Intelligence is on Twitter and Tumblr.

I am completely croggled by the fact that the NSA apparently had absolutely no contingency plans for this sort of thing.

Posted on August 27, 2013 at 1:19 PMView Comments

Mail Cover

From a FOIAed Department of Transportation document on investigative techniques:

A “mail cover” is the process by which the U.S. Postal Service records any data appearing on the outside cover of any class of mail, sealed or unsealed, or by which a record is made of the contents of unsealed (second-, third-, or fourth-class) mail matter as allowed by law. This “rnail cover” is done to obtain information in the interest of protecting national security, locating a fugitive, or obtaining evidence of commission or attempted commission of a felony crime, or assist in the identification of property, proceeds, or assets forfeitable under law.

Seems to be the paper mail equivalent of a pen register. I’d never heard of the term before.

EDITED TO ADD (5/11): Here is a 2002 NPR interview on mail cover, based on these two articles.

Posted on May 10, 2013 at 6:47 AMView Comments

19th-Century Traffic Analysis

There’s a nice example of traffic analysis in the book No Name, by Wilkie Collins (1862). The attacker, Captain Wragge, needs to know whether a letter has been placed in the mail. He knows who it will have been addressed to if it has been mailed, and with that information, is able to convince the postmaster to tell him that it has, in fact, been mailed:

If she had gone to the admiral’s, no choice would be left him but to follow the coach, to catch the train by which she traveled, and to outstrip her afterward on the drive from the station in Essex to St. Crux. If, on the contrary, she had been contented with writing to her master, it would only be necessary to devise measures for intercepting the letter. The captain decided on going to the post-office, in the first place. Assuming that the housekeeper had written, she would not have left the letter at the mercy of the servant—she would have seen it safely in the letter-box before leaving Aldborough.

“Good-morning,” said the captain, cheerfully addressing the postmaster. “I am Mr. Bygrave of North Shingles. I think you have a letter in the box, addressed to Mr.—?”

The postmaster was a short man, and consequently a man with a proper idea of his own importance. He solemnly checked Captain Wragge in full career.

“When a letter is once posted, sir,” he said, “nobody out of the office has any business with it until it reaches its address.”

The captain was not a man to be daunted, even by a postmaster. A bright idea struck him. He took out his pocketbook, in which Admiral Bartram’s address was written, and returned to the charge.

“Suppose a letter has been wrongly directed by mistake?” he began. “And suppose the writer wants to correct the error after the letter is put into the box?”

“When a letter is once posted, sir,” reiterated the impenetrable local authority, “nobody out of the office touches it on any pretense whatever.”

“Granted, with all my heart,” persisted the captain. “I don’t want to touch it—I only want to explain myself. A lady has posted a letter here, addressed to ‘Noel Vanstone, Esq., Admiral Bartram’s, St. Crux-in-the-Marsh, Essex.’ She wrote in a great hurry, and she is not quite certain whether she added the name of the post-town, ‘Ossory.’ It is of the last importance that the delivery of the letter should not be delayed. What is to hinder your facilitating the post-office work, and obliging a lady, by adding the name of the post-town (if it happens to be left out), with your own hand? I put it to you as a zealous officer, what possible objection can there be to granting my request?”

The postmaster was compelled to acknowledge that there could be no objection, provided nothing but a necessary line was added to the address, provided nobody touched the letter but himself, and provided the precious time of the post-office was not suffered to run to waste. As there happened to be nothing particular to do at that moment, he would readily oblige the lady at Mr. Bygrave’s request.

Captain Wragge watched the postmaster’s hands, as they sorted the letters in the box, with breathless eagerness. Was the letter there? Would the hands of the zealous public servant suddenly stop? Yes! They stopped, and picked out a letter from the rest.

“‘Noel Vanstone, Esquire,’ did you say?” asked the postmaster, keeping the letter in his own hand.

“‘Noel Vanstone, Esquire,'” replied the captain, “‘Admiral Bartram’s, St. Crux-in-the-Marsh.'”

“Ossory, Essex,” chimed in the postmaster, throwing the letter back into the box. “The lady has made no mistake, sir. The address is quite right.”

Nothing but a timely consideration of the heavy debt he owed to appearances prevented Captain Wragge from throwing his tall white hat up in the air as soon as he found the street once more. All further doubt was now at an end. Mrs. Lecount had written to her master—therefore Mrs. Lecount was on her way to Zurich!

Posted on February 19, 2013 at 12:52 PMView Comments

Eavesdropping on Smart Homes with Distributed Wireless Sensors

Protecting your daily in-home activity information from a wireless snooping attack,” by Vijay Srinivasan, John Stankovic, and Kamin Whitehouse:

Abstract: In this paper, we first present a new privacy leak in residential wireless ubiquitous computing systems, and then we propose guidelines for designing future systems to prevent this problem. We show that we can observe private activities in the home such as cooking, showering, toileting, and sleeping by eavesdropping on the wireless transmissions of sensors in a home, even when all of the transmissions are encrypted. We call this the Fingerprint and Timing-based Snooping (FATS) attack. This attack can already be carried out on millions of homes today, and may become more important as ubiquitous computing environments such as smart homes and assisted living facilities become more prevalent. In this paper, we demonstrate and evaluate the FATS attack on eight different homes containing wireless sensors. We also propose and evaluate a set of privacy preserving design guidelines for future wireless ubiquitous systems and show how these guidelines can be used in a hybrid fashion to prevent against the FATS attack with low implementation costs.

The group was able to infer surprisingly detailed activity information about the residents, including when they were home or away, when they were awake or sleeping, and when they were performing activities such as showering or cooking. They were able to infer all this without any knowledge of the location, semantics, or source identifier of the wireless sensors, while assuming perfect encryption of the data and source identifiers.

Posted on August 31, 2010 at 12:39 PMView Comments

P2P Privacy

Interesting research:

The team of researchers, which includes graduate students David Choffnes (electrical engineering and computer science) and Dean Malmgren (chemical and biological engineering), and postdoctoral fellow Jordi Duch (chemical and biological engineering), studied connection patterns in the BitTorrent file-sharing network — one of the largest and most popular P2P systems today. They found that over the course of weeks, groups of users formed communities where each member consistently connected with other community members more than with users outside the community.

“This was particularly surprising because BitTorrent is designed to establish connections at random, so there is no a priori reason for such strong communities to exist,” Bustamante says. After identifying this community behavior, the researchers showed that an eavesdropper could classify users into specific communities using a relatively small number of observation points. Indeed, a savvy attacker can correctly extract communities more than 85 percent of the time by observing only 0.01 percent of the total users. Worse yet, this information could be used to launch a “guilt-by-association” attack, where an attacker need only determine the downloading behavior of one user in the community to convincingly argue that all users in the communities are doing the same.

Given the impact of this threat, the researchers developed a technique that prevents accurate classification by intelligently hiding user-intended downloading behavior in a cloud of random downloading. They showed that this approach causes an eavesdropper’s classification to be wrong the majority of the time, providing users with grounds to claim “plausible deniability” if accused.

Posted on April 9, 2009 at 7:07 AMView Comments

NSA Snooping on Cell Phone Calls

From CNet:

A recent article in the London Review of Books revealed that a number of private companies now sell off-the-shelf data-mining solutions to government spies interested in analyzing mobile-phone calling records and real-time location information. These companies include ThorpeGlen, VASTech, Kommlabs, and Aqsacom–all of which sell “passive probing” data-mining services to governments around the world.

ThorpeGlen, a U.K.-based firm, offers intelligence analysts a graphical interface to the company’s mobile-phone location and call-record data-mining software. Want to determine a suspect’s “community of interest“? Easy. Want to learn if a single person is swapping SIM cards or throwing away phones (yet still hanging out in the same physical location)? No problem.

In a Web demo (PDF) (mirrored here) to potential customers back in May, ThorpeGlen’s vice president of global sales showed off the company’s tools by mining a dataset of a single week’s worth of call data from 50 million users in Indonesia, which it has crunched in order to try and discover small anti-social groups that only call each other.

Posted on September 17, 2008 at 12:49 PMView Comments

Programming for Wholesale Surveillance and Data Mining

AT&T has done the research:

They use high-tech data-mining algorithms to scan through the huge daily logs of every call made on the AT&T network; then they use sophisticated algorithms to analyze the connections between phone numbers: who is talking to whom? The paper literally uses the term “Guilt by Association” to describe what they’re looking for: what phone numbers are in contact with other numbers that are in contact with the bad guys?

When this research was done, back in the last century, the bad guys where people who wanted to rip off AT&T by making fraudulent credit-card calls. (Remember, back in the last century, intercontinental long-distance voice communication actually cost money!) But it’s easy to see how the FBI could use this to chase down anyone who talked to anyone who talked to a terrorist. Or even to a “terrorist.”

Posted on October 31, 2007 at 12:03 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.