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Can The NSA Really Track Turned-Off Cellphones?

It depends on semantics, security experts say. What's clear is that surveillance is becoming much more sophisticated.

Mathew J. Schwartz

July 24, 2013

6 Min Read

Surveillance alert: For almost a decade, the National Security Agency has had the ability to track cell phones, even when they're turned off.

But it all depends on what's meant by "track," "phone" and "off."

This tracking ability was revealed on July 20 by The Washington Post, in an article chronicling the evolution of the NSA's signals intelligence work in the wake of the Sept. 11 attacks, when intelligence agencies, the military and the FBI created an "insatiable demand for its work product." That demand was driven in no small part by CIA and paramilitary units and clandestine Joint Special Operations Command (JSOC) teams who wanted to use cellphones as real-time beacons to track (and eventually capture or kill) al-Qaeda leaders.

One of the "products" supposedly on offer from September 2004 was "a new NSA technique that enabled the agency to find cellphones even when they were turned off," reported the Post. "JSOC troops called this 'The Find,' and it gave them thousands of new targets, including members of a burgeoning al-Qaeda-sponsored insurgency in Iraq, according to members of the unit."

That news was reported verbatim by numerous media outlets, including Russia Today, which noted that "12 years after the Sept. 11 attack -- and more than three since al-Qaeda leader Osama bin Laden was executed thanks to tactics employed by the NSA, CIA and others -- these operations have not been scaled back." In other words, adding to the list of programs that are collecting data on Americans, now we have to worry about our location being tracked by cellphones even when they're turned off.

But security experts chimed in that cellphones really can't be tracked when they're turned off. "This isn't true -- at least, it's not what you think," said Robert David Graham, CEO of Errata Security, in a blog post. "If you turn your iPhone/Android off, the NSA cannot track you by your phone number" or any other identifying information broadcast by the phone, he said.

Now come the caveats. For one thing, phones that are turned off may not actually be turned off. "If the NSA elects to modify your phone's firmware, removing the battery is the only way to ensure it's actually 'off,'" tweeted Marsh Ray, who works on Windows Azure active authentication at Microsoft.

Or for more proactive surveillance, someone could plant a bug on a phone. "The best way to track an 'off' phone is to -- secretly -- install a chip, connected to the phone's battery supply," Graham said. "Thus, even when the phone is 'off,' that added chip would still be 'on.' In this case, it's not really the phone itself that's being tracked, but that chip. As long as you had a battery, the same tracking technique would work for portable laptops, your shoe or even a gun." The Federal Bureau of Alcohol, Tobacco, and Firearms (ATF) attempted to use this technique as part of its Operation Fast and Furious gun-tracking program, "but the batteries drained too fast," Graham said. Obviously, secreting a chip on a phone, which needs to be regularly recharged by its user, would help avoid that type of problem.

But old phones may not actually turn off, even if they appear to be powered down. For example, Graham said many old "feature phones," even when they were switched off, would have a baseband processor power up every 10 minutes or so to retrieve SMS messages, but not phone calls. "The moral of this is that just because you define the phone as 'off' doesn't mean that it's 100% completely 'off' all the time," he said.

An intelligence agency that could exploit this technological caveat, of course, would be able to track targets without their knowledge, as the Post story makes clear. And thus an entire intelligence ecosystem grew up around related data-collection practices, fed in part by the NSA embedding so-called "tactical cryptologic support teams" within military units and tasking them with collecting data during missions.

Another program, dubbed the Geolocation Cell, or Geo Cell, involved a combined team from the NSA and the National Geospatial-Intelligence Agency. Its purpose was to track targets in real time -- motto: "We Track 'Em, You Whack 'Em" -- so they could be killed using drones.

Grisly stuff, but what about for the rest of us -- meaning, anyone who's not an Iraqi insurgent or suspected terrorist? Numerous NSA surveillance programs have recently come to light thanks to the leaks by former agency contractor Edward Snowden, a Booz Allen Hamilton employee who worked at an agency facility in Hawaii that processes intelligence from around the Pacific Rim. Some of the thousands of documents he removed reveal a panoply of obscurely named, and overlapping, surveillance programs with names such as PRISM (audio, email and video interception), Mainway (traffic analysis of cell phone calls), Marina (Internet traffic analysis) and Nucleon (telephone content interception). Do you now have to worry about the NSA being able to track you even when the cell phone in your pocket has supposedly been powered down?

Predictably, White House and intelligence officials argue that the NSA's surveillance programs are both lawful and designed to avoid collecting data on U.S. residents. Civil liberties advocates, however, have criticized the agency's approach of collecting all possible data, then using search algorithms to attempt to avoid retrieving information about Americans.

But the scale of the data collection and potential for abuse should give us pause. Furthermore, if the NSA can apply its advanced skills to intercept this type of data, it could presage more mundane efforts by companies to track consumers. To wit, the Economist recently reported that Nordstrom was testing a Wi-Fi tracking system from Euclid Analytics, designed to track shoppers who enter or pass by 17 of their stores. The system works by passively watching for smartphones' and laptops' Wi-Fi beacons, thus tracking people without their devices even logging into a store-controlled Wi-Fi network.

Nordstrom posted a public notice near its stores saying that people might be tracked via their smartphones. But should such practices be allowed -- warning or no? And how far of a step is it for retailers to amass data not just about consumers via Wi-Fi, but also about their digital wallets? Tracking people via their smartphones is no less ominous when it's being practiced by a retailer instead of the NSA.

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About the Author(s)

Mathew J. Schwartz


Mathew Schwartz served as the InformationWeek information security reporter from 2010 until mid-2014.

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