Entries Tagged "cell phones"

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iPhone Sensor Surveillance

The new iPhone has a motion sensor chip, and that opens up new opportunities for surveillance:

The M7 coprocessors introduce functionality that some may instinctively identify as “creepy.” Even Apple’s own description hints at eerie omniscience: “M7 knows when you’re walking, running, or even driving…” While it’s quietly implemented within iOS, it’s not secret for third party apps (which require an opt-in through pop-up notification, and management through the phone’s Privacy settings). But as we know, most users blindly accept these permissions.

It all comes down to a question of agency in tracking our physical bodies.

The fact that my Fitbit tracks activity without matching it up with all my other data sources, like GPS location or my calendar, is comforting. These data silos can sometimes be frustrating when I want to query across my QS datasets, but the built-in divisions between data about my body ­—and data about the rest of my digital life—leave room for my intentional inquiry and interpretation.

Posted on October 16, 2013 at 7:33 AM • View Comments

New Secure Smart Phone App

It’s hard not to poke fun at this press release for Safeslinger, a new cell phone security app from Carnegie Mellon.

“SafeSlinger provides you with the confidence that the person you are communicating with is actually the person they have represented themselves to be,” said Michael W. Farb, a research programmer at Carnegie Mellon CyLab. “The most important feature is that SafeSlinger provides secure messaging and file transfer without trusting the phone company or any device other than my own smartphone.”

Oddly, Farb believes that he can trust his smart phone.

This headline claims that “even [the] NSA can’t crack” it, but it’s unclear where that claim came from.

Still, it’s good to have encrypted chat programs. This one joins Cryptocat, Silent Circle, and my favorite: OTR.

Posted on October 15, 2013 at 12:37 PM • View Comments

Fingerprinting Burner Phones

In one of the documents recently released by the NSA as a result of an EFF lawsuit, there’s discussion of a specific capability of a call records database to identify disposable “burner” phones.

Let’s consider, then, the very specific data this query tool was designed to return: The times and dates of the first and last call events, but apparently not the times and dates of calls between those endpoints. In other words, this tool is supporting analytic software that only cares when a phone went online, and when it stopped being used. It also gets the total number of calls, and the ratio of unique contacts to calls, but not the specific numbers contacted. Why, exactly, would this limited set of information be useful? And why, in particular, might you want to compare that information across a large number of phones there’s not yet any particular reason to suspect?

One possibility that jumps out at me—and perhaps anyone else who’s a fan of The Wire—is that this is the kind of information you would want if you were trying to identify disposable prepaid “burner” phones being used by a target who routinely cycles through cell phones as a countersurveillance tactic. The number of unique contacts and call/contact ratio would act as a kind of rough fingerprint—you’d assume a phone being used for dedicated clandestine purposes to be fairly consistent on that score—while the first/last call dates help build a timeline: You’re looking for a series of phones that are used for a standard amount of time, and then go dead just as the next phone goes online.

Consider this another illustration of the value of metadata.

Posted on October 14, 2013 at 6:37 AM • View Comments

Apple's iPhone Fingerprint Reader Successfully Hacked

Nice hack from the Chaos Computer Club:

The method follows the steps outlined in this how-to with materials that can be found in almost every household: First, the fingerprint of the enrolled user is photographed with 2400 dpi resolution. The resulting image is then cleaned up, inverted and laser printed with 1200 dpi onto transparent sheet with a thick toner setting. Finally, pink latex milk or white woodglue is smeared into the pattern created by the toner onto the transparent sheet. After it cures, the thin latex sheet is lifted from the sheet, breathed on to make it a tiny bit moist and then placed onto the sensor to unlock the phone. This process has been used with minor refinements and variations against the vast majority of fingerprint sensors on the market.

I’m not surprised. In my essay on Apple’s technology, I wrote: “I’m sure that someone with a good enough copy of your fingerprint and some rudimentary materials engineering capability—or maybe just a good enough printer—can authenticate his way into your iPhone.”

I don’t agree with CCC’s conclusion, though:

“We hope that this finally puts to rest the illusions people have about fingerprint biometrics. It is plain stupid to use something that you can´t change and that you leave everywhere every day as a security token”, said Frank Rieger, spokesperson of the CCC. “The public should no longer be fooled by the biometrics industry with false security claims. Biometrics is fundamentally a technology designed for oppression and control, not for securing everyday device access.”

Apple is trying to balance security with convenience. This is a cell phone, not a ICBM launcher or even a bank account withdrawal device. Apple is offering an option to replace a four-digit PIN—something that a lot of iPhone users don’t even bother with—with a fingerprint. Despite its drawbacks, I think it’s a good trade-off for a lot of people.

EDITED TO ADD (10/13): The print for the CCC hack was lifted from the iPhone.

Posted on September 24, 2013 at 9:20 AM • View Comments

Google Knows Every Wi-Fi Password in the World

This article points out that as people are logging into Wi-Fi networks from their Android phones, and backing up those passwords along with everything else into Google’s cloud, that Google is amassing an enormous database of the world’s Wi-Fi passwords. And while it’s not every Wi-Fi password in the world, it’s almost certainly a large percentage of them.

Leaving aside Google’s intentions regarding this database, it is certainly something that the US government could force Google to turn over with a National Security Letter.

Something else to think about.

Posted on September 20, 2013 at 7:05 AM • View Comments

iPhone Fingerprint Authentication

When Apple bought AuthenTec for its biometrics technology—reported as one of its most expensive purchases—there was a lot of speculation about how the company would incorporate biometrics in its product line. Many speculate that the new Apple iPhone to be announced tomorrow will come with a fingerprint authentication system, and there are several ways it could work, such as swiping your finger over a slit-sized reader to have the phone recognize you.

Apple would be smart to add biometric technology to the iPhone. Fingerprint authentication is a good balance between convenience and security for a mobile device.

Biometric systems are seductive, but the reality isn’t that simple. They have complicated security properties. For example, they are not keys. Your fingerprint isn’t a secret; you leave it everywhere you touch.

And fingerprint readers have a long history of vulnerabilities as well. Some are better than others. The simplest ones just check the ridges of a finger; some of those can be fooled with a good photocopy. Others check for pores as well. The better ones verify pulse, or finger temperature. Fooling them with rubber fingers is harder, but often possible. A Japanese researcher had good luck doing this over a decade ago with the gelatin mixture that’s used to make Gummi bears.

The best system I’ve ever seen was at the entry gates of a secure government facility. Maybe you could have fooled it with a fake finger, but a Marine guard with a big gun was making sure you didn’t get the opportunity to try. Disney World uses a similar system at its park gates—but without the Marine guards.

A biometric system that authenticates you and you alone is easier to design than a biometric system that is supposed to identify unknown people. That is, the question “Is this the finger belonging to the owner of this iPhone?” is a much easier question for the system to answer than “Whose finger is this?”

There are two ways an authentication system can fail. It can mistakenly allow an unauthorized person access, or it can mistakenly deny access to an authorized person. In any consumer system, the second failure is far worse than the first. Yes, it can be problematic if an iPhone fingerprint system occasionally allows someone else access to your phone. But it’s much worse if you can’t reliably access your own phone—you’d junk the system after a week.

If it’s true that Apple’s new iPhone will have biometric security, the designers have presumably erred on the side of ensuring that the user can always get in. Failures will be more common in cold weather, when your shriveled fingers just got out of the shower, and so on. But there will certainly still be the traditional PIN system to fall back on.

So…can biometric authentication be hacked?

Almost certainly. I’m sure that someone with a good enough copy of your fingerprint and some rudimentary materials engineering capability—or maybe just a good enough printer—can authenticate his way into your iPhone. But, honestly, if some bad guy has your iPhone and your fingerprint, you’ve probably got bigger problems to worry about.

The final problem with biometric systems is the database. If the system is centralized, there will be a large database of biometric information that’s vulnerable to hacking. A system by Apple will almost certainly be local—you authenticate yourself to the phone, not to any network—so there’s no requirement for a centralized fingerprint database.

Apple’s move is likely to bring fingerprint readers into the mainstream. But all applications are not equal. It’s fine if your fingers unlock your phone. It’s a different matter entirely if your fingerprint is used to authenticate your iCloud account. The centralized database required for that application would create an enormous security risk.

This essay previously appeared on Wired.com.

EDITED TO ADD: The new iPhone does have a fingerprint reader.

Posted on September 11, 2013 at 6:43 AM • View Comments

Circumventing Communications Blackouts

Rangzen looks like a really interesting ad hoc mesh networking system to circumvent government-imposed communications blackouts. I am particularly interested in how it uses reputation to determine who can be trusted, while maintaining some level of anonymity.

Academic paper:

Abstract: A challenging problem in dissent networking is that of circumventing large-scale communication blackouts imposed by oppressive governments. Although prior work has not focused on the need for user anonymity, we contend that it is essential. Without anonymity, governments can use communication networks to track and persecute users. A key challenge for decentralized networks is that of resource allocation and control. Network resources must be shared in a manner that deprioritizes unwanted traffic and abusive users. This task is typically addressed through reputation systems that conflict with anonymity. Our work addresses this paradox: We prioritize resources in a privacy-preserving manner to create an attack-resilient, anonymity-preserving, mobile ad-hoc network. Our prioritization mechanism exploits the properties of a social trust graph to promote messages relayed via trusted nodes. We present Rangzen, a microblogging solution that uses smartphones to opportunistically relay messages among citizens in a delay-tolerant network (DTN) that is independent of government or corporate-controlled infrastructure.

This is exactly the sort of thing I was thinking about in this essay.

Posted on August 14, 2013 at 7:43 AM • View Comments

Twitter's Two-Factor Authentication System

Twitter just rolled out a pretty nice two-factor authentication system using your smart phone as the second factor:

The new two-factor system works like this. A user enrolls using the mobile app, which generates a 2048-bit RSA keypair. The private key lives on the phone itself, and the public key is uploaded to Twitter’s server.

When Twitter receives a new login request with a username and password, the server sends a challenge based on a 190-bit, 32 character random nonce, to the mobile app—along with a notification that gives the user the time, location, and browser information associated with the login request. The user can then opt to approve or deny this login request. If approved, the app replies to a challenge with its private key, relays that information back to the server. The server compares that challenge with a request ID, and if it authenticates, the user is automatically logged in.

On the user end, this means there’s no string of numbers to enter, nor do you have to swap to a third party authentication app or carrier. You just use the Twitter client itself. It means that the system isn’t vulnerable to a compromised SMS delivery channel, and moreover, it’s easy.

Posted on August 8, 2013 at 12:20 PM • View Comments

How Apple Continues to Make Security Invisible

Interesting article:

Apple is famously focused on design and human experience as their top guiding principles. When it comes to security, that focus created a conundrum. Security is all about placing obstacles in the way of attackers, but (despite the claims of security vendors) those same obstacles can get in the way of users, too.

[…]

For many years, Apple tended to choose good user experience at the expense of leaving users vulnerable to security risks. That strategy worked for a long time, in part because Apple’s comparatively low market share made its products less attractive targets. But as Apple products began to gain in popularity, many of us in the security business wondered how Apple would adjust its security strategies to its new position in the spotlight.

As it turns out, the company not only handled that change smoothly, it has embraced it. Despite a rocky start, Apple now applies its impressive design sensibilities to security, playing the game its own way and in the process changing our expectations for security and technology.

EDITED TO ADD (7/11): iOS security white paper.

Posted on July 5, 2013 at 1:33 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.