{"id":127753,"date":"2014-07-03T15:38:42","date_gmt":"2014-07-03T15:38:42","guid":{"rendered":"http:\/\/rinf.com\/alt-news\/?p=127753"},"modified":"2014-07-03T18:21:55","modified_gmt":"2014-07-03T18:21:55","slug":"android-device-telling-world-youve","status":"publish","type":"post","link":"http:\/\/rinf.com\/alt-news\/latest-news\/android-device-telling-world-youve\/","title":{"rendered":"Is Your Android Device Telling the World Where You’ve Been?"},"content":{"rendered":"
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PETER ECKERSLEY\u00a0AND\u00a0<\/span>JEREMY GILLULA<\/em><\/p>\n

Do you own an Android device? Is it less than three years old? If so, then when your phone\u2019s screen is off and it\u2019s not connected to a Wi-Fi network, there’s a high risk that it is broadcasting your location history to anyone within Wi-Fi range that wants to listen.<\/p>\n

This location history comes in the form of the names of wireless networks your phone has previously connected to. These frequently identify places you’ve been, including homes (\u201cTom\u2019s Wi-Fi\u201d), workplaces (\u201cCompany XYZ office net\u201d), churches and political offices (\u201cCounty Party HQ\u201d), small businesses (\u201cToulouse Lautrec’s house of ill-repute\u201d), and travel destinations (\u201cTehran Airport wifi\u201d). This data is arguably more dangerous than that leaked in\u00a0previous location data scandals<\/a>\u00a0because it clearly denotes in human language places that you’ve spent enough time to use the Wi-Fi. Normally eavesdroppers would need to spend some effort extracting this sort of information from the latititude\/longitude history typically discussed in location privacy analysis. But even when networks seem less identifiable, there are ways to\u00a0look them up<\/a>.<\/p>\n

We briefly mentioned this problem during our recent post about Apple deciding to\u00a0randomize MAC addresses in iOS 8<\/a>. As we pointed out there, Wi-Fi devices that are not actively connected to a network can send out messages that contain the names of networks they\u2019ve joined in the past in an effort to speed up the connection process.

2<\/a><\/p>\n

In Android we traced this behavior to a feature introduced in Honeycomb (Android 3.1<\/span>) called Preferred Network Offload (PNO).\u00a0<\/span>3<\/a>\u00a0PNO is supposed to allow phones and tablets to establish and maintain Wi-Fi connections even when they\u2019re in low-power mode (i.e. when the screen is turned off). The goal is to extend battery life and reduce mobile data usage, since Wi-Fi uses less power than cellular data. But for some reason, even though none of the Android phones we tested broadcast the names of networks they knew about when their screens were on, many\u00a0of the phones running Honeycomb or later (and even one running Gingerbread) broadcast the names of networks they knew about when their screens were turned off.4<\/a><\/span><\/p>\n

Response from Google<\/h3>\n

When we brought this issue to Google\u2019s attention, they responded that:<\/p>\n

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“We take the security of our users’ location data very seriously and we’re always happy to be made aware of potential issues ahead of time. Since changes to this behavior would potentially affect user connectivity to hidden access points, we are still investigating what changes are appropriate for a future release.”<\/p>\n<\/blockquote>\n

Additionally, yesterday a Google employee submitted a patch to wpa_supplicant which fixes this issue. While we are glad this problem is being addressed so quickly, it will still be some time before that fix gets integrated into the downstream Android code. And even then, Android fragmentation and the\u00a0broken update process<\/a>\u00a0for non-Google Android devices could delay or even prevent many users from receiving the fix. (We hope\u00a0Google can make progress on this problem<\/a>, too.)<\/p>\n

Protective Steps You Can Take Today<\/h3>\n

With that said, a workaround is available (for most devices) for users who want to protect their privacy right now: go into your phone\u2019s \u201cAdvanced Wi-Fi\u201d settings and set the \u201cKeep Wi-Fi on during sleep\u201d option to \u201cNever\u201d. Unfortunately this will cause a moderate increase in data usage and power consumption\u2013something users shouldn\u2019t have to do in order to keep their phone from telling everyone everywhere they\u2019ve been.<\/p>\n

Unfortunately, on at least one device we tested\u2014a Motorola Droid 4 running Android 4.1.2\u2014even this wasn\u2019t sufficient. On the Droid 4, and perhaps on other phones, the only practical way to prevent the phone from leaking location is to manually forget the networks you don’t want broadcast, or disable Wi-Fi entirely whenever you aren’t actively connecting to a known Wi-Fi network.5<\/a>\u00a0You can also find apps that will do this automatically for you.<\/p>\n

Location history is extremely sensitive information. We urge Google to ship their fix as soon as possible, and other Android distributors to offer prompt updates containing it.<\/p>\n