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Mischief Managed: The Facebook Privacy Nightmare Caused By One Chrome Extension

Angela Randall 02-06-2015

I solemnly swear that I am up to no good. That about sums things up.


For a short while, a Chrome extension called the Marauder’s Map was letting Facebook users track their friends’ exact locations. Here’s what you need to know about this Facebook privacy Prepare Your Account Privacy For Facebook Graph Search [Weekly Facebook Tips] Every time Facebook releases a new feature to learn more about our friends, many people realise that their privacy settings are not adequate anymore. Their latest new feature, Facebook Graph Search, is no exception -... Read More breach.

The Marauder’s Map

The name comes from Harry Potter, where the Marauder’s Map shows the exact locations of everyone in Hogwarts. In reality, this extension was not far removed from this, in that you could see all of your friends pinpointed on a map, tracked in real time. Scary stuff.

It has been noted that this could track Facebook users’ location coordinates down to 5 decimal places. So, it could tell you where people were down to the meter.

Marauder's Map Facebook Location 2

It’s Been Axed — Sort Of

The official Chrome extension of the Marauder’s Map has recently been removed at Facebook’s request. However, it still exists on GitHub and could easily be recreated by anyone who knows how to code browser extensions for Facebook.


What this means for users is that the privacy issue Smartphone Privacy Settings You Need To Activate Today Smartphones ship with plenty of default settings that could be leaking your info. Let's dive in and tweak them. Read More has temporarily abated, as Facebook has not yet done anything to stop this information being exposed in the first place. It’s still quite easy for similar tools to do the same job: exposing the whereabouts of all of your Facebook friends.

“The latitude and longitude coordinates of the message locations have more than 5 decimal places of precision, making it possible to pinpoint the sender’s location to less than a meter.” — Aran Khanna

It Uses Data From the Facebook Messenger App

The way this extension worked was to get Facebook location data How Bad Are Those Facebook Messenger Permissions Anyway? You've probably been hearing a lot about Facebook's Messenger app. Let's quell the rumors and find out if the permissions are as bad as they claim. Read More from the Facebook messenger app, which tracks users in real time. The user would need to be viewing the Facebook messenger web app for it to work.

Any Facebook user who has opted not to use the Facebook messenger app because of invasive permissions How To Use Facebook On Android Without All The Invasive Permissions Facebook's Android app requires a ton of permissions, and it shouldn't be trusted with them. The Tinfoil app for Facebook is the privacy-conscious solution. Read More , or chosen to opt-out of location sharing would have shared their location information Are You Sharing Your Location On Facebook Without Knowing? [Weekly Facebook Tips] Have you been giving your stalkers your address inadvertently? You might accidentally be giving all of your Facebook friends the exact location of your house, your office and where your kids go to school. Read More less frequently. These people would only be located by check-ins, photo locations Facebook Photo Privacy Settings You Need To Know About As with everything regarding privacy on Facebook, managing your photos' privacy settings isn't always easy. Read More , their home location, and — oh, everything else.

“Creepily track your friends from FB messages” — Marauder’s Map Extension Description

This Is Actually a Big Deal

Now, many of you may be thinking this is no big deal as you’re only showing the information to your friends. This is true to some extent. In fact, there can be good reasons to track loved ones Why Tracking Your Significant Other's Location Isn't Always Evil But is it really so wrong to track your partner's movements, assuming it's consensual? Read More .


But think about how many of your Facebook friends are “close” friends, and how many are work colleagues and acquaintances. And how many of your crazy exes are still friends with good friends of yours? Couldn’t they potentially find out where your friend is and hope to see you there?

They could. And that’s why this extension and its future imitators are a stalker’s dream and a privacy advocate’s nightmare.

Creepily Track Your Friends

Aran Khanna, the student developer of this extension, knows full well how dangerous this could be. It’s actually quite interesting to read his original Medium post about the development of this extension. And although he removed the extension from the Chrome store, it’s really up to Facebook to fix this.

Marauder's Map Facebook Location


“I found that I could infer a schedule for almost everyone in this chat as well as the other active chats I am in.” — Aran Khanna

Facebook says it’s working on a fix, but in the meantime all they can suggest is that you opt out of sending your location information by clicking on the blue arrow in Facebook Messenger.


Do You Share Location Data With Facebook?

If you don’t want to share your location data with Facebook, be sure to disable it in the messenger app on your mobile device. Or, if you’re really concerned, use an alternative Facebook messaging app Don't Want to Use Facebook Messenger? 10 Slick Alternatives to Try Facebook Messenger isn't perfect. Why keep using it? Here are the best alternatives to Facebook Messenger. Read More or even a different messaging app altogether 5 Best Free Messaging Apps for Android Need a free way to send messages to friends and family with your phone for free? Check out these apps. Read More .

As Aran Khanna himself asks, why do so many people give up their location data so readily on Messenger? Do you?


Related topics: Browser Extensions, Facebook, Google Chrome, Online Privacy.

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