Feb 18 2014, 11:33am CST | by Forbes
The wildly popular Tinder app has perfected the art of the frictionless hookup to levels not seen since Erica Jong lost her fear of flying in the ’70s. Part of the appeal is how responsive and location-aware the app is. Olympic athletes in Sochi, whose lives are devoted to speed, are reportedly using the app to spice up their downtime.
Unfortunately, two of the aspects responsible for the high quality of its user experience also potentially put its users at risk for stalking by predators with a modicum of hacking ability. First, the location processing takes place on the client side, so actual location data for matched users in a 25 mile radius is delivered directly to the user’s device, unmediated by the Tinder servers. Second, that data is incredibly accurate, within 100 ft. or less.
In July, a security vulnerability was reported concerning how Tinder was sending latitude and longitude co-ordinates of potential matches directly to iOS client apps. Researchers Erik Cabetas and Max Veytsman from the NYC-based firm Include Security began to investigate. “Anyone with rudimentary programming skills could query the Tinder API directly and pull down the co-ordinates of any user,” they write on the company’s blog. “We found a vulnerability that lets you get exact latitude and longitude co-ordinates for any Tinder user. “
Tinder fixed this issue, but Cabetas and Veytsman discovered that the fix itself created another vulnerability which they then reported to the company. Security companies do this all the time to demonstrate their chops and generate publicity. This case is particularly interesting both because of Tinder’s rapidly growing popularity and because according to Cabetas and Veytsman, “flaws in location information handling have been common place in the mobile app space and continue to remain common if developers don’t handle location information more sensitively.”
For those unfamiliar with the app, Tinder displays a pile of snapshots of potential dates in a user’s immediate area. If both sides of a match express interest, they have the option to message each other directly inside the app. The rest is up to them. What makes Tinder particularly popular is that it works equally well for people who just want the vicarious pleasure of cruising with no real intention of following through as it does for those who really want to hookup in real life.
But what if just creating an account on Tinder and opening the app occasionally is enough to make your location visible to someone you have no intention of ever meeting? This was the possibility raised by this second Tinder vulnerability, and by many location-based apps with oversharing APIs.
The “fixed” version of Tinder replaced the GPS latitude and longitude coordinates with very precise distances (in miles to 15 decimal places, which is literally about five feet!) But knowing how far away you are from a person doesn’t tell you anything about direction, right? It can if you are a little clever and studied trigonometry in High School.
There is a form of triangulation called trilateration that enables you to use geometry to calculate a precise location based on a set of three precise distances. So, if you know that you can query the Tinder API for the precise distance of a user based on their ID, all you need is to create three dummy accounts to acquire the three required distances.
To show how such a process can be automated, Cabetas and Veytsman created a (private) app (for demonstration only) called Tinder Finder (see video below) that coordinates the activities of the dummy accounts and calculates the position of the targeted user. The researchers explain that while their “Proof of concept attack uses Facebook authentication to find the user’s Tinder id, Facebook is NOT needed to exploit this vulnerability, and no action by Facebook could mitigate this vulnerability.”
So what does this mean in practical terms for the users of location-based apps? Most importantly, not to take an app’s word for it that your location data is secure when using it. There is simply not the authentication infrastructure yet in place to assure both the security and ease of use that would make these apps genuinely bullet-proof. Many players are working on this problem, from Apple to Google to the FIDO Alliance, but until there is some clear consensus between hardware and software that users adopt widely, these kind of vulnerabilities will only increase.
For app makers it seems that making user IDs harder to “sniff” and making dummy accounts harder to acquire can make triangulation schemes more difficult. For users, forgoing the ease of Facebook or Google authentication may make sniffing out your user ID more challenging for hackers and being sure to close the app when not in use will cut down on the amount of location data the app has access to in the first place.
None of this, I am sure, will keep people from using Tinder. This is about sex, after all, and risk, for many, is part of the turn on. But it wouldn’t take very many incidents of aggressive unwanted attention linked to such an app to change the whole landscape for location-based services. Fortunately, no such problems have been reported in relation to Tinder.
The good news is that, as of this writing, Include Security tells me that although the window for this exploit was open for a couple of months it seems now that appropriate action has been taken which has rendered the issue “unreproducible.” There are, however, many such apps out there and new ones appearing each day, so we probably have not heard the last of this tricky bit of triangulation.
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Source: Forbes Business
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