Pierluigi Paganini August 09, 2019

The 3Fun dating mobile app for “curious couples & singles” exposed the location of its members and their personal details.

What do you think about the privacy of dating apps? Well, users of 3Fun, a mobile app for arranging threesomes had an ugly surprise, their data were leaked online.

3Fun claims to have over 1.5 million members worldwide. that exchange more than 180,000 messages every day.

Researchers from Pen Test Partners discovered several severe issues in the dating app, it was exposing the near real-time location of users along with other sensitive data. Exposed data included dates of birth, sexual preferences, chat information, and private pictures. The worst news is that the data are leaked even if the user has correctly enabled privacy settings.

Experts noticed that the filters for data managed by the app were implemented only on the client-side, it was simple for them to capture the requests and remove any restriction.

Below an example of a GET request used 3Fun to send data to the users’ mobile app:

GET /match_users?from=0&latitude=xxxxxx&longitude=+yyyyyy&match_gender=63&match_max_age=61&match_min_age=30&offset=40&search_distance=100 HTTP/1.1

“BUT, that data is only filtered in the mobile app itself, not on the server. It’s just hidden in the mobile app interface if the privacy flag is set. The filtering is client-side, so the API can still be queried for the position data. FFS!” reads the analysis published by Pen Test Partners.

Experts were able to locate users located worldwide, including at the home of the prime minister, Number 10, Downing Street, and in Washington DC, at the White House. 

Experts explained that anyway, the above locations could be the result of GPS coordinates spoofing made by some experts for fun, anyway the lack of security and privacy found in 3Fun app is disconcerting.

Ill-intentioned people could use users’ locations and their private data to stalk 3Fun users or threaten them to publicly reveal their identity. 

Experts also discovered that private photos of the members were accessible to everyone because their URIs were exposed in API response. 

The experts reported their findings to the development team of 3Fun on July 1, 2019, below the reply:

“Dear Alex, Thanks for your kindly reminding. We will fix the problems as soon as possible. Do you have any suggestion? Regards, The 3Fun Team.”

The good news is that 3fun quickly resolved the issues:

“The trilateration and user exposure issues with Grindr and other apps are bad. This is a whole lot worse,” the researchers added. “It’s easy to track users in near real-time, uncovering very personal information and photos.” concludes the post.

Pierluigi Paganini

(SecurityAffairs – dating app, hacking)

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