Nearly a billion users of a dozen chat apps for Android including popular apps such as Instagram, Oovoo, OKCupid and Grindr could be at risk from eavesdroppers and snoopers after University of New Haven researchers found serious data leakage problems.

With many of the most popular chat apps on Android affected, tech news site CNET calculates that nearly a billion (968 million) users could be putting highly private data in the hands of apps that transmit and store it unencrypted.

Many of the Android apps (the researchers focused on Android rather than iOS, although there is no evidence the iOS apps behave differently), send text wirelessly unencrypted, and store images on servers for weeks without encryption or authentication.

Chat apps leak: 12 Android apps leak text and images

According to CNET’s report, the following apps sent text, images, location maps and video unencrypted - Instagram, OKCupid, OoVoo, Tango, Kik, Nimbuzz, MeetMe, MessageMe, TextMe, Grindr, HeyWire, Hike and TextPlus.

The site notes that not every app sent every form of media unencrypted, but said that all sent at least some forms, from pictures to text in unencrypted forms.

Others stored media such as images on servers unencrypted and without any form of authentication “for weeks”.

'Sniffer' software reveals leaks

The researchers used PC ‘sniffer’ software such as Wireshark and Network Miner to monitor the data transmitted by the apps, and found images and text transmitted and stored unencrypted - and potentially at risk from snoopers.

In the series of YouTube videos, one researcher says, “We recorded network traffic in Wireshark, to see if files remained on the server. For Instagram, we found an image stored in their servers, unencrypted and without authentication.”

“Next, we opened up Oovoo and sent the keyword “Sparklehorse,” and it was picked up in Network Miner. Next we had Oovoo send an image. It was also picked up in Network Miner.”

CNET reports that few of the apps had replied to requests for further information, but that Grindr had said, "We monitor and review all reports of security issues regularly. As such, we continue to evaluate and make ongoing changes as necessary to protect our users."