Researchers have unearthed dozens of Android apps in the official Google Play store that expose user passwords because the apps fail to properly implement HTTPS encryption during logins or don't use it at all.

The roster of faulty apps have more than 200 million collective downloads from Google Play and have remained vulnerable even after developers were alerted to the defects. The apps include the official titles from the National Basketball Association, the Match.com dating service, the Safeway supermarket chain, and the PizzaHut restaurant chain. They were uncovered by AppBugs, a developer of a free Android app that spots dangerous apps installed on users' handsets.

AppBugs CEO Rui Wang told Ars that the Match.com app uses unencrypted hypertext transfer text protocol when sending user passwords, making it trivial for people in a position to monitor the traffic—such as someone on the same Wi-Fi network—to read the credentials. Other apps, such as NBA Game Time and those from Safeway and PizzaHut use HTTPS encryption but don't implement it correctly. As a result, a man-in-the-middle attacker can use a self-signed or otherwise fraudulent digital certificate to read the login data.

"As shown in the video demo, when the victim user logs into his League Pass account in the app, a third party machine will be able to grab the password and username," Wang wrote in an e-mail. "The attacker could be some stranger who monitors the traffic of a public Wi-Fi or a compromised router on the Internet which logs the traffic quietly."

Wang said the NBA app requires an NBA League Pass Account, which according to this official NBA video costs $199. He said his company reported the vulnerability to the app developer in late February but never got a response. The developers of the Match.com, Safeway, and PizzaHut apps, as well as more than 50 other apps, similarly failed to respond. In all, Wang said he discovered 100 apps that didn't HTTPS-protect login credentials, only 28 of which have since been fixed.

Although it wouldn't be hard for Google to detect such shortcomings in the apps it makes available on its own servers, there's no indication that the company does that. The results come a couple months after student researchers at City College of San Francisco found Android apps collectively downloaded at least 350 million times suffered similarly fatal HTTPS flaws . They also come after a critical bug in a popular code library for iOS developers caused fatal HTTPS failures in an estimated 1,500 apps for iPhones and iPads. The results make it clear that Android users, and to some extent, iOS users too, are on their own when it comes to ensuring the safety of the apps they install on their devices.

Post updated to add details about https in iOS apps.