The full research paper was not immediately available, but the authors did post an . In analyzing the use of SSL in 13,500 popular free apps on Google Play, the researchers found 1,074 vulnerable to MITM attacks.

The researchers, who worked in teams from the Leibniz University in Hanover and Philipps University of Hamburg, used a homegrown proof-of-concept tool called MalloDroid, which was designed to identify exploitable SSL bugs, Threatpost, the Kaspersky Lab blog, . The apps analyzed with the tool represented 17% of the apps that contain HTTPS URLs, which indicate that they use SSL.

The researchers manually audited 100 apps and found 41 vulnerable to MITM attacks because of SSL misuse. The cumulative install base of all the vulnerable apps ranged between 39.5 million and 185 million users, based on information the researchers gathered from Google Play.

"The actual number is likely to be larger, since alternative app markets for Android also contribute to the install base," the researchers said.

From the 41 apps analyzed manually, the researchers were able to capture credentials for American Express, Diners Club, Paypal, bank accounts, Facebook, Twitter, Google, Yahoo, Microsoft Live ID, Box, WordPress, remote control servers, arbitrary email accounts and IBM Sametime. In addition, the researchers were able to disable anti-virus apps and remotely inject and execute code.