In this paper (PDF), the researchers from Leibniz University in Hannover and Philipps University of Marburg found that 17 percent of the SSL-using apps in their sample suffered from implementations that potentially made them vulnerable to man-in-the-middle MITM attacks.
They state that they were “able to capture credentials from American Express, Diners Club PayPal, bank accounts, Facebook, Twitter, Google, Yahoo, Microsoft Live ID, Box, WordPress, remote control servers, arbitrary e-mail accounts, and IBM Sametime”.
In addition, since virus software also uses SSL, “We were able to inject virus signatures into an anti-virus app to detect arbitrary apps as a virus or disable virus detection completely.”