¿Utilizas Google, Facebook, twitter, etc, para entrar en tus cuentas a modo de contraseña?. Te interesa leer esto:
" Over 1 Billion Mobile App Accounts can be Hijacked Remotely with this Simple Hack " " .... A group of three researchers – Ronghai Yang, Wing Cheong Lau, and Tianyu Liu – from the Chinese University of Hong Kong has found [PPT] that most of the popular mobile apps that support single sign-on (SSO) service have insecurely implemented OAuth 2.0....."
http://thehackernews.com/2016/11/android-oauth-hacking.html (ingles)
Saludos.