There are thousands of apps in the Google Play mobile market that contain serious mistakes in the way that SSL/TLS is implemented, leaving them vulnerable to man-in-the-middle attacks that could compromise sensitive user data such as banking credentials, credit card numbers and other information. Researchers from a pair of German universities conducted a detailed analysis of thousands of Android apps and found that better than 15 percent of those apps had weak or bad SSL implementations. The researchers conducted a detailed study of 13,500 of the more popular free apps on Google Play, the official Android app store, looking at the SSL/TLS implementations in them and trying to determine how complete and effective those implementations are. What they found is that more than 1,000 of the apps have serious problems with their SSL implementations that make them vulnerable to MITM attacks, a common technique used by attackers to intercept wireless data traffic. In its research, the team was able to intercept sensitive user data from these apps, including credit card numbers, bank account information, PayPal credentials and social network credentials.