For example, during the first quarter of 2012, the top 10 detected Android threats included the "Rage Against The Cage" exploit, the "GingerBreak" exploit, the "Exploid" exploit and the "Asroot" exploit, Botezatu said.

Some of those cases might have been caused by users who were attempting to "root" their devices. However, others were likely generated by malicious apps that used those exploits, Botezatu said.

Over 50 percent is actually a fairly conservative estimate, Oberheide said. "Yes, it's a scary number, but it exemplifies how important expedient patching is to mobile security and how poorly the industry (carriers, device manufacturers, etc) has performed thus far."

The slow deployment of security patches to Android devices is a problem that has been known of for years. Manufacturers stop issuing updates for some device models too quickly and even when they do issue updates, some carriers don't distribute them in a timely manner.

"In the Microsoft ecosystem, desktop users know that patches are provided for quite a while, just like what happened with Windows XP," Botezatu said. "Mobile carriers, on the other side, see the mobile device, as well as the operating system running atop of it as a wearable item that rapidly goes out of fashion and has a shorter lifespan than desktops or laptops."