Google and Samsung App Stores Targeted by the NSA
All you guys who like conspiracy theories are going to love this one: recent reports based on Snowden's leaked files indicate that the NSA had plans to infect the Google and Samsung app stores with malware capable of hijacking information from the users' devices. According to the aforementioned documents, the National Security Agency held a series of workshops on this project with the participation of their counterparts from the U.K., Australia, New Zealand and Canada. Collectively, the five agencies would call themselves the "Five Eyes".
From what I understand, the plan was to interfere in the connection between the user and the store and plant malicious code which would then innocently collect data and even send selective misinformation to the targets if the agencies needed to create some confusion. Unfortunately, according to the leaked file, this project was planned for a few years ago, but we are only now finding out about. Even though there is no way for us, the little people, to know what actually happened with this initiative, the fact that UK's GCHQ actually designed spying software capable of working on Android and iOS is well documented.
Snowden's document also indicated a vulnerability in the UC Browser (an application highly popular in China) which was used by the NSA and other security agencies for years. By exploiting this flaw they were able to obtain phone numbers, SIM card numbers and many details regarding the Chinese servers. This went on until April this year, when a human rights group named Citizen Lab notified Alibaba (the developer) about what was going on. The Chinese company officially stated that it never received any kind of report about an information leak from security agencies.