Canada and its spying partners exploited weaknesses in one of the world's most popular mobile browsers and planned to hack into smartphones via links to Google and Samsung app stores, a top secret document shows.

Electronic intelligence agencies began targeting UC Browser in late 2011 after discovering it leaked revealing details about its half-billion users. Their goal, in tapping into UC Browser and also looking for larger app store vulnerabilities, was to collect data on suspected terrorists and other intelligence targets — and, in some cases, implant spyware on targeted smartphones. The surveillance agencies exploited the weaknesses in certain mobile apps.