During those two weeks, potentially harmful applications (excluding non-malicious rooting applications) were detected on 0.7 percent of devices with sideloaded apps and on under 0.1 percent of devices that only had apps from Google Play installed.
Verify Apps doesn't track the physical location of devices, but tracks the language (locale) configured on them. While the locale is not an accurate indication of device location, Google found that locale data generally reflected the expected Android user population across different countries, so it was used to draw some conclusions.
For example, devices with the Russian locale that allowed sideloading were more likely to have a potentially harmful application installed than devices with other locales. Between 3 and 4 percent of Russian devices had a PHA installed, Google said.
Their infection rate was considerably higher than that of devices with any other locale, including Chinese, whose rate was 0.8 percent. That's surprising given that Google Play is not available in China so most devices in the country are configured for sideloading.
Meanwhile, only 0.4 percent of devices that allowed sideloading and were configured with the US English locale had a PHA installed, 0.2 percent under the worldwide average, Google said.
When rooting apps were also taken into account, devices with Chinese locale jumped to the top, with a rate of around 8 percent.
"Chinese devices which install apps from outside of Google Play are more likely to have a non-malicious Rooting application than any other region or type of PHA," Google said. "In fact, there are numerous applications from major Chinese corporations that include rooting exploits to provide functionality that is not provided by the Android API. Some of these Rooting applications explicitly describe that they will use an exploit to root the device, but there are some applications which do not describe this functionality to users."
If we exclude Russia, the worldwide rate of PHA installations from outside Google Play has decreased by almost half between the first quarter and the second quarter of 2014, Google said.
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