Last year saw solid improvement for Android security, according to Google's Android Security 2016 Year in Review report, which was released March 22. The 71-page report provides extensive details on Google's progress on improving update rates, detecting potential risks and reducing the number of potentially harmful applications (PHAs) on Android devices.
"A lot of the things that are in the report are the result of grinding work, where we're thinking about how we protect an ecosystem that is a big and complicating thing," Adrian Ludwig, director of Android security at Google, told eWEEK.
Among the interesting trends found in the report is that the volume of Android devices that have PHAs is now less than 1 percent overall, Ludwig said. For Android devices with apps that have only been installed from Google Play, the volume of PHAs in 2016 was 0.06 percent, down from 0.28 percent in 2015. Looking specifically at apps that were installed outside of Google Play, the PHA percentage rate varied over the course of 2016, reaching a low of 1.38 percent in December. Ludwig said that the lower rates of PHAs are due to Google's improved detection capabilities and machine learning improvements.
Ludwig is also proud of the continued improvement in update rates for devices. Google introduced a monthly patching cycle in August 2015 after the Stagefright vulnerability was publicly disclosed. However, not every carrier and handset vendor makes updates available to end users as quickly as Google does for its Nexus and Pixel devices.
At the end of 2016, approximately 78 percent of flagship Android devices in North America were up to date, according to Google's data. Google isn't completely sure what the update rate for flagship devices was at the beginning of 2016, though Ludwig estimates it was roughly 10 percent.
"More broadly we saw approximately 750 million Android devices receive security updates in 2016," he said. "I think that's a significant amount of progress over where we were previously, but that's an area where we will continue to make investments and progress in 2017."
Google started its monthly patch cycle for Android in the aftermath of the Stagefright Android mediaserver vulnerability in 2015. In the report, Google details the lengths that the company has gone with the Android Nougat (7.x) update to improve and secure the mediaserver. Yet despite those improvements, mediaserver vulnerabilities continue to be disclosed and patched in Android. In Google's March 2017 security update, 18 mediaserver flaws were patched.
Ludwig explained that Google is still providing patches for Android versions 4.4.4 and higher.
"If the issue is potentially exploitable on any of the supported devices, then we make a patch available for all of them," he said.
Many of the changes in the more recent versions of Android have been to make the mediaserver code less accessible and therefore harder to exploit, according to Ludwig.
Another area of risk that continues to be a challenge is third-party components that are part of Android devices. In the March 2017 update, for example, there were 35 patches for vulnerable Qualcomm components in Android. Ludwig said third-party component risk is an area that Google, together with partners, is working on to improve.
In 2017, Ludwig is confident that Google will continue to improve Android security.
"I believe we now have sufficiently sophisticated machine learning and neural network-based models that we can fundamentally change the economics of malware distribution," he said.