Researchers at Trend Micro recently discovered new Android-based malware called Godless, which targets devices running Android Lollipop or earlier.
As Trend Micro points out, that covers almost 90 percent of Android devices.
"Based on the data gathered from our Trend Micro Mobile App Reputation Service, malicious apps related to this threat can be found in prominent app stores, including Google Play, and has affected over 850,000 devices worldwide," the company said in a statement.
According to Trend Micro, Godless uses a framework called "android-rooting-tools" to gain root access to Android-based devices. From there, the malware phones home and receives instructions from its creators. Trend Micro says Godless often surreptitiously downloads unwanted apps, and is capable of displaying malicious ads. It can also install backdoors and "spy on users," the researchers say.
Godless has evolved, researchers said. "Recently, we came across a new Godless variant that is made to only fetch the exploit and the payload from a remote command and control (C&C) server," they said. "We believe that this routine is done so that the malware can bypass security checks done by app stores, such as Google Play."
Trend Micro points to an app known as Summer Flashlight as one that was malicious; it does not appear to be live in Google Play anymore.
"We have also seen a large amount of clean apps on Google Play that has corresponding malicious versions—they share the same developer certificate—in the wild," Trend Micro says. "The versions on Google Play do not have the malicious code. Thus, there is a potential risk that users with non-malicious apps will be upgraded to the malicious versions without them knowing about apps' new malicious behavior."
That is a violation of the Google Play's terms and conditions, Trend Micro notes.
Looking ahead, Trend Micro warned Android users to "review the developer" when downloading apps. "Unknown developers with very little or no background information may be the source of these malicious apps," it wrote.