Google has removed nearly two dozen malware-infected apps from its official Android Market in the last several days, a security company said Sunday.
So far this year, Google has yanked more than 100 malicious Android apps from its download distribution channel.
San Francisco-based Lookout Security said that it and other vendors had notified Google of several recent waves of malicious apps -- 22 apps altogether -- that reached the Android Market. Google has yanked those programs from the e-mart, said Lookout.
Lookout spotted nine malware-infected apps last week, and another 13 over the weekend.
The company dubbed the malware bundled with the fake apps "RuFraud," and said that the code sent spurious text messages to premium numbers, racking up revenues for the criminals.
While North American users were not affected -- RuFraud was written not to target the U.S., for instance -- people in France, Germany, Italy, Poland, Russia, the U.K. and several other eastern European and central Asian countries were.
As in previous malicious app campaigns, the RuFraud apps borrowed elements of legitimate apps, but did not simply snatch complete apps, then re-package them with malicious code, said Lookout.
"They borrowed aspects of other apps, including terminology and in some cases identical text," said Tim Wyatt, a principal engineer at Lookout.
The recent RuFraud operations began with horoscope apps, said Lookout, then moved on to Android phone wallpapers -- including one for the Twilight series of movies -- and downloaders posing as accessories to bestselling games such as "Angry Birds" and "Cut the Rope," then finished with a round of fake games, Lookout's researchers said.
That last run accounted for the majority of downloads before Google pulled the apps. Lookout estimated that about 14,000 copies of the fake games were grabbed by users.
"A couple of instances of the apps from this weekend really drove that [number]," added Derek Halliday, a Lookout senior security product manager. "The others really didn't affect very many people as far as we know."
Both Lookout and Google -- the latter in an email from a spokesman -- pointed out that the fraudulent apps declare possible SMS charges in their terms of service, and in the permissions users grant. "It's not possible for a user to install the app without approving this permission to allow the app to send premium SMS messages," said the Google spokesman.