Google pulls Trojanized Android apps, and researchers warn of malware in alternative Android markets in China and of an Android version of the Zitmo banking Trojan.
Mobile security firm Lookout reports that about two dozen apps were found to contain malware. Google has not yet commented.
Company pulls 21 mobile apps from its Android Market and people's Android devices after finding they were infected with malware called DroidDream, according to enthusiast sites.
Google is forced to remove more than 50 apps this week, prompting one security expert to suggest using antivirus scanning in the Android Market.
Apps infected with malware grew five-fold since January, Lookout mobile threat report finds.
Someone has modified a version of software Google released to clean up infected Android phones and released it on an unregulated marketplace in China, Symantec says.
Internet giant says it removed several rogue apps from the Android Market and will remove them from affected users' devices.
Modern mobile devices don't suffer the same vulnerabilities as PCs, and those selling antivirus software for Android, iOS, and BlackBerry OS shouldn't be trusted.
The malware is launched after a user tries to place a call. The conversation is stored in the .amr file format, research at CA say.
The popularity and openness of Google's mobile OS has led to a 90 percent jump in malware targeting Android devices this year, says security vendor Fortinet.