Watch out, Android users: Here they come again.
Last week, it was a fake version of "Angry Birds Space." Now, a new piece of malware is masquerading as Instagram, the popular photo sharing app that was only recently made available to Android users.
Like the "Angry Birds" malware before it, the Android Instagram impostor is not present in the official Android marketplace, Google Play. Rather, the Trojan horse attacks devices that download and install the fake app from unlicensed, third-party sites.
Once installed, the malicious software sends SMS messages to premium-rate numbers without the user's authorization, according to a blog post by Graham Cluley of Sophos, an Internet security company.
Cluley pointed to a Russian-language web site that purported to offer the Instagram app. "If you download your app from this site... then you are running the risk of infecting your smartphone," Cluley wrote.
Following its release, Instagram for Android was "downloaded more than one million times during the first 12 hours" it was available on Google Play, according to PC World.
Popular apps that are available for Android run a higher risk of being emulated by makers of malicious software. In a video for the Wall Street Journal's Digits blog about the "Angry Birds Space" malware last week, Ina Fried of AllThingsD said that Google's "open ecosystem" makes its Android operating system more of a target for malware than Apple's restricted iOS.
Check out the slideshow (below) for some awesome Instagram alternatives.
WATCH: Ina Fried Discusses Android Malware