Angry Birds might be stealing money from you — if you got it from shady sources.

Polygon reports that some cracked versions of Angry Birds contain malware that can steal virtual currency from unfortunate downloaders. These versions are said to be spreading around popular downloading websites like download.com and macupdate.com.

The culprit, called the OSX/CoinThief Trojan, is said to be deliberately attached with some cracked copies of Angry Birds but has also been detected with other popular apps. Some of the apps reported to be infected aside from Angry Birds are cracked versions of the media app Delicious Library, graphics app Pixelmator and text-editing app BBEdit.

The malware installs itself to a device running on Mac OS X and hacks Bitcoin wallets through malicious add-ons that steal login credentials of Bitcoin accounts. Most likely to become victims of the Angry Birds trojan are those from the US, according to analytics provided by ESET Live Grid. SecureMac was first to discover the modus operandi of the bitcoin thieves.

Why are virtual thieves using Angry Birds?

In an interview with Polygon, AVG security advisor Michael McKinnon said that aside from Angry Birds being extremely popular, people who download Angry Birds would likely be the same people who have bitcoin accounts.

He says the demographics for bitcoin users and mobile gamers are the same, making them the ideal target for bitcoin heists.

Whether the app is cracked or not isn’t the main security issue, according to McKinnon. He say unless the app comes from its official website or a trusted app market, it is virtually impossible to tell if an app is safe for use or not.

AVG and other security software companies advise Mac OS X users to always update anti-virus softwares to ensure that their devices are safe from these types of schemes.

Both the Mac and the Bitcoin communities were kept abuzz by the trojan scare. Some blamed software pirates for the spread of the CoinThief trojan while others mockingly endorsed Dogecoin over Bitcoin. There were also many who were sympathetic with those who got victimized by the Angry Birds malware.

The bitcoin-stealing malware was fairly successful despite the fact that the virtual currency is experiencing a continued decline with its popularity. Only this weekend, Bitcoin exchange Mt. Gox applied for bankruptcy protection in Tokyo, admitting to have lost an estimated 850,000 bitcoins or $500 million dollars during the course of their operation.

Malware infection isn’t the only controversy linked with Angry Birds in the recent weeks. Only last month, a much larger issue was uncovered when Edward Snowden revealed that the NSA is using Angry Birds to collect data from its players.

[Image from Waleed Alzuhair via Flickr]