It's not often that you hear of a virus for the Mac, but according to a Secure Mac security bulletin, a new trojan virus has been detected on the Mac. The bulletin notes that the virus is spread through social networking websites like Facebook and is disguised as a video.

The trojan called "trojan.osx.boonana.a" has been wreaking havoc on both Windows and Mac platforms.

Secure Mac says, "When a user clicks the infected link, the trojan initially runs as a Java applet, which downloads other files to the computer, including an installer, which launches automatically. When run, the installer modifies system files to bypass the need for passwords, allowing outside access to all files on the system. Additionally, the trojan sets itself to run invisibly in the background at startup, and periodically checks in with command and control servers to report information on the infected system. While running, the trojan horse hijacks user accounts to spread itself further via spam messages. Users have reported the trojan is spreading through e-mail as well as social media sites."

This is a cross-platform virus due to the Java code that can be executed on both Windows and Mac operating systems. Secure Mac gives us some tips for protecting your computer from this virus. The first tip is to turn off Java execution in your web browser. You can do this in Safari by navigating to Safari > Preferences > Security Tab and unchecking the "Enable Java" checkbox.

Additional tips from Secure Mac includes:

1. Watch where you surf. By sticking with safe, well-known websites, you will be less likely to visit a site that will attempt to infect you with a trojan horse. Be especially careful when surfing to links included in messages on social media sites, even if they come from a friend.
2. Watch what you download. Download files only from trusted sources and safe sites.

3. Use security features in OS X. Turn on the built-in Firewall, and consider security software, especially when a computer is shared by multiple users.

If you believe your Mac is infected with this virus, you can download and run the free removal tool from Mac Scan on the Secure Mac website. You can also read more about this virus on that website.

Follow this article's author, Cory Bohon on Twitter.