MAC Defender, a fake antivirus software was discovered by Intego (security firm) on Monday. The fake antivirus software shows the infected user that it has found viruses on the Mac, and in order to get rid of the viruses one would need to buy the Mac Defender software. If an inexperienced user bought this program it could possibly end up taking the user's credit card information and send it off to scammers. The creators of Mac Defender have also used SEO poisoning to pump up the ranking of the Mac Defender website in order to make the unsuspecting user think it is a legit website and program. If a user visits the malicious webpage a window will appear and tell the user they have been infected and an automatic download of Mac Defender will show up asking the user to unzip and install the file. You can help to prevent yourself from accidently executing a malicious file by making sure your web browser is not set to automatically open downloaded files.