MacDefender isn’t a virus, but a fake antivurus that tries to get you to install it to your system. If it succeeds, it then either tells you your system has already been infected, or shows you fake evidence that your system already has a virus. It asks you to buy the full version of MacDefender with your credit card to fix all your problems and get your Mac running normally again. Apple wasn’t going to let their dedicated users suffer for very long. They first released a set of instructions showing how to avoid downloading MacDefender, as well as how to remove it. Later they created a patch available through download to help protect their dedicated users, and keep their Apple products safe. To download the patch to eliminate the possibility of downloading the MacDefender software and having it affect your system, do the following:
Choose “Software Update” under the Apple menu. This will call up a listing of any software that needs to be updated or patched, including “Security Update 2011-003,” the necessary patch dealing with MacDefender.
Be sure to select all of the software you want installed, including the Security Update. After telling the Update to install, it will ask for your administrator password. You won’t be able to make these changes without it.
If you have selected to update software that requires your computer to restart, it will alert your system at this point that it will restart. However, the Security Update itself does not require you to do a restart.
After installing the Security Update, start the System Preferences application and open the Security pane. Click the padlock in the lower left of the screen and again type in your System Administrator password to unlock it to make changes. However, “Automatically update safe downloads list” should already be checked. Installing this Security Update and checking to automatically update the safe downloads list will have a dual affect on your system. MacDefender has now been added to the list of known malware, and every time you download a file it will make sure that it doesn’t contain MacDefender or any other known malware. If it does find it, it will alert you with a warning message, telling you the file you downloaded will damage your computer, and asking you to move it to the trash. Additionally, with this Security Update, a daily check will be instituted to check for new additions to the malware list. Previously, only updates to OS X and security updates would have done that, but now it will happen on a daily basis. It will also check your system at this time for MacDefender, and if it’s found, it will be removed.
