It's based on the open source ClamAV application. The following free antivirus apps are listed in order of the Mac hardwareĪnd operating systems they support, going from the oldest to the newest.ĬlamXav may be the oldest OS X antivirus software inĮxistence. Mac OS X Viruses Free Mac OS X Antivirus Software Information on viruses for the Classic Mac OS, see Classic Mac OS Viruses. This page only covers malware for Mac OS X.