In the past, most malware writers have targeted systems running Microsoft's Windows operating system. This has led many Mac users to believe falsely that OS X is a highly secure operating system that can't be compromised. As a result, most computers running the operating system have little or no malware protection. The Flashback Trojan, however, demonstrated that machines running Apple's OS X operating system are also now being targeted, and that they are vulnerable.
Aside from vulnerabilities in the operating system, which Apple is often slow to patch, malware writers are also exploiting vulnerabilities in software such Java. Flashback infected over 600,000 systems running OS X. The report predicts that because most OS X systems have little or no protection and the user base is inexperienced with security, it will increasingly be targeted by attackers in the future.
What you can do to mitigate the threat: Devices running OS X should be protected by the same security measures as Windows machines. That means installing antivirus software, and ensuring that the operating system and third-party software such as Java is updated with security patches as soon as they are available.
The security threat landscape changes constantly, with malicious hackers developing new ways to compromise your systems as older vulnerabilities are discovered and patched. So it's important to be aware of the threats to enterprise security that are coming over the horizon and heading this way.