Topher Kesslerof CNET wrote an interesting article about the PDF-based malware threat for the Mac OS X. Apple had released a new security update, updating its malware definition, aimed at protecting Mac users from this threat, but according to Kessler’s article, it seems to have been revised.
Here is an excerpt from his article below
Recently a new PDF-based malware threat for OS X was discovered that displays a Chinese PDF file while it installs and runs its malicious code in the background. While the initial version of this malware (OSX/Revir.A) was detected over a week ago, the criminals developing the code are busy revising and refining it, and over the weekend a variant has been identified (OSX/Revir.B). As with all malware, new versions of these threats are likely to surface in the future, and as they do, expect malware detection utilities (including Apple’s XProtect) to follow close behind and label them alphabetically as they appear.