Hello,
Thank you pete for suggesting my Advice.
This has been a Latest Trend after Adobe vulnerability was found.
I would also suggest a read though the latest Symantec Security Response Blogs'
Adobe Reader Zero-day being exploited in the wild
https://www-secure.symantec.com/connect/blogs/adobe-reader-zero-day-being-exploited-wild
A New Zero Day PDF Exploit used in a Targeted Attack\
Hope that helps!!