From sources all over the internet, Adobe made a sent out a Security bulletin yesterday:
APSA09-01 (Buffer overflow issue in versions 9.0 and earlier of Adobe Reader and Acrobat)
[ad#ad2-right]A critical vulnerability has been identified in Adobe Reader 9 and Acrobat 9 and earlier versions. This vulnerability would cause the application to crash and could potentially allow an attacker to take control of the affected system. There are reports that this issue is being exploited.
Adobe Plans on patching this March 11, 2009
and According to some other reports are saying:
Symantec Security Response has received several PDF files that actively exploit a vulnerability in Adobe Reader. We are continuing to remain in contact with Adobe on this vulnerability in order to ensure the security of our mutual customers.
[via Symantec]
With PDF files being used all over the business world, this will create undo problems with the IT Field. This also could be used to make Botnets and make the network involved become sluggish. It must be warned that there are a whole wide variety of possibilities that could be done with this exploit. Shadowserver Foundation recommends disabling the Javascript in your Adobe Reader. Until the patch comes out you will need to be careful on what you open up and possibly check each and every PDF with an Anti-virus. This should help minimize the likely hood of getting a virus or Trojan, but is not going to be a 100%. The only way you can prevent a 100% right now is not to use PDFS until they have Fixed this problem.