With all the unknown variants out there, you need to follow the "PREVENTION AND AVOIDANCE" found on the technical details page.
http://www.symantec.com/security_response/writeup.jsp?docid=2008-080315-0217-99&tabid=2
I suggest upgrading off the old AV engine ASAP.
Let me start out by saying that you are using an old AV product. SAV only provides Antivirus, and these days you need a lot more than just AV.
You need to upgrade to our Endpoint Protection product for more security. SEP provides Firewall, IPS, Application & Device control and more.
Symantec Endpoint Protection Technologies Explained - http://www.symantec.com/business/support/index?page=content&id=TECH166816
The New SEP - http://www-uat.ges.symantec.com/business/theme.jsp?themeid=sep-family
The Koobface worm spreads through social networking sites, so user education is key to helping minumize the risk off infection. Blocking these sites in a workplace environment is your safest bet, but most companies these days need access to Social sites.
Follow the Security Best Practices for Protecting a Business Environment from Common Threats - http://www.symantec.com/business/support/index?page=content&id=TECH105236
W32.Koobface write-up - http://www.symantec.com/security_response/writeup.jsp?docid=2008-080315-0217-99
I hope this info is helpful.
