There appears to be active exploitation of an issue patched by Symantec back in May 2006

New Botnet impacts Symantec Client Port 2967
http://www.incidents.org/diary.php?storyid=1892

Symantec Client Security and Symantec AntiVirus Elevation of Privilege
http://www.symantec.com/avcenter/security/Content/2006.05.25.html

QUOTE: We've received reports of a massive new outbreak of bots exploiting the Symantec Client Security and Antivirus escalation of privilege vulnerability.  ("new" implying the outbreak, not the vulnerability