It's a hoax.
Norton has got it taped. . [quote] . .Symantec Security Response encourages you to ignore any messages regarding this hoax. It is harmless and is intended only to cause unwarranted concern. . .<hr></blockquote>
Details at:. .<a href="http://securityresponse.symantec.com/avcenter/venc/data/sulfnbk.exe.warning.html" target="_blank">http://securityresponse.symantec.com/avcenter/venc/data/sulfnbk.exe.warning.html</a>