This is the scariest:

Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.

>>Hi Tamar,
>>
>>The headers do not accurately portray the originator of the virus with this one because it uses spoofing. See:
>>
>>http://securityresponse.symantec.com/avcenter/venc/data/w32.sobig.f@mm.html
>
>The From address is spoofed, but I'm actually reading the email headers and pulling the computer name out of the last Received line. I'm pretty sure that's not being spoofed, particularly because the prior thread I started on this subject resulted in another machine getting cleaned up.
>
>Tamar