http://nmap.org/download.html#macosx

How to Scan a Windows Network for Conficker Virus from Mac OS X:

Use nmap to search your LAN for vulnerabilities to Conficker by using the following command:

nmap -PN -T4 -p139,445 -n -v—script=smb-check-vulns—script-args safe=1 192.168.0.1-254

Note: Substitute the IP range for your LAN, so this may be something other than the IP range above, like 10.1.1.10-100

http://osxdaily.com/2009/03/31/how-to-scan-a-windows-network-for-conficker-virus-from-mac-os-x/