alert udp $EXTERNAL_NET any -> $HOME_NET [137,138,139,445] (msg:"ET SCAN Nessus Netbios Scanning"; content:"n|00|e|00|s|00|s|00|u|00|s"; fast_pattern; reference:url,www.tenable.com/products/nessus/nessus-product-overview; classtype:attempted-recon; sid:2015754; rev:3; metadata:created_at 2012_10_01, confidence Medium, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_10_08;)