alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Suspicious Windows NT version 1 User-Agent"; flow:established,to_server; http.user_agent; content:"Windows NT 1"; fast_pattern; nocase; content:!"0"; within:1; pcre:"/^[^0-9]/R"; classtype:bad-unknown; sid:2015898; rev:7; metadata:created_at 2012_11_20, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_17;)