alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32.Netwire Connectivity Check"; flow:to_server,established; urilen:1; http.method; content:"GET"; http.user_agent; content:"Mozilla/4.0 (Windows NT 6.1|3b| WOW64|3b| Trident/7.0|3b| rv|3a|11.0) like Gecko"; endswith; http.host; content:"checkip.dyndns.org"; endswith; fast_pattern; http.header_names; content:!"Referer|0d 0a|"; reference:url,malpedia.caad.fkie.fraunhofer.de/details/win.netwire; classtype:trojan-activity; sid:2034089; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_10_01, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_10_01, reviewed_at 2023_08_22;)