alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ThreatFox botnet C2 traffic (url - confidence level: 90%)"; flow:established,from_client; http.method; content:"GET"; http.uri; content:"/attest/challenge"; depth:17; nocase; http.host; content:"bulbous-bouffant.metalseed.net"; depth:30; isdataat:!1,relative; reference:url, threatfox.abuse.ch/ioc/1781065/; target:src_ip; metadata:confidence_level 90, first_seen 2026_04_06; classtype:trojan-activity; sid:91781065; rev:1;)