alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE NimPlant Register Activity (GET)"; flow:established,to_server; flowbits:set,ET.nimplant; flowbits:noalert; urilen:9; http.method; content:"GET"; http.uri; content:"/register"; fast_pattern; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; reference:url,github.com/chvancooten/NimPlant; classtype:trojan-activity; sid:2044347; rev:3; metadata:attack_target Client_Endpoint, created_at 2023_02_27, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_29; target:src_ip;)