alert http $HOME_NET any -> $EXTERNAL_NET any (
msg:"ET MALWARE NimPlant Register Activity (GET)";
flow:established,to_server;
urilen:9;
flowbits:set,ET.nimplant;
flowbits:noalert;
http.method;
content:"GET";
http.uri;
content:"/register"; fast_pattern;
http.header_names;
content:!"Referer";
reference:url,github.com/chvancooten/NimPlant;
classtype:trojan-activity;
sid:2044347; rev:1;
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 2023_02_27;
target:src_ip;
)