alert http1 $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE NimPlant Register Activity M2 (POST)"; flow:established,to_server; urilen:9; http.method; content:"POST"; http.uri; content:"/register"; http.accept_enc; bsize:4; content:"gzip"; http.header; content:"|0d 0a|X-Identifier|3a 20|"; fast_pattern; pcre:"/^[a-zA-Z]{8}\r\n/R"; http.request_body; content:"|7b 22|data|22 3a 22|"; startswith; http.header_names; content:"|0d 0a|User-Agent|0d 0a|X-Identifier|0d 0a|Content-Length|0d 0a|Host|0d 0a 0d 0a|"; content:!"Referer"; reference:url,github.com/chvancooten/NimPlant; classtype:trojan-activity; sid:2044349; rev:3; metadata:attack_target Client_Endpoint, created_at 2023_02_27, deployment Perimeter, performance_impact Moderate, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_03; target:src_ip;)