alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE JS/Z1_Loader Activity (POST)"; flow:established,to_server; urilen:1; http.method; content:"POST"; http.request_body; bsize:4; content:"id=1"; fast_pattern; http.host; pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/"; http.header_names; strip_pseudo_headers; to_lowercase; content:"|0d 0a|accept|0d 0a|accept-language|0d 0a|accept-encoding|0d 0a|"; startswith; content:!"|0d 0a|referer|0d 0a|"; reference:md5,1740dd861c10c370aded27ff14fa8425; classtype:trojan-activity; sid:2049086; rev:3; metadata:attack_target Client_Endpoint, created_at 2023_11_06, deployment Perimeter, malware_family JS_Z1_Loader, performance_impact Moderate, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_30, reviewed_at 2023_11_06; target:src_ip;)