alert http1 $HOME_NET any -> $EXTERNAL_NET any (msg:"ET RETIRED Nerbian RAT CnC Checkin"; flow:established,to_server; http.method; content:"GET"; http.uri; bsize:21; content:"/pub/health_check.php"; fast_pattern; http.user_agent; bsize:18; content:"Go-http-client/1.1"; http.header_names; bsize:39; content:"|0d 0a|Host|0d 0a|User-Agent|0d 0a|Accept-Encoding|0d 0a 0d 0a|"; reference:md5,9cca59eec5af63e42cd845b67cf6df89; reference:md5,5d5bc970f975341558b8d2c225ca0115; reference:url,twitter.com/pr0xylife/status/1519704793593307136; classtype:trojan-activity; sid:2036426; rev:5; metadata:attack_target Client_Endpoint, created_at 2022_04_29, deployment Perimeter, deployment SSLDecrypt, former_category MALWARE, performance_impact Low, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_09_12, reviewed_at 2024_09_12;)