alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MSIL/GravityRAT CnC Checkin M2"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php"; endswith; http.request_body; content:"signatureHash="; fast_pattern; content:"signatureString="; content:"userName="; content:"pcName="; content:"macId="; content:"cpuId="; content:"agent="; reference:url,securelist.com/gravityrat-the-spy-returns/99097/; classtype:command-and-control; sid:2031061; rev:2; metadata:attack_target Client_Endpoint, created_at 2020_10_19, deployment Perimeter, malware_family GravityRAT, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_19;)