alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MSIL/Agent.PYO Possible net.tcp CnC Beacon (control)"; flow:established,to_server; content:"net.tcp|3a|//"; offset:7; depth:10; pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\x3a\d+\/control\x03\x08\x0c$/R"; content:"/control|03 08 0c|"; fast_pattern; reference:url,welivesecurity.com/2015/01/29/msilagent-pyo-have-botnet-will-travel/; classtype:command-and-control; sid:2020337; rev:2; metadata:attack_target Client_Endpoint, created_at 2015_01_30, deployment Perimeter, confidence Medium, signature_severity Major, tag c2, updated_at 2019_10_08, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)