alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE [eSentire] Cobalt Strike Beacon"; flow:established,to_server; http.method; content:"GET"; http.user_agent; content:"|43 6f 62 61 6c 74 20 53 74 72 69 6b 65 20 42 65 61 63 6f 6e 29|"; fast_pattern; endswith; http.header_names; content:!"Referer"; classtype:targeted-activity; sid:2025635; rev:5; metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2018_07_03, deployment Perimeter, confidence High, signature_severity Major, tag c2, updated_at 2020_11_19, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)