alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Beacon Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/updates"; bsize:8; http.cookie; content:"user="; startswith; fast_pattern; pcre:"/^[A-P]{256}$/R"; http.header_names; content:!"Referer"; reference:md5,5dfb7f863cd291544b9dfdb3de25162f; reference:url,www.recordedfuture.com/chinese-group-tag-22-targets-nepal-philippines-taiwan/; classtype:trojan-activity; sid:2033290; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_07_09, deployment Perimeter, deployment SSLDecrypt, confidence Medium, signature_severity Major, tag c2, updated_at 2021_07_09, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)