alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Activity (GET)"; flow:established,to_server; http.request_line; content:"GET /azure/v2/api HTTP/1.1"; fast_pattern; http.user_agent; content:"MusicBee/3.4"; bsize:12; http.header_names; content:!"Referer"; content:"|0d 0a|Host|0d 0a|Connection|0d 0a|Cache-Control|0d 0a|"; startswith; http.cookie; content:"HSID="; startswith; reference:url,twitter.com/Unit42_Intel/status/1470778363254128651; reference:md5,b873bfa8dec8c3a1f62c30903e59e849; classtype:trojan-activity; sid:2034726; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_12_14, deployment Perimeter, malware_family CobaltStrike, confidence Medium, signature_severity Major, tag c2, updated_at 2021_12_14, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)