alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Activity (GET)"; flow:established,to_server; http.request_line; content:"GET /EbhM HTTP/1.1"; fast_pattern; http.user_agent; content:"Mozilla/5.0|20|(compatible|3b 20|MSIE|20|9.0|3b 20|Windows|20|NT|20|6.0|3b 20|Trident/5.0)"; bsize:63; http.host; pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/"; http.header_names; content:!"Referer"; reference:md5,72dac7c7f9c50d8ab420acb75132f631; reference:url,twitter.com/BlackLotusLabs/status/1456314419215020043; classtype:trojan-activity; sid:2034346; rev:2; metadata:attack_target Client_Endpoint, created_at 2021_11_05, deployment Perimeter, deployment SSLDecrypt, confidence Medium, signature_severity Major, tag c2, updated_at 2021_11_05, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)