alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/siteindex/b/?filter="; startswith; fast_pattern; http.user_agent; content:"Mozilla/5.0 (Windows NT 6.1) AppleWebKit/587.38 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/"; http.header_names; content:!"Referer"; http.connection; content:"Close"; reference:url,twitter.com/StopMalvertisin/status/1533651010111307776; reference:url,cert.gov.ua/article/40559; classtype:trojan-activity; sid:2036876; rev:2; metadata:attack_target Client_Endpoint, created_at 2022_06_06, deployment Perimeter, deprecation_reason Age, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2024_12_02, reviewed_at 2024_12_02, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;)