alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Beacon Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/topstories"; bsize:11; fast_pattern; http.cookie; content:"__cfduid="; startswith; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/R"; http.user_agent; content:"Mozilla/5.0|20 28|Windows NT 6.1|29 20|Gecko/14.0|20|Firefox/14.0"; bsize:52; reference:md5,432e0676db09997f78e133263737b401; reference:url,documents.trendmicro.com/assets/white_papers/wp-earth-baku-an-apt-group-targeting-indo-pacific-countries.pdf; classtype:trojan-activity; sid:2033927; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_09_13, deployment Perimeter, deployment SSLDecrypt, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2021_09_13, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;)