alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET CURRENT_EVENTS [Fireeye] Backdoor.HTTP.BEACON.[Yelp GET]"; flow:established,to_server; content:"request_origin=user"; http.method; content:"GET"; http.request_line; content:"&parent_request_id="; within:256; fast_pattern; content:"|20|HTTP/1"; within:1024; pcre:"/^GET [^\r\n]{0,256}&parent_request_id=(?:[A-Za-z0-9_\/\+\-%]{128,1024})={0,2}[^\r\n]{0,256} HTTP\/1\.[01]/"; http.header; content:"|0d 0a|Sec-Fetch-Dest|3a 20|empty|0d 0a|"; reference:url,github.com/fireeye/red_team_tool_countermeasures; classtype:trojan-activity; sid:2031280; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_12_08, deployment Perimeter, confidence High, signature_severity Major, tag c2, updated_at 2020_12_09, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)