alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Backdoor.Elise CnC Beacon 3 M1"; flow:to_server,established; http.method; content:"GET"; http.uri; content:"/archive/"; nocase; offset:9; fast_pattern; content:".html"; nocase; distance:8; within:7; pcre:"/\/[a-f0-9]{8}\/archive\/\d{8,10}\.html$/i"; http.header_names; content:!"Accept-"; content:!"Referer|0d 0a|"; reference:md5,cf3f36dd3235d2cff5754b19b9e1cb1f; reference:url,github.com/pan-unit42/iocs/tree/master/lotusblossom; classtype:command-and-control; sid:2021277; rev:5; metadata:attack_target Client_Endpoint, created_at 2015_06_16, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_05_28, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)