alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Ironhalo CnC Beacon"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".php"; endswith; http.user_agent; content:"Mozilla/4.0(compatible|3b|MSIE 8.0|3b|Windows NT 6.1)"; fast_pattern; bsize:47; http.header_names; content:!"Accept-"; content:!"Referer|0d 0a|"; reference:url,fireeye.com/blog/threat-research/2015/12/the-eps-awakens-part-two.html; classtype:command-and-control; sid:2022298; rev:3; metadata:attack_target Client_Endpoint, created_at 2015_12_22, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_06_16, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)