alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Linux/Moose HTTP CnC Beacon Response"; flow:established,from_server; http.server; content:"Apache/20.2.25 (RedHat)"; fast_pattern; bsize:23; reference:url,welivesecurity.com/wp-content/uploads/2015/05/Dissecting-LinuxMoose.pdf; classtype:command-and-control; sid:2021148; rev:3; metadata:attack_target Client_Endpoint, created_at 2015_05_26, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_05_22, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)