alert tcp $HOME_NET any -> $EXTERNAL_NET 27 (msg:"ET MALWARE ELF/Samba CnC Checkin"; flow:established,to_server; dsize:8; content:"|11 10 10 01 22 32 21 52|"; fast_pattern; reference:url,www.guardicore.com/2018/11/butter-brute-force-ssh-attack-tool-evolution; classtype:command-and-control; sid:2026717; rev:1; metadata:affected_product Linux, attack_target Client_Endpoint, created_at 2018_12_10, deployment Perimeter, malware_family Samba, performance_impact Low, confidence Medium, signature_severity Major, updated_at 2019_07_26;)