alert tcp any any -> $EXTERNAL_NET any (msg:"ET MALWARE ELF/Mirai.shiina v3 CnC Checkin"; flow:established,to_server; content:"|01 03 03 07 04 02 00 06|"; depth:8; fast_pattern; reference:url,blog.netlab.360.com/emptiness-a-new-evolving-botnet/; classtype:command-and-control; sid:2027848; rev:1; metadata:affected_product Linux, created_at 2019_08_09, malware_family Mirai, confidence High, signature_severity Major, tag DDoS, updated_at 2019_08_09;)