alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE ELF/Emptiness v2 XOR DNS Flood Command Inbound"; flow:established,from_server; content:"|fe d6 53 76 f0 7e fb|"; depth:7; fast_pattern; pcre:"/^[\x20-\x7e\r\n]{0,13}[^\x20-\x7e\r\n]/"; reference:url,blog.netlab.360.com/emptiness-a-new-evolving-botnet/; classtype:trojan-activity; sid:2027844; rev:1; metadata:affected_product Linux, created_at 2019_08_09, malware_family Emptiness, confidence Medium, signature_severity Major, tag DDoS, updated_at 2019_08_09;)