alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE ELF/Emptiness v2 XOR (b2bb01039307baa2) CnC Checkin"; flow:established,to_server; dsize:24; content:"d3ec7975f76aefdbfcdc3c3e"; depth:24; fast_pattern; endswith; reference:url,blog.netlab.360.com/emptiness-a-new-evolving-botnet/; classtype:command-and-control; sid:2027836; rev:2; metadata:affected_product Linux, created_at 2019_08_09, deployment Perimeter, malware_family Emptiness, performance_impact Low, confidence High, signature_severity Major, tag DDoS, updated_at 2019_09_28;)