alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE DoS.Linux/Elknot.G Checkin"; flow:established,to_server; dsize:401; content:!"|00 00|"; depth:2; content:"|00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|Linux|20|"; offset:2; depth:21; fast_pattern; pcre:"/^\d/R"; reference:md5,917a2a3d8c30282acbe7b1ff121a4336; classtype:command-and-control; sid:2018808; rev:2; metadata:created_at 2014_07_30, confidence High, signature_severity Major, updated_at 2022_03_17, reviewed_at 2024_03_15;)