alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE njRAT/Bladabindi Variant (Lime) CnC Checkin"; flow:established,to_server; dsize:<250; content:"|00|ll"; within:6; content:"TGltZV8"; within:30; fast_pattern; pcre:"/^[0-9]{2,3}\x00\x6c\x6c(?P<var>[\x20-\x2f\x30-\x39\x3a-\x40\x5b-\x60\x7b-\x7e][\x20-\x7e]+?[\x20-\x2f\x30-\x39\x3a-\x40\x5b-\x60\x7b-\x7e])(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})(?P=var)[^\r\n]+(?P=var)$/s"; reference:md5,ce37b5b473377810bc76e0491533b4e7; classtype:command-and-control; sid:2025136; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_12_06, deployment Perimeter, malware_family njrat, performance_impact Moderate, confidence Medium, signature_severity Major, updated_at 2020_08_19;)