alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE [PTsecurity] Bitter RAT C2 Response"; flow:established,to_client; stream_size:client,=,1; stream_size:server,=,12; dsize:11; content:"|0b 00 d2 0b 00 00|"; offset:5; depth:6; reference:md5,fc516905e3237f1aa03a38a0dde84b52; classtype:command-and-control; sid:2026826; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_01_21, deployment Perimeter, malware_family BitterRAT, performance_impact Low, confidence Medium, signature_severity Major, tag RAT, updated_at 2019_07_26;)