alert tcp $HOME_NET any -> $EXTERNAL_NET 1024: (msg:"ET MALWARE APT/Bitter CnC Exfiltration via TCP"; flow:established,to_server; stream_size:client,<,200; content:"|00|"; offset:1; depth:1; content:"|00|"; distance:1; within:1; pcre:"/(?:([a-zA-Z0-9]\0){10,})/R"; content:"XXXXXXXXX"; fast_pattern; endswith; reference:md5,71e1cfb5e5a515cea2c3537b78325abf; reference:url,twitter.com/RedDrip7/status/1536989979229835265; classtype:command-and-control; sid:2036996; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2022_06_15, deployment Perimeter, malware_family Bitter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_04_04, reviewed_at 2024_01_02;)