alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Bitter RAT TCP CnC Beacon"; flow:established,from_server; content:"BITTER1234"; depth:10; reference:url,blogs.forcepoint.com/security-labs/bitter-targeted-attack-against-pakistan; reference:md5,6e855944d171a3acbb64635dbe7a9c62; classtype:command-and-control; sid:2023399; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2016_10_24, deployment Perimeter, malware_family Bitter_implant, confidence High, signature_severity Major, tag c2, updated_at 2019_07_26, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)