alert tcp $HOME_NET any -> $EXTERNAL_NET 4000 (msg:"ET MALWARE Nazar Implant - Sending Ping Response to CnC"; flow:established,to_server; dsize:9; content:"|31 30 31 3b 30 30 30 30 3b|"; fast_pattern; reference:url,research.checkpoint.com/2020/nazar-spirits-of-the-past/; classtype:command-and-control; sid:2030104; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2020_05_05, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag NazarAPT, updated_at 2020_05_05;)