alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE APT36 User-Agent Observed (FitnessTracker/)"; flow:established,to_server; http.user_agent; content:"FitnessTracker/"; startswith; fast_pattern; pcre:"/^\d{1,2}\x2e\d{1,5}$/R"; classtype:trojan-activity; sid:2068974; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_04_24, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Major, tag APT36, updated_at 2026_04_24, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)