alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE FrigidBackdoor Checkin"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/api/external/machines/me"; http.user_agent; content:"Go-http-client"; http.request_body; content:"|22|machine|5f|id|22 3a|"; fast_pattern; content:"|22|hostname|22 3a|"; distance:0; content:"|22|username|22 3a|"; distance:0; content:"|22|os|22 3a|"; distance:0; content:"|22|platform|22 3a|"; distance:0; content:"|22|arch|22 3a|"; distance:0; reference:url,moonlock.com/macc-stealer-macsync-backdoor; classtype:trojan-activity; sid:2064774; rev:2; metadata:affected_product Mac_OSX, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2025_09_17, deployment Perimeter, confidence High, signature_severity Major, tag Stealer, tag Backdoor, tag Description_Generated_By_Proofpoint_Nexus, tag FrigidStealer, tag FrigidBackdoor, updated_at 2025_10_08, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)