alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Possible Machine GUID Observed in HTTP POST"; flow:established,to_server; http.method; content:"POST"; http.request_body; content:"&machineId="; fast_pattern; pcre:"/^(?:[a-z0-9]{8})\x2d(?:[a-z0-9]{4})\x2d(?:[a-z0-9]{4})\x2d(?:[a-z0-9]{4})\x2d(?:[a-z0-9]{12})/R"; classtype:misc-activity; sid:2054968; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2024_08_06, deployment Perimeter, deployment SSLDecrypt, confidence Low, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_08_07;)