alert http [$HOME_NET,$SMTP_SERVERS] any -> any any (msg:"ET MALWARE OWAReaper C2 File Exfiltration (ews_extensions_debug.json)"; flow:established,to_server; http.uri; content:"/assets/v1_"; fast_pattern; pcre:"/^[A-Za-z0-9\x2d\x5f]+$/R"; http.request_body; strip_whitespace; content:"|22|InstalledExtensionsCollection|22 3a|"; content:"|22|ResponseMessages|22 3a|"; http.method; content:"POST"; classtype:trojan-activity; sid:2071333; rev:1; metadata:attack_target Client_Endpoint, created_at 2026_07_28, deployment Perimeter, malware_family OWAReaper, confidence High, signature_severity Major, tag c2, updated_at 2026_07_28, former_sid 2868081, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)