Rule History

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET ATTACK_RESPONSE Observed AsyncRat Installer Inbound"; flow:established,to_client; http.content_type; content:"application/x-msdownload"; http.header; content:"content|2d|disposition|3a 20|attachment|3b 20|filename|3d|asyncclient|2e|exe"; nocase; fast_pattern; content:"cloudflare.com"; nocase; http.response_body; content:"|4D 5A|"; startswith; classtype:trojan-activity; sid:2064060; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2025_08_20, deployment Perimeter, deployment SSLDecrypt, malware_family AsyncRAT, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_08_20, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1105, mitre_technique_name Ingress_Tool_Transfer; target:dest_ip;)