alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET INFO Suspicious File Extension Inbound (.phonk)"; flow:established,to_client; http.response_header; header_lowercase; content:"content-disposition|3a 20|attachment|3b 20|filename|3d|"; startswith; content:".phonk"; fast_pattern; endswith; threshold:type limit, seconds 120, count 1, track by_src; reference:md5,cc101b016deadd7d54994e282e89a2ec; reference:url,tria.ge/221206-2fvxqadb5v/behavioral1; classtype:misc-activity; sid:2042944; rev:2; metadata:attack_target Client_Endpoint, created_at 2022_12_14, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_26, reviewed_at 2025_10_24;)