alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET INFO ATF file in HTTP Flowbit Set"; flow:from_server,established; file_data; content:"|41 54 46|"; within:3; flowbits:set,ET.atf.in.http; flowbits:noalert; classtype:not-suspicious; sid:2023714; rev:2; metadata:attack_target Client_Endpoint, created_at 2017_01_10, deployment Perimeter, confidence High, signature_severity Informational, updated_at 2019_07_26;)