alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/ArtraDownloader Checkin"; flow:established,to_server; http.method; content:"POST"; http.header; content:"Content-type|3a 20|application/x-www-form-urlencoded"; http.request_body; content:"BCDEF="; content:"&MNOPQ="; content:"&GHIJ="; content:"&UVWXYZ="; fast_pattern; content:"&st="; reference:md5,7cc0b212d1b8ceb808c250495d83bae4; reference:url,unit42.paloaltonetworks.com/multiple-artradownloader-variants-used-by-bitter-to-target-pakistan; classtype:command-and-control; sid:2026740; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_12_20, deployment Perimeter, malware_family Win32_ArtraDownloader, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_27;)