alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MSIL.BackNet Checkin"; flow:established,to_server; http.method; content:"POST"; http.request_body; content:"data=%7B%22host_key%22%3A%22"; depth:28; http.header_names; content:!"Referer"; content:!"User-Agent"; reference:md5,aebb382b54e1521ad1309f66d29a1d1c; classtype:command-and-control; sid:2026572; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_11_02, deployment Perimeter, malware_family Stealer, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_27;)