alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Agent.XST/UP007 Keepalive 2"; flow:established,to_server; threshold:type limit, count 1, seconds 60, track by_src; http.method; content:"POST"; http.uri; content:".asp"; http.header; content:"Content-Length|3a 20|5|0d 0a|"; fast_pattern; http.request_body; content:"READY"; depth:5; http.content_type; content:"text/html"; bsize:9; http.header_names; content:!"Referer|0d 0a|"; content:!"Accept|0d 0a|"; reference:url,citizenlab.org/2016/04/between-hong-kong-and-burma; classtype:trojan-activity; sid:2022750; rev:4; metadata:created_at 2016_04_20, malware_family Win32_Agent_XST_UP007, signature_severity Major, updated_at 2020_10_06;)