alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET WEB_SERVER FOX-SRT - Backdoor - CryptoPHP Shell C2 POST (fsockopen)"; flow:established,to_server; threshold:type limit, track by_src, count 1, seconds 600; content:"serverKey="; fast_pattern; content:"data="; content:"key="; http.method; content:"POST"; http.connection; content:"close"; depth:5; endswith; http.content_type; content:"application/x-www-form-urlencoded"; depth:33; http.header_names; content:!"Referer|0d 0a|"; content:!"User-Agent"; content:!"Cookie|0d 0a|"; reference:url,blog.fox-it.com/2014/11/18/cryptophp-analysis-of-a-hidden-threat-inside-popular-content-management-systems/; classtype:command-and-control; sid:2019749; rev:4; metadata:created_at 2014_11_20, signature_severity Major, updated_at 2020_11_03;)