alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Unknown Botnet Checkin"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php"; pcre:"/\.php$/"; http.content_type; content:"application/x-www-form-urlencoded"; startswith; http.header_names; content:!"|0d 0a|Referer|0d 0a|"; http.request_body; content:"data="; startswith; nocase; content:"ew0KCSJhZGRyZXNzIiA6"; fast_pattern; nocase; distance:0; classtype:command-and-control; sid:2022891; rev:3; metadata:created_at 2016_06_13, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_02_27;)