alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE DNS Changer HTTP Post Checkin"; flow:established,to_server; http.method; content:"POST"; nocase; http.header_names; content:!"|0d 0a|User-Agent|0d 0a|"; http.request_body; content:"x="; startswith; pcre:"/^x=[0-9a-zA-Z]{50}/"; classtype:command-and-control; sid:2008263; rev:14; metadata:created_at 2010_07_30, signature_severity Major, updated_at 2024_02_09;)