alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Dyre CnC Checkin"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"_W"; fast_pattern; pcre:"/_W\d+\.[A-F0-9]+\/\d+\/[^\x2f]+\/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\/$/"; http.header_names; content:!"Accept"; content:!"Referer|0d 0a|"; content:"|0d 0a|User-Agent|0d 0a|"; startswith; reference:md5,3e215dfa84c271bb431b3de2e5da016a; classtype:command-and-control; sid:2021556; rev:4; metadata:created_at 2015_07_31, performance_impact Significant, signature_severity Major, updated_at 2024_04_22;)