alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Backdoor Lanfiltrator Checkin"; flow:established,to_server; http.uri; content:"/ralog.cgi?action="; nocase; fast_pattern; content:"&ip="; nocase; content:"&servertype="; nocase; distance:0; http.header_names; content:!"Referer|0d 0a|"; reference:url,research.sunbelt-software.com/threatdisplay.aspx?name=Backdoor.Win32.LanFiltrator.3b&threatid=51642; classtype:command-and-control; sid:2009078; rev:8; metadata:created_at 2010_07_30, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_13;)