alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT Possible Styx EK SilverLight Payload"; flow:established,to_server; urilen:19; http.uri; content:"/1"; depth:2; fast_pattern; pcre:"/^[a-z0-9]{13}\.[a-z]{3}$/R"; http.header_names; content:!"Referer|0d 0a|"; content:!"User-Agent|0d 0a|"; classtype:exploit-kit; sid:2017731; rev:6; metadata:created_at 2013_11_20, deprecation_reason Performance, performance_impact Significant, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_05_01;)