alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Sofacy Request Outbound"; flow:established,to_server; http.uri; content:"/?"; content:"&ai="; fast_pattern; content:!"&adurl="; pcre:"/^\/[a-z]+?\/\?(?:[a-z]+?=[A-Za-z0-9\x5f\x2d]+&){1,}ai=[^&]{5}(?:[A-Za-z0-9\x5f\x2d]{4})*(?:[A-Za-z0-9\x5f\x2d]{2}==|[A-Za-z0-9\x5f\x2d]{3}=|[A-Za-z0-9\x5f\x2d]{4})(?:&|$)/"; http.user_agent; content:"Windows NT"; http.header_names; content:!"Referer"; classtype:targeted-activity; sid:2019545; rev:1238; metadata:created_at 2014_10_29, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_09;)