alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Possible Sharik/Smoke Loader Microsoft Connectivity check"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/kb/"; depth:4; fast_pattern; pcre:"/^\d{4,8}$/R"; http.user_agent; content:!"Microsoft Outlook"; http.header_names; content:!"Referer"; content:"User-Agent"; content:!"Accept"; reference:md5,7e604b9e059d054d58c91330d4d88c62; classtype:trojan-activity; sid:2025120; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_12_05, deployment Perimeter, confidence Medium, signature_severity Major, tag Smoke_Loader, updated_at 2020_08_24;)