alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Likely Malicious Windows SCT Download MSXMLHTTP M3"; flow:established,from_server; flowbits:isset,et.IE7.NoRef.NoCookie; http.header; content:"Content-Disposition|3a 20|"; nocase; content:".sct"; nocase; fast_pattern; pcre:"/^Content-Disposition\x3a[^\r\n]*\.sct[\x22\x27\s\r\n]/mi"; classtype:trojan-activity; sid:2024552; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_08_15, deployment Perimeter, malware_family PowerShell, confidence Medium, signature_severity Major, tag PowerShell_Downloader, updated_at 2020_10_09;)