alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Windows Update/Microsoft FP Flowbit M1"; flow:established,to_server; flowbits:set,ET.INFO.WindowsUpdate; flowbits:noalert; http.host; dotprefix; content:".windowsupdate.com"; endswith; reference:url,learn.microsoft.com/en-us/windows-server/administration/windows-server-update-services/deploy/2-configure-wsus#211-configure-your-firewall-to-allow-your-first-wsus-server-to-connect-to-microsoft-domains-on-the-internet; classtype:not-suspicious; sid:2023818; rev:5; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state plaintext, created_at 2017_02_01, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_01_16;)