alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Observed WindowsPowerShell/5.1 User Agent Usage"; flow:established,to_server; http.user_agent; content:"windowspowershell/5.1"; nocase; fast_pattern; classtype:misc-activity; sid:2071744; rev:1; metadata:attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_08_22, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Informational, updated_at 2026_08_22;)