alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Observed certreq User-Agent (NDES client)"; flow:established,to_server; http.user_agent; content:"Mozilla/4.0 (compatible|3b 20|Win32|3b 20|NDES client"; startswith; reference:url,dtm.uk/certreq; classtype:bad-unknown; sid:2043274; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_01_11, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_01_11;)