alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Observed Suspicious UA (Absent)"; flow:established,to_server; http.user_agent; content:"Absent"; depth:6; endswith; classtype:bad-unknown; sid:2028571; rev:3; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2019_09_12, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2020_09_17;)