alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Observed Suspicious UA (Hello, World)"; flow:established,to_server; http.user_agent; content:"Hello, World"; startswith; endswith; classtype:bad-unknown; sid:2027503; rev:4; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2019_06_21, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2024_04_13;)