alert dns $HOME_NET any -> any any (msg:"ET INFO Observed DNS Query to *.ngrok Domain (ngrok .dev)"; dns.query; dotprefix; content:".ngrok.dev"; nocase; endswith; reference:url,ngrok.com/blog-post/new-ngrok-domains; classtype:misc-activity; sid:2049051; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_11_02, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_11_02, reviewed_at 2024_05_03; target:src_ip;)