alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Observed trycloudflare .com Domain in TLS SNI"; flow:established,to_server; tls.sni; dotprefix; content:".trycloudflare.com"; endswith; fast_pattern; reference:url,try.cloudflare.com/; reference:url,www.bleepingcomputer.com/news/security/hackers-abuse-free-trycloudflare-to-deliver-remote-access-malware/; classtype:misc-activity; sid:2060250; rev:1; metadata:affected_product Any, attack_target Client_and_Server, tls_state TLSEncrypt, created_at 2025_02_21, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2025_02_21, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1665, mitre_technique_name Hide_Infrastructure;)