alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Oyster Backdoor Domain (daringdatadaredevils .com) in TLS SNI"; flow:established,to_server; tls.sni; dotprefix; content:".daringdatadaredevils.com"; endswith; fast_pattern; reference:url,malpedia.caad.fkie.fraunhofer.de/details/win.broomstick; reference:url,www.cyberproof.com/blog/oyster-backdoor-the-malvertising-menace-masquerading-as-popular-tools/; reference:url,www.catonetworks.com/blog/cato-ctrl-oyster-malware-campaign/; classtype:domain-c2; sid:2064614; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2025_09_12, deployment Perimeter, malware_family Oyster_Backdoor, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_09_12, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1189, mitre_technique_name Drive_by_Compromise;)