alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT VexTrio Domain in TLS SNI (a .crystalcraft .top)"; flow:established,to_server; tls.sni; bsize:18; content:"a.crystalcraft.top"; fast_pattern; reference:url,blogs.infoblox.com/cyber-threat-intelligence/cybercrime-central-vextrio-operates-massive-criminal-affiliate-program/; classtype:exploit-kit; sid:2050373; rev:2; metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2024_01_23, deployment Perimeter, deprecation_reason Age, performance_impact Low, confidence High, signature_severity Minor, tag Exploit_Kit, tag VexTrio, tag compromised_website, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_26, reviewed_at 2024_03_26;)