alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET POLICY Burp Collaborator Domain in TLS SNI"; flow:established,to_server; tls.sni; dotprefix; content:".burpcollaborator.net"; endswith; fast_pattern; classtype:policy-violation; sid:2034506; rev:2; metadata:created_at 2021_11_18, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_11_18;)