alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET POLICY [401TRG] DropBox Access via API (Certificate)"; flow:established,from_server; tls.cert_subject; content:"CN=content.dropboxapi.com"; reference:url,github.com/dropbox/dbxcli; classtype:policy-violation; sid:2030703; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_08_19, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_19;)