alert tcp any [21,22,23,25,53,80,443,8080] -> any !3389 (msg:"ET POLICY Tunneled RDP Handshake"; flow:established; content:"|c0 00|Duca"; depth:250; content:"rdpdr"; content:"cliprdr"; reference:url,www.fireeye.com/blog/threat-research/2019/01/bypassing-network-restrictions-through-rdp-tunneling.html; classtype:bad-unknown; sid:2027193; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_04_11, deployment Perimeter, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)