alert tcp $EXTERNAL_NET any -> $HOME_NET [25667,47000] (msg:"ET MALWARE XServer Backdoor Communication Setup Initiate"; flow:established,to_server; flowbits:isset,ET.XServer.cnc; dsize:2; content:"|18 00|"; depth:2; fast_pattern; reference:url,resources.fox-it.com/rs/170-CAK-271/images/201912_Report_Operation_Wocao.pdf; classtype:command-and-control; sid:2029188; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_12_23, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_12_23;)