This detection rule is designed to identify potentially malicious VNC (Virtual Network Computing) traffic directed to the Internet. VNC is primarily utilized by system administrators for remote maintenance but can be abused by threat actors to gain unauthorized access to systems. The rule checks for network events where VNC traffic, which typically runs on TCP ports 5800 to 5810, is being sent from internal IP addresses to external IP addresses. Any instance of this behavior raises a flag suggesting that the VNC service may be improperly exposed to the Internet, highlighting a potential security risk. The rule includes filtering mechanisms to exclude legitimate internal usage patterns and provides guidance for investigation and false positive management, ensuring that genuine administrative activities are not incorrectly categorized as threats. Additionally, it emphasizes the importance of following up on alerts with tactical and strategic responses to mitigate any identified risks.