CISA warns of the "BlueKeep" vulnerability affecting several Microsoft Windows operating systems. This vulnerability allows attackers to gain control of vulnerable systems remotely. BlueKeep resides within the Remote Desktop Protocol (RDP) and enables remote code execution. Attackers can send specially crafted packets to vulnerable systems with RDP enabled. Successful exploitation allows for actions like installing programs and altering data. BlueKeep is considered "wormable," meaning it could spread rapidly like the WannaCry malware. CISA has confirmed Windows 2000's vulnerability to BlueKeep. Users should apply the available security patches released by Microsoft. Alternative mitigations include upgrading aging operating systems and disabling unnecessary services. Enabling Network Level Authentication also protects against BlueKeep in specific Windows versions. Blocking TCP port 3389 at the firewall can prevent external exploitation. CISA encourages users and administrators to review the provided Microsoft resources for detailed guidance.