What is Accesible XDMCP

Accesible XDMCP

Vulnerable computer systems and applications:

Computers, service stations with UNIX-like type operating system.


On computers running a UNIX-like operating system (such as Linux), a software package “X Display Manager,” is used to display images. A protocol called “X Display Manager Control Service” (XDMCP), if it is accessible from the Internet, typically forms two types of responses to queries: “Willing” (the customer will be provided with a service from the server) and “Unwilling” (service to the customer will not be provided).

The XDMCP protocol, available from the Internet, can be used for service disruption attacks. It is worth mentioning that attackers can exploit the device when it forms both “Willing” and “Unwilling” responses.


  • Limit access to the UDP protocol 177 port from an external network.