1.8.4 Ensure XDMCP is not enabled

Information

X Display Manager Control Protocol (XDMCP) is designed to provide authenticated access to display management services for remote displays

XDMCP is inherently insecure.

- XDMCP is not a ciphered protocol. This may allow an attacker to capture keystrokes entered by a user
- XDMCP is vulnerable to man-in-the-middle attacks. This may allow an attacker to steal the credentials of legitimate users by impersonating the XDMCP server.

Solution

Edit the file /etc/gdm/custom.conf and remove the line

Enable=true

See Also

https://workbench.cisecurity.org/files/3742

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, 800-53|CM-7, CSCv7|9.2

Plugin: Unix

Control ID: 0b22dc32fd59c3b93a52d161f3b37f15bcf20f258b4bd184cf0b38c33df818e5