Check: GEN005200
Title
X displays must not be exported to the world. (Cat III impact)
Discussion
Open X displays allow an attacker to capture keystrokes and to execute commands remotely. Many users have their X Server set to xhost +, permitting access to the X Server by anyone, from anywhere.
Check Content
If X Windows is not used on the system, this is not applicable. Check the output of the xhost command from an X terminal. Procedure: $ xhost If the output reports access control is enabled (and possibly lists the hosts that can receive X Window logins), this is not a finding. If the xhost command returns a line indicating access control is disabled, this is a finding.
Fix Text
If using an xhost-type authentication the xhost - command can be used to remove current trusted hosts and then selectively allow only trusted hosts to connect with xhost + commands. A cryptographically secure authentication, such as provided by the xauth program, is always preferred. Refer to your X11 server's documentation for further security information.
Additional Identifiers
Rule ID:
Vulnerability ID: V-4697
Group Title:
Expert Comments
CCIs
| Number | Definition |
|---|---|
| CCI-000225 |
The organization employs the concept of least privilege, allowing only authorized accesses for users (and processes acting on behalf of users) which are necessary to accomplish assigned tasks in accordance with organizational missions and business functions. |
Controls
| Number | Title |
|---|---|
| AC-6 |
Least Privilege |