OL 9 must disable the use of user namespaces.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-271727 | SRG-OS-000480-GPOS-00227 | OL09-00-002370 | SV-271727r1091893_rule | 2026-02-17 | 1 |
Description
User namespaces are used primarily for Linux containers. The value "0" disallows the use of user namespaces.
ℹ️ Check
Note: User namespaces are used primarily for Linux containers. If containers are in use, this requirement is Not Applicable.
Verify that OL 9 disables the use of user namespaces with the following commands:
$ sysctl user.max_user_namespaces
user.max_user_namespaces = 0
If the returned line does not have a value of "0", or a line is not returned, this is a finding.
✔️ Fix
Configure OL 9 to disable the use of user namespaces by adding the following line to a file, in the "/etc/sysctl.d" directory:
Note: User namespaces are used primarily for Linux containers. If containers are in use, this requirement is Not Applicable.
user.max_user_namespaces = 0
The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command:
$ sudo sysctl --system