The operating system must prevent remote devices that have established a non-remote connection with the system from communicating outside of the communication path with resources in external networks.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-216129 | SRG-OS-000480 | SOL-11.1-040490 | SV-216129r959010_rule | 2026-02-19 | 3 |
Description
This control enhancement is implemented within the remote device (e.g., notebook/laptop computer) via configuration settings not configurable by the user of the device. An example of a non-remote communications path from a remote device is a virtual private network. When a non-remote connection is established using a virtual private network, the configuration settings prevent split-tunneling. Split-tunneling might otherwise be used by remote users to communicate with the information system as an extension of the system and to communicate with local resources, such as a printer or file server. The remote device, when connected by a non-remote connection, becomes an extension of the information system allowing dual communications paths, such as split-tunneling, in effect allowing unauthorized external connections into the system. This is a split-tunneling requirement that can be controlled via the operating system by disabling interfaces.
ℹ️ Check
Determine if the "RestrictOutbound" profile is configured properly:
# profiles -p RestrictOutbound info
If the output is not:
name=RestrictOutbound
desc=Restrict Outbound Connections
limitpriv=zone,!net_access
this is a finding.
For users who are not allowed external network access, determine if a user is configured with the "RestrictOutbound" profile.
# profiles -l [username]
If the output does not include:
[username]:
RestrictOutbound
this is a finding.
✔️ Fix
The root Role is required.
Remove net_access privilege from users who may be accessing the systems externally.
1. Create an RBAC Profile with net_access restriction
# profiles -p RestrictOutbound
profiles:RestrictOutbound> set desc="Restrict Outbound Connections"
profiles:RestrictOutbound> set limitpriv=zone,!net_access
profiles:RestrictOutbound> exit
2. Assign the RBAC Profile to a user
# usermod -P +RestrictOutbound [username]
This prevents the user from initiating any outbound network connections.