The NGINX service account must be configured to not have admin group access.

A mechanism to detect and prevent unauthorized communication flow must be configured or provided as part of the system design. If information flow is not enforced based on approved authorizations, the system may become compromised. Information flow control regulates where information is allowed to travel within a system and between interconnected systems. The flow of all system information must be monitored and controlled so it does not introduce any unacceptable risk to the systems or data.

Application-specific examples of enforcement occur in systems that employ rule sets or establish configuration settings that restrict information system services, or message-filtering capability based on message content (e.g., implementing key word searches or using document characteristics).

Applications providing information flow control must be able to enforce approved authorizations for controlling the flow of information within the system in accordance with applicable policy.

Determine the path to NGINX config file(s):

nginx -qT | grep "# configuration" # configuration file /etc/nginx/nginx.conf:

Note: The default NGINX configuration is "/etc/nginx/nginx.conf", though various files may also be included.

Identify the NGINX runtime user:

grep -E '^\s*user\s+' /etc/nginx/nginx.conf

Expected output (example):

user nginx;

Ensure the user is not in a privileged group:

id nginx

Expected output:

uid=980(nginx) gid=979(nginx) groups=979(nginx)

The user should not be a member of sudo, wheel, admin, or similar elevated groups.

If the NGINX runtime user is a member of an elevated group, this is a finding.

Remove the user from privileged groups:

sudo gpasswd -d nginx sudo
sudo gpasswd -d nginx wheel
sudo gpasswd -d nginx admin