AlmaLinux OS 9 system accounts must not have an interactive login shell.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-269300	SRG-OS-000480-GPOS-00227	ALMA-09-024990	SV-269300r1050182_rule	2025-02-20	1

Description
Ensuring shells are not given to system accounts upon login makes it more difficult for attackers to make use of system accounts.

ℹ️ Check
Verify that system accounts must not have an interactive login shell with the following command: $ awk -F: '($3<1000){print $1 ":" $3 ":" $7}' /etc/passwd root:0:/bin/bash bin:1:/sbin/nologin daemon:2:/sbin/nologin adm:3:/sbin/nologin lp:4:/sbin/nologin sync:5:/bin/sync shutdown:6:/sbin/shutdown halt:7:/sbin/halt mail:8:/sbin/nologin operator:11:/sbin/nologin games:12:/sbin/nologin ftp:14:/sbin/nologin systemd-coredump:999:/sbin/nologin dbus:81:/sbin/nologin polkitd:998:/sbin/nologin tss:59:/sbin/nologin sssd:997:/sbin/nologin unbound:996:/sbin/nologin fapolicyd:995:/sbin/nologin postfix:89:/sbin/nologin sshd:74:/sbin/nologin chrony:994:/sbin/nologin systemd-oom:989:/usr/sbin/nologin Identify the system accounts from this listing that do not have a nologin shell. If any system account (other than the root account) has a login shell and it is not documented with the information system security officer (ISSO), this is a finding.

ℹ️ Check

Verify that system accounts must not have an interactive login shell with the following command: $ awk -F: '($3<1000){print $1 ":" $3 ":" $7}' /etc/passwd root:0:/bin/bash bin:1:/sbin/nologin daemon:2:/sbin/nologin adm:3:/sbin/nologin lp:4:/sbin/nologin sync:5:/bin/sync shutdown:6:/sbin/shutdown halt:7:/sbin/halt mail:8:/sbin/nologin operator:11:/sbin/nologin games:12:/sbin/nologin ftp:14:/sbin/nologin systemd-coredump:999:/sbin/nologin dbus:81:/sbin/nologin polkitd:998:/sbin/nologin tss:59:/sbin/nologin sssd:997:/sbin/nologin unbound:996:/sbin/nologin fapolicyd:995:/sbin/nologin postfix:89:/sbin/nologin sshd:74:/sbin/nologin chrony:994:/sbin/nologin systemd-oom:989:/usr/sbin/nologin Identify the system accounts from this listing that do not have a nologin shell. If any system account (other than the root account) has a login shell and it is not documented with the information system security officer (ISSO), this is a finding.

✔️ Fix
Configure AlmaLinux OS 9 so that all noninteractive accounts on the system do not have an interactive shell assigned to them. If the system account needs a shell assigned for mission operations, document the need with the ISSO. Run the following command to disable the interactive shell for a specific noninteractive user account, replacing <user> with the user that has a login shell. $ usermod --shell /sbin/nologin <user> Do not perform the steps in this section on the root account. Doing so will cause the system to become inaccessible.

✔️ Fix

Configure AlmaLinux OS 9 so that all noninteractive accounts on the system do not have an interactive shell assigned to them. If the system account needs a shell assigned for mission operations, document the need with the ISSO. Run the following command to disable the interactive shell for a specific noninteractive user account, replacing <user> with the user that has a login shell. $ usermod --shell /sbin/nologin <user> Do not perform the steps in this section on the root account. Doing so will cause the system to become inaccessible.