TMA-BIND-2.2

Give the BIND User Account an Invalid Shell

MediumLevel 1Automatedbind

Description

The BIND user account, named by default, must not be used as a regular login account, and should be assigned an invalid or nologin shell to ensure that the account cannot be used to login. The audit reads /etc/passwd and requires the named (or bind) account shell to be /sbin/nologin, /bin/false or /dev/null.

How it is checked

Audit method: Shell command

shell

bad=0; n=0
for u in named bind; do
  s=$(awk -F: -v u=$u '$1==u{print $7}' /etc/passwd) || exit 1
  [ -n "$s" ] || continue; n=1
  case "$s" in /sbin/nologin|/usr/sbin/nologin|/bin/false|/usr/bin/false|/dev/null) ;; *) echo "$u shell $s"; bad=1 ;; esac
done
[ "$n" -eq 1 ] || { echo 'no named/bind account'; exit 1; }
[ "$bad" -eq 0 ] && echo compliant

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Change the named account to use the nologin shell as shown: # chsh -s /sbin/nologin named

Properties

Operating systems: Any
Tags: binddnspermissions
Reference: CIS ISC BIND DNS Server 9.11 Benchmark v1.0.0 - 2.2 Give the BIND User Account an Invalid Shell

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target bind