To restrict root logins on serial ports, ensure lines of this form do not appear in '/etc/securetty': ttyS0 ttyS1 [no/yes] Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account. oval:org.secpod.oval:def:31255 oval:org.secpod.oval:def:30532 SCAP Repo OVAL Definition 2015-11-13