Title

Reserved UIDs 0-99 must only be used by system accounts. (Cat II impact)

Discussion

If a user is assigned a UID that is in the reserved range, even if it is not presently in use, security exposures can arise if a subsequently installed application uses the same UID.

Check Content

The root role is required. Check that reserved UIDs are not assigned to non-system users. Determine the OS version you are currently securing: # uname –v For Solaris 11, 11.1, 11.2, and 11.3: # logins -so | awk -F: '{ print $1 }' | while read user; do found=0 for tUser in root daemon bin sys adm dladm netadm netcfg \ ftp dhcpserv sshd smmsp gdm zfssnap aiuser \ polkitd ikeuser lp openldap webservd unknown \ uucp nuucp upnp xvm mysql postgres svctag \ pkg5srv nobody noaccess nobody4; do if [ ${user} = ${tUser} ]; then found=1 fi done if [ $found -eq 0 ]; then echo "Invalid User with Reserved UID: ${user}" fi done If output is produced without justification and documentation in accordance with site policy, this is a finding. For Solaris 11.4 or newer: # logins -so | awk -F: '{ print $1 }' | while read user; do found=0 for tUser in root daemon bin sys adm dladm netadm \ netcfg dhcpserv sshd smmsp gdm zfssnap aiuser _polkitd \ ikeuser lp openldap webservd unknown \ uucp nuucp upnp xvm mysql postgres svctag \ pkg5srv nobody noaccess nobody4 _ntp; do if [ ${user} = ${tUser} ]; then found=1 fi done if [ $found -eq 0 ]; then echo "Invalid User with Reserved UID: ${user}" fi done If output is produced without justification and documentation in accordance with site policy, this is a finding.

Fix Text

The root role is required. Correct or justify any items discovered in the Check step. Determine if there are any accounts using these reserved UIDs, and work with their owners to determine the best course of action in accordance with site policy. This may require deleting users or changing UIDs for users.

Additional Identifiers

Rule ID: SV-216429r809489_rule

Vulnerability ID: V-216429

Group Title: SRG-OS-000480

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.