Title

Device files and directories must only be writable by users with a system account or as configured by the vendor. (Cat II impact)

Discussion

System device files in writable directories could be modified, removed, or used by an unprivileged user to control system hardware.

Check Content

Find all device files existing anywhere on the system. Procedure: # find / -type b -print > devicelist # find / -type c -print >> devicelist Check the permissions on the directories above subdirectories containing device files. The following list of device files are intended to be world-writable and if present are not a finding. /dev/arp /dev/conslog /dev/crypto /dev/dtrace/dtrace /dev/dtrace/helper /dev/dtrace/provider/fasttrap /dev/fd/* /dev/kstat /dev/null /dev/poll /dev/pool /dev/ptmx /dev/sad/user /dev/tcp /dev/tcp6 /dev/ticlts /dev/ticots /dev/ticotsord /dev/tty /dev/udp /dev/udp6 /dev/zero /dev/zfs If any device file or their parent directory is world-writable and it is not intended to be world-writable, this is a finding.

Fix Text

Remove the world-writable permission from the device file(s). Procedure: # chmod o-w <device file> Document all changes.

Additional Identifiers

Rule ID: SV-227699r603266_rule

Vulnerability ID: V-227699

Group Title: SRG-OS-000480

Expert Comments

CCIs tied to check.

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