Part 10: Set file permissions

Remove SetGID Permissions From System Files
Make the following manual changes.
chmod g-s /usr/bin/mail
chmod g-s /usr/bin/mailx
chmod g-s /usr/bin/write
chmod g-s /usr/bin/netstat
chmod g-s /usr/bin/nfsstat
chmod g-s /usr/bin/ipcs

chmod g-s /usr/sbin/arp
chmod g-s /usr/sbin/dmesg
chmod g-s /usr/sbin/prtconf
chmod g-s /usr/sbin/swap
chmod g-s /usr/sbin/sysdef
chmod g-s /usr/sbin/wall


chmod g-s /usr/lib/fs/ufs/ufsdump
chmod g-s /usr/lib/fs/ufs/ufsrestore

Prohibit the Execution of SetUID Programs
To prevent execution of setuid programs, use the nosuid option in /etc/vfstab.

The /usr file system contains some setuid executables essential to system operation. It is recommended it be mounted read-only instead of using the nosuid option.

/proc - /proc proc - no -
fd - /dev/fd fd - no -
swap - /tmp tmpfs - yes -
/dev/dsk/c0t3d0s1 - - swap - no -
/dev/dsk/c0t3d0s0 /dev/rdsk/c0t3d0s0 / ufs 1 no remount,nosuid
/dev/dsk/c0t3d0s4 /dev/rdsk/c0t3d0s4 /usr ufs 1 no ro
/dev/dsk/c0t3d0s5 /dev/rdsk/c0t3d0s5 /var ufs 1 no nosuid

Click here for the rest of this 12-part tip.