Protect Grub2 with
Plain Password Method
1.)Login
as a root user
su
–
2.)
Backup the existing grub.cfg so if anything goes wrong we can always restore
it.
>>cp
/boot/grub2/grub.cfg /boot/grub2/grub.cfg.orig
To
specify a superuser, add the following lines in the /etc/grub.d/01_users file, where john is
the name of the user designated as the superuser, and johnspassword is the
superuser's password:
cat
<<EOF
set
superusers="john"
password john
johnspassword
EOF
On
BIOS-based machines, issue the following command as root:
>>grub2-mkconfig -o /boot/grub2/grub.cfg
On
UEFI-based machines, issue the following command as root:
>>
grub2-mkconfig -o
/boot/efi/EFI/redhat/grub.cfg
To Use Encrypted
password
Create
the encrypted password using
grub2-mkpasswd-pbkdf2
Enter Password:
Reenter Password:
PBKDF2 hash of your password is grub.pbkdf2.sha512.10000.19074739ED80F115963D984BDCB35AA671C24325755377C3E9B014D862DA6ACC77BC110EED41822800A87FD3700C037320E51E9326188D53247EC0722DDF15FC.C56EC0738911AD86CEA55546139FEBC366A393DF9785A8F44D3E51BF09DB980BAFEF85281CBBC56778D8B19DC94833EA8342F7D73E3A1AA30B205091F1015A85
Now
we can change the entry in the file /etc/grub.d/01_users as follows
cat
<<EOF
set
superusers="john"
password_pbkdf2
john grub.pbkdf2.sha512.10000.19074739ED80F115963D984BDCB35AA671C24325755377C3E9B014D862DA6ACC77BC110EED41822800A87FD3700C037320E51E9326188D53247EC0722DDF15FC.C56EC0738911AD86CEA55546139FEBC366A393DF9785A8F44D3E51BF09DB980BAFEF85281CBBC56778D8B19DC94833EA8342F7D73E3A1AA30B205091F1015A85
EOF