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Linux tutorial: Disable login as “root” user via SSH as a security measure

 4 years ago
source link: https://github.com/VeliovGroup/ostrio/blob/master/tutorials/linux/security/disable-ssh-root.md
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Disable SSH login for root user

Why?

  • Most of the automatic brute-force software starts with attacking SSH service on 22 port and try to match a password for the root user
  • root user is not the only user under risk, brute-force software has abundant dictionaries of most common used user-names, so it's a good idea to create a user with some random-gibberish name, like: QBHZEEQXT

Before you go:

Edit /etc/ssh/sshd_config file: 

# nano /etc/ssh/sshd_config

# Find line starting with "PermitRootLogin"
# change "yes" to "no":
PermitRootLogin no

# Save file with: "ctrl + o" combination
# Close file with: "ctrl + x" combination

Add extra security layer, with limiting login only to a single user ( optional ): 

# nano /etc/ssh/sshd_config

# Add new line, where username
# is a name of ONLY allowed to login
# over SSH user:
AllowUsers username

# Save file with: "ctrl + o" combination
# Close file with: "ctrl + x" combination

Restart SSH service:

service sshd restart

Further reading:


report

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