bash
# Copy public key from Kali VM to clipboard
xclip -sel clip < ~/.ssh/id_rsa.pub # Copies the content of the public key file to the clipboard using xclip command

# Paste copied content into authorized_keys file on target system using echo command and redirection operator >
ssh root@target-ip "echo 'pasted key' >> /root/.ssh/authorized_keys" # Appends the content of the clipboard to the authorized_keys file on the target system using the echo command and redirection operator >>

# This script checks if the SSH configuration file has been configured to allow public key authentication.

# First, we need to store the path of the SSH configuration file in a variable.
ssh_config="/etc/ssh/sshd_config"

# Next, we use the 'grep' command to search for the line that enables public key authentication.
# We use the '-q' flag to suppress any output and the '-F' flag to search for exact matches.
# The 'AllowPublicKeyAuthentication' line should be uncommented and set to 'yes' for it to be enabled.
grep -qF "AllowPublicKeyAuthentication yes" $ssh_config

# We then use the 'if' statement to check the exit status of the previous command.
# If the exit status is 0, it means the line was found and public key authentication is enabled.
# If the exit status is not 0, it means the line was not found and public key authentication is not enabled.
if [ $? -eq 0 ]; then
  echo "Public key authentication is enabled."
else
  echo "Public key authentication is not enabled."
fi

# Finally, we use the 'echo' command to print the appropriate message based on the result of the 'if' statement.

# This script restarts the ssh service using systemctl or service commands

# Use sudo to run the following command as root user
sudo systemctl restart ssh # Corrected the service name to ssh instead of sshd

# The above command restarts the ssh service using systemctl command

# Alternatively, the following command can also be used to restart the ssh service
sudo service ssh restart # Corrected the service name to ssh instead of sshd

# The above command restarts the ssh service using service command

# Connect to target system using SSH and private key (-i option followed by filename as argument)
# Added quotation marks around the file path to prevent errors if there are spaces in the file name
ssh -i "~/.ssh/id_rsa" root@target-ip

# This script connects to a target system as a privileged user and navigates to the .ssh directory of a specific user account.

# The following line uses sudo to run the ssh command as a privileged user.
sudo ssh root@target-ip "cd /home/user/.ssh"

# The -S flag allows the script to read the password from standard input, ensuring it is not visible in the command line.

# The ssh command connects to the target system using the specified IP address and runs the following command within the quotes.

# The "cd" command changes the current directory to the .ssh directory of the affected user account.

# However, this command will not work as intended because it is missing the -t flag, which forces pseudo-terminal allocation. This is necessary for the "cd" command to be executed properly.

# Additionally, the command should specify the user account to be affected, rather than assuming it is the current user. This can be done by adding the username before the "@" symbol in the ssh command.


sudo -S ssh -t root@target-ip "cd /home/user/.ssh"

# This script removes a specific public key from the authorized_keys file on a remote server using the sed command.

# Use sudo to run the following command as root.
sudo -S ssh root@target-ip "sed '/<public_key>/d' /home/user/.ssh/authorized_keys"

# The -S flag allows for the password to be entered through standard input.

# Use ssh to connect to the remote server as root.
ssh root@target-ip

# The root user is specified after the @ symbol.

# Use the sed command to search for and delete the specified public key from the authorized_keys file.
sed '/<public_key>/d' /home/user/.ssh/authorized_keys

# The /d flag tells sed to delete the line containing the specified public key.

# The /home/user/.ssh/authorized_keys file is the location of the authorized_keys file on the remote server.

# The <public_key> placeholder should be replaced with the actual public key that needs to be removed.

# This script restarts the SSH service using systemctl command

# Use sudo to run the command as root user
sudo systemctl restart sshd

# The above command restarts the sshd service, which is responsible for handling SSH connections

# To restart the service, we need to use the restart argument after the service name
# In this case, the service name is sshd

# To ensure the changes take effect, we need to restart the service after making any changes to the configuration file

# This script is a simple and efficient way to restart the SSH service without having to manually type the command every time.