打6元不朽情缘第四滴血图

書名： Practical Linux Security Cookbook
作者名： Tajinder Kalsi
本章字?jǐn)?shù)： 615字
更新時(shí)間： 2021-07-16 11:05:29

Making use of sudoers – configuring sudo access

Whenever the system administrator wants to provide trusted users administrative access to the system without sharing the password of the root user, they can do so using the sudo mechanism.

Once the user is given access using the sudo mechanism, they can execute any administrative command by preceding it with sudo. Then, the user will be asked to enter their own password. After this, the administrative command will be executed in the same way as run by the root user.

Getting ready

As the file for the configuration is predefined and the commands used are inbuilt, nothing extra needs to be configured before starting these steps.

How to do it…

We will first create a normal account and then give it sudo access. Once done, we will be able to use the sudo command from the new account and then execute the administrative commands. Follow the steps given to configure the sudo access. Firstly, use the root account to login to the system. Then, create a user account using the useradd command, as shown in the following figure:

Replace USERNAME with any name of your choice in the preceding command.
Now, using the passwd command, set a password for the new user account.
Edit the /etc/sudoers file by running visudo. The policies applied when using the sudo command are defined by the /etc/sudoers file.
Once the file is open in the editor, search for the following lines, which allow sudo access to the users in the test group:
We can enable the given configuration by deleting the comment character (#) at the beginning of the second line. Once the changes are made, save the file and exit from the editor. Now, using the usermod command, add the previously created user to the test group.
We need to check whether the configuration shown in the preceding screenshot allows the new user account to run commands using sudo.
To switch to the newly created user account, use the su option.
Now, use the groups command to confirm the presence of the user account in the test group.

Finally, run the whoami command with sudo from the new account. As we have executed a command that uses sudo for the first time, using this new user account, the default banner message will be displayed for the sudo command. The screen will also ask for the user account password to be entered.
The last line of the preceding output is the username returned by the whoami command. If sudo is configured correctly, this value will be root.

You have successfully configured a user with sudo access. You can now log in to this user account and use sudo to run commands the same way as you would from the root user.

How it works…

When we create a new account, it does not have permission to run administrator commands. However, after editing the /etc/sudoers file and making an appropriate entry to grant sudo access to the new user account, we can start using the new user account to run all the administrator commands.

There's more…

Here is an extra measure that you can take to ensure total security.

Vulnerability assessment

A vulnerability assessment is the process of auditing our network and system security through which we can know about the confidentiality, integrity, and availability of our network. The first phase in the vulnerability assessment is reconnaissance, and this further leads to the phase of system readiness in which we mainly check for all known vulnerabilities in the target. The next phase is reporting, where we group all the vulnerabilities found into categories of low, medium, and high risk.

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