Category: SECURITY

Disabling password prompt for sudo users

Anoop C SLeave a comment

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Most often GNU/Linux users come across the sudo utility that allows users to run programs with the security privileges of another user (normally the superuser, or root). Its name is a concatenation of the su command (which grants the user a shell of another user, normally the superuser) and “do”, or take action. But on executing any command with sudo requests the user to provide his own password once and can be used afterwards. For that to occur the particular user must be in sudoers file (refer to my post regarding adding user for sudo privileges.

$ sudo vim /etc/sudoers
[sudo] password for anoop:

To disable this sudo password prompt edit the /etc/sudoers file as follows.

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Modifying file permissions with chmod command in GNU/Linux

Anoop C S2 Comments

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In any multi-user operating system the files have a series of features that allow us to see them, modify them or execute them for users that we define. Although there are several alternatives for achieving this, GNU/Linux uses the traditional users and groups system, allowing us to configure the file permission in various ways. By executing ls -l we can list the permissions over the various files inside the directory we are in. Look at the folowing example line displayed on executing ls -l

-rwxr-xr-x 1 user1 group1 128931 Feb 19 2000 test.txt

From the above line, first 10 characters corresponds to file permissions and we concentrate on them for the same reason.
Character 1        : It tells us whether it is a file or a directory. ‘-‘ for file and ‘d’ for directory.
Characters 2,3,4: These are the so called rwx permissions i.e, read,write and execute permissions. And 2,3 and 4 characters include the Read More »

Encrypt your GRUB passwords for better security

Anoop C SLeave a comment

The previous post was a tutorial on how to enable or password protect the GRUB. But I think it is not complete. The passwords will be  stored as plain
text if you perform the changes given in the previous post. In order to encrypt those passwords you must generate an encrypted version for each. For
this we use grub-mkpasswd-pbkdf2

g2_grub.pbkdf2

1. Open the terminal
2. Run the following command
 grub-mkpasswd-pbkdf2
3. Enter the desired password and reenter it when prompted.
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