B2BR Evaluation

Question 1

how to retreive the signature?

Answer 1

shasum filename.vdi

Question 2

How does a virtual machine work ?

Answer 2

A VM provides a virtual environment for running applications, offering flexibility and isolation.

1. Imagine a computer within a computer: This is the core concept of a VM.
2. Each VM has its own operating system: Like a separate computer.

3.A hypervisor manages the VMs: It controls resource allocation and ensures they run smoothly.

4. Hypervisor Types:
   Type 1 (bare-metal): Directly installed on hardware.
   Type 2 (hosted): Runs within another operating system.

Question 3

Why did I choose Debian over Rocky?

Answer 3

Larger community: More resources and support available for beginners.

User-friendly package management: APT is intuitive and easy to use.

Extensive documentation: Many guides and tutorials available.

Stability: Known for its reliability and security. Longer release cycle. (new feautres intro gradually > less bugs)

Question 4

What is the difference between Rocky and Debian?

Answer 4

Rocky Linux is a community-driven Linux distribution based on Red Hat Enterprise Linux (RHEL). It’s a good choice for those familiar with RHEL’s ecosystem and looking for a free alternative.

Debian is another popular Linux distribution known for its stability, security, and large package repository. It’s a great option for beginners due to its user-friendly approach and extensive documentation.

Question 5

What is the purpose of virtual machine?

Answer 5

Flexibility: Diff OS can be run on same computer

Isolation: Each VM run independant of each other and the host.

Efficiency: VMs can improve resource utilization by consolidating multiple workload into single physical machine.

Testing & Development: 1 App, tested on different environment (IOS, Andorid, Windows)

Question 6

The difference between aptitude and apt

Answer 6

apt

Basic command-line interface: Provides essential commands for installing, removing, and updating packages.

Simpler syntax: Generally easier to use for basic package management tasks.

Suitable for most users: Adequately handles most package management needs.

aptitude

Advanced command-line interface: Offers more features and flexibility for complex package management scenarios.

Interactive mode: Allows users to resolve dependency conflicts interactively.

Better dependency handling: Can handle complex dependency issues more effectively.

Suitable for experienced users: More suited for users who require advanced package management capabilities.

Question 7

What is APParmor?

Answer 7

Security framework (Mandatory Access Control), that restricts application permissions, preventing unauthorized access and improving system security. It’s often used in environments where data security is critical.

Mandatory because, restrictions are enforced at kernal level. So apps cant by-pass the controls.

Question 8

Check AppArmor status

Answer 8

sudo aa-status

Question 9

How to check if OS is Debian or Rocky?

Answer 9

cat /etc/os-release

Question 10

1. How do you check if the UFW service is started?
2. How do you check if the ssh service is started?

Answer 10

1. sudo systemctl status ufw
2. sudo systemctl status ssh

Question 11

Verify UFW is installed

Verify that is functioning correctly

Answer 11

dpkg -l | grep ufw

sudo ufw status verbose

Question 12

What is ufw?

Answer 12

It stands for uncomplicated firewall and is an easy to use program to manage a netfilter firewall. It can control incoming and outgoing network traffic.

Question 13

Why is ufw useful?

Answer 13

UFW abstracts the underlying complexity of iptables, allowing for faster setup and easier rule management, which helps users implement effective firewall policies with minimal effort and reduced risk of errors.

Question 14

List active rules for UFW

Answer 14

sudo ufw status numbered

Question 15

Add new rule to UFW (add port 8080)

Verify added to list

Answer 15

sudo ufw allow 8080

sudo ufw status verbose

Question 16

Delete new rule from UFW (remove port 8080)

Answer 16

sudo ufw delete allow 8080

Question 17

Check user exist

Check if they belong to sudo and user42 groups

Answer 17

getent passwd kilangov

groups kilangov

Question 18

1. How do you create a new user?
2. How do you set their password?

Answer 18

1. sudo useradd newusername
2. sudo passwd newusername

Question 19

How do you check the password policy?

How do you check Password status?

Answer 19

For password requirement:
sudo nano /etc/pam.d/common-password

Password expiration:
sudo nano /etc/login.defs

Password status:
sudo chage -l username

Question 20

Explain your password policy implementation

Answer 20

retry=3 : only 3 retries
minlen=10 : at least be 10 char
ucredit=-1 : at least one uppercase
lcredit=-1 : at least one lowercase
dcredit=-1 : at least one digit
maxrepeat=3 : no more than 3 consecutive characters
usercheck=0 : can’t have the username
enforce_for_root : make sure the root also needs to comform to the rules
difok=7 at least 7 char not from the former password

Question 21

1. How to set up a new group called “evaluating”?
2. How do you assign a user to this group?
3. How do you check if the user is part of the group?

Answer 21

1. sudo groupadd evaluating
2. usermod -aG evaluating username
3. sudo groups username OR getent group sudo

Question 22

How to check that the hostname of the machine is correctly formatted as follows: login42 (login of the student being evaluated)

Answer 22

hostnamectl

Question 23

How do you modify the host name?

(you should also be able to restore the machine with the original hostname/ or just rename it again)

Answer 23

1. su
2. hostnamectl set-hostname newname
3. nano /etc/hosts
4. reboot

Question 24

How do you show the partitions on the machine?

Answer 24

lsblk

Question 25

Explain how LVM works

Answer 25

1. Physical Disk allocates storage (sda) for VM through hypervisor. 2. Physical disk of VM (sda) is partitioned into sda1 and sda2. Max 3 PP and 1 EP 3. sda2 is the extended partition, used by LVM. sda2 becomes physical volume. and used to create the Volume Group. 4. Logical volume is created from the Volume Group. 5. Logical volume is mounted onto a file system.

Question 26

Why is LVM beneficial?

Answer 26

Flexibility in Storage Management: 1. Dynamic Resizing: Unlike traditional partitions, which have fixed sizes, LVM allows you to resize logical volumes (LVs) on the fly. You can increase or decrease the size of a volume without needing to unmount it or reboot the system, making it easy to adjust to changing storage needs. 2. Combine Multiple Disks: LVM enables you to combine multiple physical disks into a single volume group (VG), creating a large pool of storage that can be allocated as needed. This means you’re not limited by the size of a single physical disk.

Question 27

How do you check if the sudo program is properly installed?

Answer 27

dpkg -l | grep sudo sudo -l

Question 28

Assign new user to "sudo" group

Answer 28

sudo usermod -aG sudo newusername

Question 29

What is sudo?

Answer 29

sudo stands for "superuser do." It is a command in Unix-like operating systems that allows a permitted user to execute a command as the superuser (root) or another user, as specified by the security policy. It's used to perform tasks that require higher privileges, such as installing software, modifying system settings, or managing other users.

Question 30

How does sudo work?

Answer 30

When a user runs a command with sudo, the system checks the /etc/sudoers file to determine whether the user has the necessary permissions to run that command. If authorized, the command is executed with elevated privileges.

Question 31

Where did you configure the sudo rules from the subject?

Answer 31

sudo nano /etc/sudoers OR sudo visudo

Question 32

1. Verify that the SSH Service is Installed 2. Verify that the SSH Service is Functioning Correctly

Answer 32

1. dpkg -l | grep openssh-server 2. sudo systemctl status ssh

Question 33

Basic Explanation of SSH

Answer 33

What SSH Is: SSH (Secure Shell) is a protocol that allows users to securely access and manage a remote server or computer over an unsecured network. It encrypts the connection, ensuring that data sent between the client and server is secure. Why SSH Is Important: SSH is important because it provides a secure method for remote login and command execution, protecting sensitive data from being intercepted by attackers. It is widely used for system administration, file transfers, and secure communication between devices.

Question 34

Verify that SSH Uses Only Port 4242

Answer 34

sudo nano /etc/ssh/sshd_config

Question 35

Help to Use SSH to Connect with the New User Ensure ssh cannot be used with root user

Answer 35

ssh -p 4242 newusername@ nano /etc/ssh/sshd_config ---> PermitRootLogin no

Question 36

Show how the script runs every 10 minutes

Answer 36

sudo crontab -u root -e crontab is the file, for (-u) user root, -e = edit

Question 37

What is cron?

Answer 37

A job scheduler, used to execute a command to an operating system or server for a job at a specified time.

Question 38

,How does the monitoring script work?

Answer 38

/home/kilangov/monitoring.sh

Question 39

How to stop the cronjob without editing the crontab file?

Answer 39

sudo systemctl stop cron (temp) sudo systemctl disable cron (perm)