Born2beroot

Mandatory part

Download Debian from https://www.debian.org/CD
Install VirtualBox from https://www.virtualbox.org/wiki/Downloads
Open VirtualBox
Click in New button

→ Change Machine Folder to goinfre folder and select version Debian (64-bit)
Click Continue → Continue → Create (Select Create a Virtual hard disk now) → Continue ( Select VDI) → Continue (Select Dynamically allocated) → Create.
Right click in your Virtual machine and select Setting
Select network and change from NAT to Bridged Adapter and click OK.
Start your machine and select your Debian image downloaded in step 1 and click start
choice from bar menu View → Scaled Mode (Host + C)
Select Install
Select English → United States → American English.
The hostname of your virtual machine must be your login ending with 42 (e.g., wil42). You will have to modify this hostname during your evaluation.
You can set empty Domain name
You have to implement a strong password policy.
- A strong password must be at least 8 characters long.
- It should not contain any of your personal information — specifically, your real name, username or your company name.
- It must be very unique from your previously used passwords.
- It should not contain any word spelled completely.
- A strong password should contain different types of characters, including uppercase letters, lowercase letters, numbers and characters.
💡 You can use Secure Password Generator tool : https://passwordsgenerator.net/
Re-enter password to verify
Full name for the new user
username for your account
Choose a password for the new user
Re-enter password to verify
Select your time zone
Select Guided - use entire disk and set up encrypted LVM
Select disk to partition
Select Separate /home partition
Write the changes to disks and configure LVM? Select
You need to choose a passphrese to encrypt SCSI.

What is Passphrase?

A passphrase is similar to a password. However, a password generally refers to something used to authenticate or log into a system. A password generally refers to a secret used to protect an encryption key. Commonly, an actual encryption key is derived from the passphrase and used to encrypt the protected resource.
Amount of Volume group to use for guided partitioning
Select Finish partitioning and write changes to disk
Select → Yes ←
Select No
Select Debian archive mirror countr
Select Yes
Deselect SSH server and click Continue.
Install the GRUB boot loader to your primary drive
Select /dev/sda
Click in Continue
Enter your Passphrase (Step 23).
Enter Your login and your password
lsblk **** lists information about all available or the specified block device

What is APT?

Advanced Package Tool, is a collection of tools used to install, update, remove, and otherwise manage software packages on Debian. and its derivative operating systems, including Ubuntu and Linux Mint. APT works through the use of repositories, or special directories that hold collections of software packages.

You can check this file
```
cat /etc/apt/sources.list
```
What is Aptitude

Aptitude is front-end to advanced packaging tool which adds a user interface to the functionality, thus allowing a user to interactively search for a package and install or remove it. Initially created for Debian.
Apt and Aptitude
- Apt-get being a lower level package manager is restricted only to command line, while Aptitude being a higher-level tool has a default text-only interactive interface along with option of command-line operation by entering required commands.
- While apt-get lacks UI, Aptitude has a text-only and interactive UI
- Aptitude has a better package management than apt-get
apt vs apt-get
AppArmor

AppArmor is a Mandatory Access Control framework. When enabled, AppArmor confines programs according to a set of rules that specify what files a given program can access. This proactive approach helps protect the system against both known and unknown vulnerabilities.
SSH

SSH or Secure Shell is a network communication protocol that enables two computers to communicate (c.f http or hypertext transfer protocol, which is the protocol used to transfer hypertext such as web pages) and share data. An inherent feature of ssh is that the communication between the two computers is encrypted meaning that it is suitable for use on insecure networks.

SSH provides a layer of security for information transfer between machines. Some important use cases for SSH are:
- Remote access – SSH ensures encrypted remote connections for users and processes.
- File transfers – SFTP, a secure file transfer protocol managed by SSH, provides a safe way to manipulate files over a network.
- Tunneling – This encapsulation technique provides secure data transfers. Tunneling is useful for accessing business-sensitive online materials from unsecured networks, as it can act as a handy VPN alternative.
- Network management – The SSH protocol manages network infrastructure and other parts of the system.

Install SSH
```
su - # Connect  as root
apt update
apt install openssh-server -y
```
Verify the installation by running the following command

The systemctl command is a utility which is responsible for examining and controlling the systemd system and service manager.
```
systemctl status ssh
```
💡 The default port for SSH client connections is 22

Install Vim and Change port of SSH from 22 to 4242.

apt install vim -y # Install Vim 
find / -name "sshd_config"
vi /etc/ssh/sshd_config # update again

iLocate line that read as follows:

#Port 22
#PermitRootLogin prohibit-password

Change to :

Port 4242 
PermitRootLogin no

Save and close the file.

Restart service SSH and copy ip address of Debian

systemctl restart ssh
ip address # my ip address = 10.12.178.178

Open the SSH terminal on your machine and run the following command: ssh your_username@host_ip_address and enter your password.
```
ssh [email protected] -p 4242 # -p = Port
```
Configure your operating system with the UFW firewall and thus leave only port 4242 open.
- What is UFW ?
  
  UFW, or Uncomplicated Firewall, is an interface to iptables that is geared towards simplifying the process of configuring a firewall. While iptables is a solid and flexible tool, it can be difficult for beginners to learn how to use it to properly configure a firewall. If you’re looking to get started securing your network, and you’re not sure which tool to use, UFW may be the right choice for you.
- Install UFW
```
su - 
apt update
apt install ufw
```
- Enable/Start firewall on Debian
```
ufw enable
```
- Check Status of UFW
```
ufw status
```
- Allow only port 4242 open
```
ufw allow 4242
```
IF You will change your hostname follow these steps.
- Connect as root in your SSH terminal
```
su -
```
- Display the current hostname for Debian Linux
```
hostnamectl
```
- For example, to change the system hostname to zmahmoud1337 (This command update file /etc/hostname).
  
  The syntax is as follows: hostnamectl set-hostname {name-here}
```
hostnamectl set-hostname zmahmoud1337
```
- Update file /etc/hosts
  - Before
```
#Connect As root
su -
vi /etc/hosts
```
  - After
- Reboot your machine
```
reboot
```
- I will change it again to zmahmoud42 😄
Implement a strong password policy.
- To set up a strong password policy, you have to comply with the following requirements.
  - Your password has to expire every 30 days.
  - The minimum number of days allowed before the modification of a password will be set to 2.
  - The user has to receive a warning message 7 days before their password expires.
  - Your password must be at least 10 characters long. It must contain an uppercase letter and a number. Also, it must not contain more than 3 consecutive identical characters.
  - The password must not include the name of the user.
  - The following rule does not apply to the root password: The password must have at least 7 characters that are not part of the former password.
  - Of course, your root password has to comply with this policy.
```
vi /etc/login.defs
```
- Update PASS_MAX_DAYS and PASS_MIN_DAYS and PASS_WARN_AGE and save file.
- Update old users password policy
  - user root
```
chage root -M 30 -m 2 -W 7
chage root -l
```
  - user zmahmoud (your_username)
```
chage zmahmoud -M 30 -m 2 -W 7
chage zmahmoud -l
```
- Force Users To Use Strong Passwords
→ We will use the PAM (Pluggable Authentication Modules) module to set the default password quality requirements for the system passwords, you need to install an additional module called libpam-pwquality. To do so, run the following command from Terminal:
```
apt update -y
apt install libpam-pwquality -y
```
→ After the package installation, the password policies are defined in /etc/security/pwquality.conf file. Before making any changes, backup this file.
```
cp /etc/security/pwquality.conf /etc/security/pwquality.conf.bak
```
→ You’ll need to edit the /etc/security/pwquality.conf file to set password requirements.
```
vi /etc/security/pwquality.conf
```
- The possible options in the file are:
  
  difok
  
  Number of characters in the new password that must not be present in the old password. (default 5)
  
  minlen
  
  Minimum acceptable size for the new password (plus one if credits are not disabled which is the default). (See pam_pwquality(8).) Cannot be set to lower value than 6. (default 9)
  
  dcredit
  
  The maximum credit for having digits in the new password. If less than 0 it is the minimum number of digits in the new password. (default 1)
  
  ucredit
  
  The maximum credit for having uppercase characters in the new password. If less than 0 it is the minimum number of uppercase characters in the new password. (default 1)
  
  lcredit
  
  The maximum credit for having lowercase characters in the new password. If less than 0 it is the minimum number of lowercase characters in the new password. (default 1)
  
  ocredit
  
  The maximum credit for having other characters in the new password. If less than 0 it is the minimum number of other characters in the new password. (default 1)
  
  minclass
  
  The minimum number of required classes of characters for the new password (digits, uppercase, lowercase, others). (default 0)
  
  maxrepeat
  
  The maximum number of allowed same consecutive characters in the new password. The check is disabled if the value is 0. (default 0)
  
  maxclassrepeat
  
  The maximum number of allowed consecutive characters of the same class in the new password. The check is disabled if the value is 0. (default 0)
  
  gecoscheck
  
  If nonzero, check whether the words longer than 3 characters from the GECOS field of the user's passwd entry are contained in the new password. The check is disabled if the value is 0. (default 0)
  
  badwords
  
  Space separated list of words that must not be contained in the password. These are additional words to the cracklib dictionary check. This setting can be also used by applications to emulate the gecos check for user accounts that are not created yet.
  
  dictpath
  
  Path to the cracklib dictionaries. Default is to use the cracklib default.
  
  usercheck=N
  
  If nonzero, check whether the password (with possible modifications) contains the user name in some form. It is not performed for user names shorter than 3 characters. (default 1)
  
  usersubstr=N
  
  If greater than 3 (due to the minimum length in usercheck), check whether the password contains a substring of at least N length in some form. (default 0)
  
  enforcing=N
  
  If nonzero, reject the password if it fails the checks, otherwise only print the warning. This setting applies only to the pam_pwquality module and possibly other applications that explicitly change their behavior based on it. It does not affect pwmake(1) and pwscore(1). (default 1)
→ Change.
- From
```
#difok = 7
#minlen = 8
#dcredit = 1
#ucredit = 1
#maxrepeat = 3
#usercheck = 1
#enforce_for_root
```
- To
```
difok = 7
minlen = 10
dcredit = -1
ucredit = -1
maxrepeat = 3
usercheck = 1
enforce_for_root
```
→ Change the settings to fit your desired password policy, then reboot your system.
```
reboot
# Go to VM and unlock disk sda5_crypt (Enter password)
```
Repeat step 42.

Open the SSH terminal on your machine and run the following command: ssh your_username@host_ip_address and enter your password.
```
ssh [email protected] -p 4242 # -p = Port
```
Change password of account ( your_username).

the command passwd username (where username is the name of the user whose password you want to change).
```
passwd zmahmoud
```
⚠️ After setting up your configuration files, you will have to change all the passwords of the accounts present on the virtual machine, including the root account.
Install and configure sudo following strict rules.
```
apt update
apt upgrade
apt install sudo
```
- Create group user42
```
groupadd user42
```
If you will execute command sudo it necessary add user (zmahmoud) to sudo group.
- For add your_user to sudo and user4 groups.
```
su -
usermod -aG sudo zmahmoud
usermod -aG user42 zmahmoud
```
- logout user zmahmoud and login again using SSH (Step 42)
- Create new user and add it to sudo group
```
su -
adduser newuser
usermod -aG sudo newuser
groups newuser
```
- For list all users in your machine you can use :
```
sudo cat /etc/passwd
```
To set up a strong configuration for your sudo group, you have to comply with the following requirements:

sudo mkdir /var/log/sudo # The log file has to be saved in the /var/log/sudo/
sudo visudo # (/etc/sudoers)

→ Add next lines to sudoers file

Add your username to User privilege specification
```
zmahmoud42	ALL=(ALL:ALL) ALL
```
Authentication using sudo has to be limited to 3 attempts in the event of an incorrect password.
```
Defaults	passwd_tries=3
```
A custom message of your choice has to be displayed if an error due to a wrong password occurs when using sudo.
```
Defaults	badpass_message="Password is wrong, please try again"
```
Each action using sudo has to be archived, both inputs and outputs. The log file has to be saved in the /var/log/sudo/ folder.
```
Defaults	logfile="/var/log/sudo/sudo.log"
Defaults	iolog_dir="/var/log/sudo"
Defaults	log_input
Defaults	log_output
```
The TTY mode has to be enabled for security reasons.
```
Defaults  requiretty
```
For security reasons too, the paths that can be used by sudo must be restricted.

Example: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin
```
Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"
```

Finally, you have to create a simple script called monitoring.sh. It must be developed in bash.
```
su - # Connect  as root
apt install net-tools
```

Create *monitoring.sh* in /sbin directory

# Connect  as root 
cd /sbin
vi monitoring.sh

Copy code and past in *monitoring.sh file*

#!/bin/sh
# https://github.com/ZakariaMahmoud
total_mem_kilo=$(free --kilo | grep "Mem:" | awk '{print $2}')
total_mem_mega=$(free --mega | grep "Mem:" | awk '{print $2}')
used_mem_kilo=$(free --kilo | grep "Mem:" | awk '{print $3}')
used_mem_mega=$(free --mega | grep "Mem:" | awk '{print $3}')
memory_per=`free --kilo | grep "Mem:" | awk '{printf("%.2f", $3*100/$2)}'`
disk_usage_gb=$(df  --total -h | grep "total" | awk '{print $2 "b"}')
disk_usage_m=$(df  --total -m| grep "total" | awk '{print $3}')
cpu_physical=`cat /proc/cpuinfo | grep physical\ id | sort | uniq | wc -l`
cpu_load=`top -n1 -b | grep "%Cpu(s):" | awk '{print $2}'`

if [ `lsblk | grep lvm | wc -l` -gt 0 ]
then
	lvm="yes"
else
	lvm= "no"
fi

wall "	#Architecture: `uname -a`
	#CPU physical : `cat /proc/cpuinfo | grep physical\ id | sort | uniq | wc -l`
	#vCPU : `cat /proc/cpuinfo | grep processor | wc -l`
	#Memory Usage: $used_mem_mega/$total_mem_mega"MB "($memory_per%)
	#Disk Usage: $disk_usage_m/$disk_usage_gb
	#CPU load: $cpu_load%
	#Last boot: `who -b | awk '{print $3 " " $4}'`
	#LVM use: $lvm
	#Connexions TCP : ` netstat | grep "ESTABLISHED" | wc -l` ESTABLISHED
	#User log: `who | wc -l`
	#Network: IP `hostname -I`(`ip a | grep link/ether | awk '{print $2}'`)
	#Sudo : `journalctl -q | grep sudo | grep TTY | wc -l` cmd"

Add execute permission to monitoring.sh.

chmod +x monitoring.sh
./monitoring.sh # Test script

Use Crontab

The cron command-line utility, also known as cron job is a job scheduler on Unix-like operating systems. Users who set up and maintain software environments use cron to schedule jobs to run periodically at fixed times, dates, or intervals.
Type the following command to enter crontab
```
# Connect  as root 
crontab -e -u sbin
```
To get crontab to run a monitoring.sh every 10 minutes you could type as follow
```
*/10 * * * * /sbin/monitoring.sh
```
Save and close the file
- Where
  1. The asterisk (*) operator specifies all possible values for a field. For example, an asterisk in the hour time field would be equivalent to every hour or an asterisk in the month field would be equivalent to every month.
  2. The */10 is used in conjunction with ranges. For example, 0-23/2 can be used in the hours field to specify command execution every other hour. Steps are also permitted after an asterisk, so if you want to say every two hours just use */2. In this example, */10 in the minutes field to specify command execution every 10 minute.

Name		Name	Last commit message	Last commit date
Latest commit History 1 Commit
Born2beroot 54151631cd3f41fd860740a58b9eee40		Born2beroot 54151631cd3f41fd860740a58b9eee40
README.md		README.md

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