Introduction when it is booting up to shutting

Introduction :

      A computer is secure if you can depend on it and its  software to behave as you expect I this assignment I will writer about how Linux provides security to you information. The major technical areas of computer security are usually represented by CIA confidentiality, integrity, and authentication or availability. It means that information cannot access by unauthorized people.

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Linux is the most important free software it has developed into a an operating for business , education , and personal productivity. Linux is so different because of its free implementation of Unix

                 Linux was originally developed as a hobby project by LINUX Torvalds. It was inspired by minx, a small UNIX system developed by Andy Tanenbaum On October 5, 1991, Linus announced the first “official” version of Linux, which was version 0.02


Security in LINUX

BIOS Security:

                An operating system is needed security when  it is booting up to shutting down  Operating System is needed security from its booting up to shutting down. If attacker has access to the BIOS, nothing is safe then  .When an operating system  boot up this is  very important whether an unauthorized user has full physical access to computer. The BIOS is the lowest level of software that configures or manipulates of x86 based hardware. LILO and other Linux boot methods access the BIOS to determine

how to boot up Linux machine.

          We can use BIOS password to prevent from unauthorized physical access to change Bios setting BIOS password is needed.

Example are disallow booting from floppy drivers and password to acess of some bios features. manyX86 BIOS’s also Allow to specify various other good security settings

Boot loder security:

          At this moment we prevents an illegal user to change the BIOS settings by setting BIOS password. But In Linux Operating System there is an option to change the root password during booting. The two common boot loaders for Linux are LILO (Linux Loader) and GRUB (Grand Unified Boot loader).

LILO security

Grub security

Users and Groups

User accounts are important to verify the identity of the person using a

computer system. verifying the accounts of user the system is able to

determine  that if the user is permitted to log into the system and, if so, which information  the user is allowed to access.

There are three types of users:

i) Root

ii) Normal users

iii) System users

User authorisations & authorization

The normal user authentication is based upon the user being able to provide the correct username and password. The username is not something that has to be kept secret as it is readable by anyone on the system however the password is encrypted and should only be known by the user. The algorithm used to encrypt the password is a one way password which cannot be reversed. Instead when a user enters their password it is encrypted using the same algorithm and compared against the original.

Traditionally in UNIX the password was kept in the /etc/passwd file which was readable by all users on the system. Modern Linux distributions use a shadow password file with restricted read permission


It’s the most important security feature and basic mean of authentication its important to set secure ungues sable password security is most critical means to protect a system a good password is always desireable not to be compromised the system

Linux Have some characteristics of password storing mechanism.

i)             In a file that is readable only by root.

ii)            ii) In a one way hash format.

This how you can make your password strong

1 Use of shadow passwords.

2 not use only words or numbers.

3 not use recognizable words.

4 not use hacker terminology.

5 not use personal Information.

6 not invert recognizable words.

7 Make the password at least eight characters long.

8 Mix upper and lower case letters.

9 Mix letters and numbers.

10 Include non-alphanumeric characters


File Systems Security

File systems security is important to keep a system safe. By changing

important file like server configuration, network configuration and system

configuration a computer  can be compromised. A file system is the methods and data structures that is use by operating system uses to keep the track of files on a disk or partition that is, the way the files are organized on the disk. The central concepts of Linux file systems are super block, inode, data block, directory block, and indirection block. The super block contains information about the file system as a whole, such as its size. An inode contains all information about a file, except its name. The name is stored in the directory, together with the number of the inode. A directory entry consists of a filename and the number of the inode which represents the file.


NFS (Network File System) Security.

 NFS is a very widely-used file sharing protocol. It allows servers running nfsd and mountd to export entire file systems to other machines using NFS filesystem support built in to their kernels or some other client support if they are not Linux machines. mountd keeps track of mounted file systems in /etc/mtab, and can display them with show amount.

if you must use NFS, make sure that you export to only those machines that you really need. Don’t export your entire root directory export only directories you need to export

Securing NFS

Before implementing an NFS server first we have to secure the

PORTMAP services. The PORTMAP service is a dynamic port assignment

daemon for RPC services. It has weak authentication mechanisms and hasthe ability to assign a wide range of ports for the services it controls. For these reasons, it is difficult to secure Linux provides a number of way to secure the PORTMAP, for this we have to do following things

? Protect portmap With TCP Wrappers.

? Protect portmap With iptables



Firewalls are used to control  what information is allowed into and out of your local network.  the firewall host is connected to the Internet and your local LAN, and the only access from your LAN to the Internet is through the firewall. This way the firewall can control what is coming in and going out  from the Internet and your LAN.

There are a number of types of firewalls and methods of setting them up. Linux machines make  good firewalls. Firewall code can be built right into 2.0 and higher kernels. The user-space tools ipfwadm for 2.0 kernels and ipchains for 2.2 kernels, allows you to change, on the fly, the types of network traffic you allow. You can also log particular types of network traffic .Firewalls are a very useful and important technique in securing your network

Email Security

When a email send from a computer it passes several points and give a chance to attacker to read it or change it  some times email maybe lose we never want this that’s why security of email is needed

We can secure email by GnuPG(GNU privacy guard ) this software secure the communication and data storage this software can encrypt data and create digital signatures

Advantages of Linux over Windows

We will have to  take a look at 10 of the important reasons why LINUX is better then windows.


1:Open Source

It is like when you buy a car, but you cannot see what’s under the hood Similar is the case with when you use a Windows-powered system.

Linux is totally an open source project. You can check source code of a Linux OS, which is the plus  point for lunix

2:Can revive older computers

Operating system is updating every day after hardware requirement increase if you buy windows 10 you have to meet the minimum requirements to run it properly you can not run it on low end system.

On the other hand Linux  you don’t need to think about it you can do you use it with older computer system to achieve your task    . It doesn’t mean that every Linux would work with 256 MB of RAM coupled with outdated processor. But , there are choices which you can install on  low-end systems like PUPYY LINUX

For being a good  Operating System , Linux  give use good range of systems low-end or high-end. In contrast, Windows OS need higher hardware requirement.

3:Software Updates

          IN Microsoft a software update when there a some problems or if something major needs to be fixed. On in linux  Linux you will notice that there is a lot of software update to fix a problem and much quick and it faster updates.


Windows OS is vulnerable. It can be attack of hack or it can be compromised by a viruse but Linus is more secure according to it security features

The way Linux work it make Linux more secure  operating system. General, the process of package management, the concept of repositories, and a few more features makes it possible for Linux to be more secure than Windows

You need to install antivirus and you also need to buy a antivirus to save your computer form virus and hackers. But on other hand , Linux does not need to use there is some , but it is often unnecessary when you have a Linux system.

Being secure  nature can make things easier for you and save money also because you don’t need to pay for  Antivirus software.


5 Variety Of Distributions

There are no flavour’s of Windows. There is some different plans & packages which different in licensing terms, the activation period, packaged features, and price.

In Linux  you will find tons of Linux distribution catered for a different needs. So, you have a option to  choose and  install any of the available Linux distros according to your requirements


Linux distributions for hackers,

Linux distributions for programmers,

Linux distributions for extremely old computers.

There is a Linux for everyone.

6: Customization options

One of the major advantage of using Linux instead of Windows is customization options. If you like change your system’s looks Linux is just flawless for you. Linux customization have a lot of option in it.

Other then  installing themes, you have a lot of beautiful icon themes. In addition to that, you can use Conky to display system information on the desktop in the cool way you want. Unnecessary to say that you can do a lot around Wallpapers in Linux.

7:Free to Use

Linux is free to use you don’t need to buy it. But windows is not free

You don’t need  to pay money to buy Linux distro (such as Ubuntu, Fedora). It is totally .

If you get some thing free and its excellent also in use you save your money and you can spend that money on upgrading your system.

8: Reliability

In windows we know that it is become hard day after day your system start slowdown or crash the you will need to re install it .

If you r using Linux you don’t have to worry about re installing it  it will work faster and smother. Linux helps your system run smooth for a longer period

In Windows, you just have to do rebooting for everything when its slowdown or crash.


Microsoft try to collect the data for user . but it does not look good with Microsoft’s latest Windows 10. Widows 10 already received a lot of criticism on it , what widow should collect or what not .

If you r using widows 10 you can only head into the privacy settings to know over there everything is enable by default. Even if you choose out to send Microsoft info about your data it is still being collected. Of course, Microsoft will not bother revealing it officially with a press statement but it surely does. So you would need a set of tools to disable the spying modules of Windows.

In Linux there is perfect solution for privacy. In Linux distribution It does not collect like  data like windows. and you will not need any additional tools to protect your privacy .







Linux operating systems security is extremely good. there number of option to provides information security. There is number of tools is available for Linux to secure system. Sometimes default configuration of Linux is not secure .So we have to careful for that need use Linux it is possible to establish standard security policy CIA. Its better then windows LINUX have good privacy its free and it extremely good for programmers there is a lot of software option according to your scope of work.


• Security Reference Info

• Practical UNIX & Internet Security, Second Ed.

O’Reilly & Assoc, ISBN 1565921488

• Building Internet Firewalls, Second Edition

O’Reilly & Assoc, ISBN 1565928717

• Torvalds, Linus (1999).  “The Linux Kernel Source v 2.4.2”


• Thompson, B (1994, March) Linux vs. Windows and OS/2.  Linux Journal Online.  Retrieved October 2002 from

• linux/html/sect_03_04.html