Securities in Linux.

As the Internet is  being cheaper and  global, the chances of  destruction of  whole computer system has been increased due to  hazardous and malicious data. Various virus, worms, Trojans, are affecting computers badly sometime 70-80 percent of entire network had been affected badly.  In this portion, you will learn some procedures and commonly-used software to make you sure about more security of  your Linux system.

Why Security is necessary?

As you know that internet is the networking of the networks. So if any data passes through one computer to another it may pass through several other points along the way. It can be halt, changed, or can be converted by the hackers that can be very dangerous for  computers. We should always remember that no computer can be completely safe. There are always a little chances of  harm. We can just enhance the security of the system by using different types of means like anti viral injection or making complex security code and filters. 

Developing A Security Policy

A security policy can be develop in such a way that the user except you can not interfere in the infrastructure and  he/she is allowed to install some more software or add something or downloading by getting administrator permission without doing any changes in the infrastructure. User can make his/her own user name and create password that allows him/her to do some thing that is not allowed without doing this like downloading, reading articles etc. The policy should be so simple that everyone can assess and follow it. The privacy of the other user should also be safe. It's administrative liability. Some Security policy procedure is given below, which is generally applied by the administrator and the user. 

Physical Security

Physical security is the top most security which comes in the first priority. This types of  Physical security secure the hardware of the system including RAM, hard disk, processor, system files, system configuration etc. Generally all Linux production systems are physically secured. 

Host Security Action 

Host security is the primary major region after physical region on which the administrator concentrates most. This policy ensures the user that they are safe while using their computer system working in your Linux environment. It is the duty of  local security administrator to choose good passwords, securing their host's local network services, keeping good accounting records, and upgrading programs. Even the best system administrator can make mistakes and forget things. So if you have a larger Linux environment, it would be an excellent policy to write scripts for executing all Linux security action items automatically.

Local Network Security

Network security is as necessary as local host security. With hundreds, thousands, or more computers on the same network, you can't rely on each one of those systems being secure. Ensuring that only authorized users can use your network, building firewalls, using strong encryption, and ensuring there are no "rogue" (that is, unsecured) machines on your network are all part of the network security administrator's duties.

This document will discuss some of the techniques used to secure your site, and hopefully show you some of the ways to prevent an intruder from gaining access to what you are trying to protect.

Retiring Linux Servers with Sensitive Data

Retiring Linux server with sensitive data means to retire servers in such a way that no prior data can be recovered later via any means.  For  removing data  the Disk Sanitizer tool can be used. This tool can be operated from a floppy disk and it removes data which can not be recovered later.  

Backups

Backup system is the safe system to prevent the losing of the data, in which the wanted file has been copied and put up in a particular place in the hard disk. Accidentally or by virus attack when the original file crashes or losses, then recalling backup file is very useful and  trendy formula which recovers the data after specifying   the exact name, and types of the file. If your system is crashed or infected by virus then there the backups become invaluable. 

Disk Partitions

Servers must be classified into several partitions for booting, logging, root partitioning and for third party applications. This criteria protect the system by preventing the overlapping and  reduces the chances of over coding. 

Firewall 

Firewall is a set of related programs which protect the interference of the outsider into a LAN.  It ensures the LAN users that their data are safe from the reach ness of the outsiders. It can be used either in hardware and software or both in the places. It works as a censor board. It checks all the data and blocks and prevent the harmful and malicious data to reach within intranet. So Firewall is very useful for enhancing the security in Linux. 

SELinux

SELinux is an advanced technology for securing Linux systems. It is a research prototype of  Linux kernel and it is used for multi-level security and role based access control.

Removing Unnecessary Software Packages (RPMs)

RPM (Red-hat package manager) is a powerful command line driven package management system which is used for installing, uninstalling, querying, updating and verification of computer software packages. Unnecessary software packages may be the one reason of  insecurity in Linux. For this we have to identify the required package, which is beneficial and have a chances to be used in the future or it is being used. Other worthless packages must be removed with the help of  RPMs. If you do this you will have to be worry about only the existence packages. Packages like FTP and Telnet daemons should not be installed if you have not a very big networks. 

For getting a list of all installed RPMs you can use the following command:
rpm -qa

If you want to know more about a particular RPM, run:
rpm -qi <package_name>


Enforcing Stronger Passwords

Enforcing stronger password is another a big tool for enhancing the chances of security system in Linux. The system must not accept the easier password. The password can be only easier when it is written only in a single version like, alphabetic or numeric. We should make up our security system in such as way that the system accept the password when it is written with the combination of  alphabetic and numeric with have at least one special symbol. It should have at least eight character long, but should be less then thirteen character. The password must not be too complex to be learn. Because many times users write the password in any place which can be hacked easily and all the security system will be worthless. There are some following suggestions, which can be used at the time of  determining configuration.  
- Minimum length of password must be 8
- Minimum number of lower case letters must be 1
- Minimum number of upper case letters must be 1
- Minimum number of digits must be 1
- Minimum number of special characters must be 1