INTRODUCTION COMPUTER VIRUSES

Risk Factory and Security in Internet access

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Risk Factory and Security in Internet access

Software Firewall

Software firewalls are programs that can be installed on ones computer like any other program. Therefore, it is ideal for individual and home user. The users can configure a software firewall, for type of patterns of external threats of internal risks, like internal program trying to contact remote computer without permission by the user. Therefore, software firewall provided a best protection for email worms of Trojan horse programs.

Secure Communication

The Need and Parts of a Secure Communication

The internet is the high-way for information exchange in the modern world. However, from the best level, the information transmission in the Internet happens in plaintext format, and thus it is said that the communication is un-secure when connected about eavesdropping and modification of information secure in a shared network, like Internet, so that it can facilitate commercial and business Internet transaction.

Firewall Type and Techniques

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A firewall is a system enforces an access control policy between two networks while sitting in-between the two networks. The policy is to block one part of the traffic while permitting the other part, based on the firewalls configuration. The firewall is implemented in software and hardware levels.

Hardware Firewall

The hardware firewalls are intended to protect every machine on a local network. It is available as a stand-alone product and also found in broadband routers. A hardware firewall can be effective with little or no extra configuration. The technique used by a hardware firewall to defect threats is called packet filtering, which examines the header of a packet to determine its source and destination addresses and port. This information is compared to a set of rules that determine whether the packet is to be forwarded or dropped. However, hardware firewall is non-effective for email worms of Trojan horses.

Network Firewalls

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The need for a Firewall

Today most organizations are characterized with internal computer networks, and they use this facility mostly to store and exchange information that is private to them Meantime, there are situation is which, need arise to have communication between outside world and the local network. Most organizations prefer if they have a control for the latter type of communication, because unauthorized users would use this advantage to steal valuable information or to penetrate the control of the systems. The solution come up with firewalls, where a firewall is a security system intended to protect an organizations network against external threats, such as hackers, coming from another network, such as the Internet. The most important question one would seek answer to are.

· How a firewall looks like and what is the type of firewall?

· How a firewall works and defends attacks?

Hacking and Password Security

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The most authentication method for identification legitimate users of a computer system or a service is user name and password pair In this effort, the user name is the unique identify of a particular user among all the user and it is used as an index to reserve all the facilities belong to that particular user within the scope of the system. In contrast, the password is something secret between the system and the user and the system always make sure to hide it from the visibility all the time.

Therefore, when someone is typing the password, the characters will be substitute with difference characters to avoid it from gained by a third party. However, to firmly understand the concept, one would find answers to the following questions.

· Why authentication is so important?

· What is the strength of password security?

In a multi-user computing platform, the authentication is the process by which the system validates the user’s login information. The login information is compared against as authorized users list, and if the system detects a mach, this system identifies the user as a legitimate user and the access is granted to the extent specified in the permission list for that user. The authentication require may be require may be supported to process a user’s personal files, personal information, email information, email account, bank account, enabling or disabling a service like database server, access to remote systems, or a transaction like money transfer.

One could imagine the situation if an intruder gains the user name and password of a legitimate user. The intruder can offer great suspires not only to the legitimate user, but to other users as well, The intruder may access other machines on the network and capture information about the other users, penetrate the control of the system and even breach of the security of those systems. Having gained the access to someone’s online bank account may bell items to the actual owners account or transfer money to someone else’s account.

There are many concerns for password protected access control mechanism. From the user’s perspective, many users do not gain the actual power of this method, because it is something one has to keep in mind, and thus the users tend to use short password of predictable password. The second threat for password hacking. In this effort hackers use many tools, such as dictionary programs and sniffers, to assist them.

In the dictionary attack, the pregame passes every work in a dictionary to the authentication system. If a correct match is found, the system grants the access to the dictionary program and the matching word would be the password. Another similar approach is the brute force attack, where each and every combination of an alphabet is tried. However, if the password is unpredictable and sufficiently large, the dictionary and brute force attacks can mostly be defeated.

General Precautions

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After understanding the potential risk of virus infection, one should always try to implement necessary precaution to get rid from viruses. The following is a list of precautions one could follow in this effort.

Install anti-virus and anti-spyware software.

Scan removable media before copying files or executing programe

Do not open any file attached to an email from an unknown, suspicious of untrustworthy sources.

Exercise caution when downloading files from the Internet and always ensure that the source is legitimate and reputable one

Take backup of important files in regular basis and store it in a storage area.

Virus Transmission Methods

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When a virus get activated as a result pf executing a virus infected program, the virus tries to copy itself into uninfected programs in the same computer or in other computers connected to it over a network. And repeatedly the newly infected programs try to infect yet more programs. Removable media, such as floppy diskettes and USB sticks has remained in the position as a major source of virus carriers form the past.

The third major source of viruses is email attachments. According to ICSA, infection that spread through e-mail attachments. The source of macro viruses, increased from 2 percent in year 1998 to over 60 percent in year 2000.

Virus Dangers

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Virus Dangers

People have to be always cautious about computer viruses, because viruses can spoil people’s money, time resources and irreplaceable data.

Virus Classifications

A computer virus is explained as a computer program designed to replicate itself by infecting other files or system areas and then making copies of itself. It may be benign or will operate without the knowledge or desire of the computer viruses can be categorized in to one of following broad virus categories.

Viruses- Usually the virus activity within a single computer

Trojan horse -when run, a Trojan horse does something harmful to the computer system, but disguised as something useful. Unlike viruses , Trojan horses usually do not make copies of themselves.

Worm- Is a computer program that propagates it self across computers, creating copies of itself in each computer, infecting the entire network.

The following summarized how the viruses get evolved over time , expanding their capabilities and scope.

Macro viruses; These viruses come attached to documents and when that document is opened the virus gets activated.

Parasitic or File Infector viruses: These viruses attach themselves to or replace executable files, such as, files with extensions.com, .exe or even.sys, .drv and bin.

Bootstrap viruses : Boot sector is a small portion of a disk reserved for the bootstrap loader program of an operating system. When a bootstrap virus infects this bootstrap program, the virus gets activated at each time the operating system is loaded.

Multi-partite viruses: These viruses often infect multiple targets, for instance both files and bootstrap of a disk.

Polymorphic viruses: These viruses are capable of mutating over time to escape from anti-virus software.

Stealth viruses: These viruses can conceal themselves in memory.

Retro viruses: These viruses are designed to attack and defeat anti-virus software.

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Computer Viruses

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Risk factors and security in Internet Access

Computer Viruses

Virus Symptoms

When someone hears the word’ Virus”, it is natural that he/she gets a sudden shock. The behavior of a computer virus is very much similar to a biological virus in that both are intentionally harmful to the normal function of a system. The following may be indications that someone’s computer is infected by a computer virus.

Programs do not work as usual!
Parts of the system become unstable!
Unexpected error and warning messages!
Invaded storage and memory Ares!
Unusual activities in the system!
Computer is slowing down!