18-03-2011, 12:08 PM
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1. INTRODUCTION
Do viruses and all the other nasties in cyberspace matter? Do they really do much harm? Imagine that no one has updated your anti-virus software for a few months. When they do, you find that your accounts spreadsheets are infected with a new virus that changes figures at random. Naturally you keep backups. But you might have been backing up infected files for months. How do you know which figures to trust? Now imagine that a new email virus has been released. Your company is receiving so many emails that you decide to shut down your email gateway altogether and miss an urgent order from a big customer. Imagine that a friend emails you some files he found on the Internet. You open them and trigger a virus that mails confidential documents to everyone in your address book including your competitors. Finally, imagine that you accidentally send another company, a report that carries a virus. Will they feel safe to do business with you again? Today new viruses sweep the planet in hours and virus scares are major news.
A computer virus is a computer program that can spread across computers and networks by making copies of itself, usually without the user’s knowledge. Viruses can have harmful side effects. These can range from displaying irritating messages to deleting all the files on your computer.
A virus program has to be run before it can infect your computer. Viruses have ways of making sure that this happens. They can attach themselves to other programs or hide in code that is run automatically when you open certain types of files. The virus can copy itself to other files or disks and make changes on your computer. Virus side effects, often called the payload, are the aspect of most interest to users. Password-protecting the documents on a particular day, mailing information about the user and machine to an address somewhere are some of the harmful side effects of viruses. Various kinds of viruses include macro virus, parasitic or file virus, Boot virus,
E-mails are the biggest source of viruses. Usually they come as attachments with emails. The Internet caused the spreading of viruses around the globe. The threat level depends on the particular code used in the WebPages and the security measures taken by service providers and by you. One solution to prevent the viruses is anti-virus softwares. Anti-virus software can detect viruses, prevent access to infected files and often eliminate the infection.
Computer viruses are starting to affect mobile phones too. The virus is rare and is unlikely to cause much damage. Anti-virus experts expect that as mobile phones become more sophisticated they will be targeted by virus writers. Some firms are already working on anti-virus software for mobile phones. VBS/Timo-A, Love Bug,Timofonica,CABIR,aka ACE-? and UNAVAILABLE are some of the viruses that affect the mobile phones
2. BASIC CONCEPTS
2.1.What is a virus?
A computer virus is a computer program that can spread across computers and networks by making copies of itself, usually without the user’s knowledge. Viruses can have harmful side-effects. These can range from displaying irritating messages to deleting all the files on your computer.
2.2.Evolution of virus
In the mid-1980s Basit and Amjad Alvi of Lahore, Pakistan discovered that people were pirating their software. They responded by writing the first computer virus, a program that would put a copy of itself and a copyright message on any floppy disk copies their customers made. From these simple beginnings, an entire virus counter-culture has emerged. Today new viruses sweep the planet in hours and virus scares are major news.
How does a virus infect computers?
A virus program has to be run before it can infect your computer. Viruses have ways of making sure that this happens. They can attach themselves to other programs or hide in code that is run automatically when you open certain types of files. You might receive an infected file on a disk, in an email attachment, or in a download from the internet. As soon as you launch the file, the virus code runs. Then the virus can copy itself to other files or disks and make changes on your computer.
Who writes viruses?
Virus writers don’t gain in financial or career terms; they rarely achieve real fame; and, unlike hackers, they don’t usually target particular victims, since viruses spread too indiscriminately. Virus writers tend to be male, under 25 and single. Viruses also give their writers powers in cyberspace that they could never hope to have in the real world.
2.3.Virus side effects(Payload)
Virus side-effects are often called the payload. Viruses can disable our computer hardware, Can change the figures of an accounts spreadsheets at random, Adversely affects our email contacts and business domain, Can attack on web servers…
Messages -WM97/Jerk displays the message ‘I think (user’s name) is a big stupid jerk!’
Denying access -WM97/NightShade password-protects the current document on Friday 13th.
Data theft- Troj/LoveLet-A emails information about the user and machine to an address in the Philippines.
Corrupting data -XM/Compatable makes changes to the data in Excel spreadsheets.
Deleting data -Michelangelo overwrites parts of the hard disk on March 6th.
Disabling Hardware -CIH or Chernobyl (W95/CIH-10xx)
attempts to overwrite the BIOS on April 26th, making the machine unusable.
Crashing servers-Melissa or Explore Zip, which spread via email, can generate so much mail that servers crash.
There is a threat to confidentiality too. Melissa can forward documents, which may contain sensitive information, to anyone in your address book. Viruses can seriously damage your credibility. If you send infected documents to customers, they may refuse to do business with you or demand compensation. Sometimes you risk embarrassment as well as a damaged business reputation. WM/Polypost, for example, places copies of your documents in your name on alt.sex usenet newsgroups.
1. INTRODUCTION
Do viruses and all the other nasties in cyberspace matter? Do they really do much harm? Imagine that no one has updated your anti-virus software for a few months. When they do, you find that your accounts spreadsheets are infected with a new virus that changes figures at random. Naturally you keep backups. But you might have been backing up infected files for months. How do you know which figures to trust? Now imagine that a new email virus has been released. Your company is receiving so many emails that you decide to shut down your email gateway altogether and miss an urgent order from a big customer. Imagine that a friend emails you some files he found on the Internet. You open them and trigger a virus that mails confidential documents to everyone in your address book including your competitors. Finally, imagine that you accidentally send another company, a report that carries a virus. Will they feel safe to do business with you again? Today new viruses sweep the planet in hours and virus scares are major news.
A computer virus is a computer program that can spread across computers and networks by making copies of itself, usually without the user’s knowledge. Viruses can have harmful side effects. These can range from displaying irritating messages to deleting all the files on your computer.
A virus program has to be run before it can infect your computer. Viruses have ways of making sure that this happens. They can attach themselves to other programs or hide in code that is run automatically when you open certain types of files. The virus can copy itself to other files or disks and make changes on your computer. Virus side effects, often called the payload, are the aspect of most interest to users. Password-protecting the documents on a particular day, mailing information about the user and machine to an address somewhere are some of the harmful side effects of viruses. Various kinds of viruses include macro virus, parasitic or file virus, Boot virus,
E-mails are the biggest source of viruses. Usually they come as attachments with emails. The Internet caused the spreading of viruses around the globe. The threat level depends on the particular code used in the WebPages and the security measures taken by service providers and by you. One solution to prevent the viruses is anti-virus softwares. Anti-virus software can detect viruses, prevent access to infected files and often eliminate the infection.
Computer viruses are starting to affect mobile phones too. The virus is rare and is unlikely to cause much damage. Anti-virus experts expect that as mobile phones become more sophisticated they will be targeted by virus writers. Some firms are already working on anti-virus software for mobile phones. VBS/Timo-A, Love Bug,Timofonica,CABIR,aka ACE-? and UNAVAILABLE are some of the viruses that affect the mobile phones
2. BASIC CONCEPTS
2.1.What is a virus?
A computer virus is a computer program that can spread across computers and networks by making copies of itself, usually without the user’s knowledge. Viruses can have harmful side-effects. These can range from displaying irritating messages to deleting all the files on your computer.
2.2.Evolution of virus
In the mid-1980s Basit and Amjad Alvi of Lahore, Pakistan discovered that people were pirating their software. They responded by writing the first computer virus, a program that would put a copy of itself and a copyright message on any floppy disk copies their customers made. From these simple beginnings, an entire virus counter-culture has emerged. Today new viruses sweep the planet in hours and virus scares are major news.
How does a virus infect computers?
A virus program has to be run before it can infect your computer. Viruses have ways of making sure that this happens. They can attach themselves to other programs or hide in code that is run automatically when you open certain types of files. You might receive an infected file on a disk, in an email attachment, or in a download from the internet. As soon as you launch the file, the virus code runs. Then the virus can copy itself to other files or disks and make changes on your computer.
Who writes viruses?
Virus writers don’t gain in financial or career terms; they rarely achieve real fame; and, unlike hackers, they don’t usually target particular victims, since viruses spread too indiscriminately. Virus writers tend to be male, under 25 and single. Viruses also give their writers powers in cyberspace that they could never hope to have in the real world.
2.3.Virus side effects(Payload)
Virus side-effects are often called the payload. Viruses can disable our computer hardware, Can change the figures of an accounts spreadsheets at random, Adversely affects our email contacts and business domain, Can attack on web servers…
Messages -WM97/Jerk displays the message ‘I think (user’s name) is a big stupid jerk!’
Denying access -WM97/NightShade password-protects the current document on Friday 13th.
Data theft- Troj/LoveLet-A emails information about the user and machine to an address in the Philippines.
Corrupting data -XM/Compatable makes changes to the data in Excel spreadsheets.
Deleting data -Michelangelo overwrites parts of the hard disk on March 6th.
Disabling Hardware -CIH or Chernobyl (W95/CIH-10xx)
attempts to overwrite the BIOS on April 26th, making the machine unusable.
Crashing servers-Melissa or Explore Zip, which spread via email, can generate so much mail that servers crash.
There is a threat to confidentiality too. Melissa can forward documents, which may contain sensitive information, to anyone in your address book. Viruses can seriously damage your credibility. If you send infected documents to customers, they may refuse to do business with you or demand compensation. Sometimes you risk embarrassment as well as a damaged business reputation. WM/Polypost, for example, places copies of your documents in your name on alt.sex usenet newsgroups.
