COMPUTER VIRUSES are small software programs designed to spread from one computer to another and interfere with computer operation.
It attaches itself to the target computer operating system and automatically replicates itself to spread to other computers.
Viruses come in thousands of types and versions with new ones being invented every day, each requiring a different antivirus.
Viruses are harmless diversions, most are malicious and cause widespread and severe damage, and may bring down entire communication networks and websites.
Viruses have the least impact on a computer and can be easily removed by antivirus programs.
Viruses immediately active, others remain latent for weeks or months or work slowly to avoid detection and cause destruction over long periods. propagation of computer viruses is a crime in many countries.
What Are The Reasons for creating viruses?
- To control or hack a computer and use it for specific tasks.
- To bring money by using such malware as a cash machine.
- To steal sensitive information.
- To prove that they are capable of writing a virus.
- To offense against a company.
- To cripple a computer or network.
Top 10 Computer viruses
BOOT SECTOR VIRUS
BOOT sector virus is a type of virus that infects computer systems by copying code either to the boot sector of the hard disk or the partial table on a floppy disk.
During startup, the virus is loaded into the memory. Once in memory, the virus will infect any non-infected disks accessed by the system.
EXAMPLE: Parity BOOT, disk killer, and stoned.
PROGRAM FILE VIRUS
Program file virus is a type of virus that can travel on media like a DVD, Pen drive, or across the internet by an e-mail attachment. A computer virus designed to infect executable program files having extensions .exe, com.
These viruses infect executable files or programs such as those with extensions like .com, Macintosh, Unix, Dos, Windows.exe, .ovl, etc.
Sunday and cascade are examples of this virus.
A macro virus is a computer virus that “infects” a Microsoft Word or similar application and causes a sequence of actions to be performed automatically when the application is started.
Macro viruses tend to be surprising but relatively harmless. A typical effect is the undesired insertion of some comic text at certain points when writing a line.
A macro virus is often spread as an e-mail virus. A well-known example of the macro virus is the Melissa virus.
Viruses are very infections that can perform different actions on an infected computer.
These types of viruses may infect both the executable program files and the boot sector.
In computer, if you clean the program files the virus remains in the boot sector. It gets activated again when the computer is opened.
Resident viruses install themselves directly into the primary memory of your system.
That virus can execute anytime when an operating system loads and corrupt files and programs on your computer system.
These types of computer viruses are hard to find and it is even harder to remove them.
For example, CMJ, Meve, and Randex are popular examples of resident viruses.
It can infect the content of a file.
These types of viruses can infect both standalone files as well as entire pieces of software, losing the original content.
The overwrite virus is usually spread through email and is hard to identify.
If you want away from the virus you have to delete the infected files to remove the virus from your computer.
Space filler virus
The space filler viruses fill empty spaces between the codes without damaging the code or increasing its size.
These viruses usually attach themselves to the file and try to alter the execution of the program.
These viruses change the encrypted code.
A polymorphic virus is a computer virus that is capable of mutating itself when it replicates, making it more difficult to identify with ordinary antivirus software.
To effectively find such viruses, antivirus software needs to have more complex algorithms available to help it identify distinctive patterns. Which can betray the presence of a virus even when the code behind the virus is not known to the software.
The examples of polymorphic viruses are involuntary, stimulate, cascade, Phoneix, and Evil.
Stealth viruses are complex malware that hides after infecting a computer.
Once hidden, it copies information from uninfected data onto itself and relays this to antivirus software during a scan.
This makes it a difficult type of virus to detect and delete.
Stealth viruses hide altered computer data and other harmful control functions in system memory and self-copy to undetectable computer areas.
In order to avoid detection stealth viruses also self modify like, code modification.
The stealth virus changes the code and virus signature of each infected file.
Frodo, whale, are examples of stealth viruses.
Direct action virus
Direct action viruses attack on .exe and .com files.The virus is known as a non-resident because it does not install itself.
Direct action viruses get activated when you execute the file containing the virus.
Otherwise, the purpose of this kind of virus is to replicate and infect files in folders.
Having some limitations of a direct action computer virus, it does not typically delete files or affect the performance of the computer system.
Aside from some files become inaccessible.
Symptoms of Computer virus
- Deleting files from the computer.
- Reformatting the hard disk.
- Hanging of the system.
- Displaying unusual messages.
- Displaying strange pictures on the screen.
- Decreasing the memory of the computer.
Preventive measures of the Computer viruses
- Always use an antivirus software program.
- Update the virus database in your antivirus program regularly.
- Do not use pirated software.
- Take the backup of important files.
What Are Antivirus Programs?
A program designed to detect and remove viruses from the infected programs or files in the computer system.
Antivirus (or anti-virus) software is used to safeguard a computer from malware, including computer viruses, computer worms, and Trojan horses.
Antivirus software may also remove or prevent spyware, along with other forms of malicious programs.
Antivirus is a computer program that is designed to identify, prevent and remove viruses from a computer.
Free antivirus software generally only searches your computer using signature-based detection which involves looking for patterns of data that are known to be related to already identified malware.
Conclusion on Computer Virus
A computer virus is one of the major problems of computer users. It is a very destructive program that can be devastating to companies and individuals. letting the virus in it can cause harm or even destroy all files stored in the computer.
If you want to know more about computer virus watch videos
What is Computer Virus and types?
A computer virus is a type of malware that transfers or inserts its virus code to multiply itself by altering the programs and applications. The computer is infected through the replication of malicious code. Computer viruses came in different ways and forms to infect the system in different ways. … Boot Sector Virus.
What is an Antivirus example?
Examples of common antivirus programs include Norton Antivirus, Kaspersky Anti-Virus, and ZoneAlarm Antivirus.
How do you tell that your computer has been infected with a virus?
If you have noticed any of the following issues or problems with your computer, it may be infected with a virus:
Slow computer performance and taking a long time to start up or open programs.
Problems shutting down or restarting.
Frequent system crashes and/or error messages.
Unexpected pop-up windows.
How can I clean my laptop from viruses?
If your PC or laptop has a virus, following the following simple steps to remove the virus from the laptop.
Download and install a virus scanner.
Disconnect from the internet.
Reboot your computer into safe mode.
Delete any temporary files. …
Run a virus scan.
Delete or quarantine the virus.
Reboot your computer.
What are three examples of antivirus?
The best antivirus software of 2021
Bitdefender Antivirus Plus. Well-rounded everyday antivirus protection. …
Norton AntiVirus Plus. Smooth protection for your system. …
Avira Antivirus Pro. …
F-Secure Antivirus SAFE. …
Kaspersky Anti-Virus. …
Trend Micro Antivirus+ Security. …
Webroot SecureAnywhere AntiVirus. …
ESET NOD32 Antivirus.