Definition of viruses


  • 1 malicious programs
    • 1.1 The virus
    • 1.2 Types of viruses
    • 1.3 Spyware
    • 1.4 Monitor the keyboard
  • 2 Anti-virus software
  • 3 of the most dangerous viruses throughout history
    • 3.1 Chernobyl virus
    • 3.2 Melissa worm
    • 3.3 Stuxnet worm
    • 3.4 The Wanakrai Ransom Program
  • 4 References

Malicious programs

Malware is any program that causes certain harm to a computer user, and viruses are included under it (English: Viruses), which are the most common types of malware, in addition to a computer worm (English: Worm) and Trojans (English: Trojan Horses), spyware (ransomware), which infects computers and encrypts all data on it, and other malicious software. [1]

Malicious software developers aim to spread their programs across devices and networks with all available means, so the program can be transmitted through the Internet by downloading them to the user's device without his knowledge or permission, or by visiting the user for false websites , or opening it to emails containing viruses Also, these programs can be transmitted to the system through flash memories (in English: USB Flash Drive), in addition to many other means. [1]

The virus

A computer virus is a malicious program that multiplies in the target device by copying itself in other programs, in the boot sector, or even in documentary files, and this is done without the knowledge or permission of the computer user; A person has started spreading the virus to the machine, and this person may be so ignorant of it that it spreads the virus unaware. The virus may spread in several ways, this can be done by opening the user to an email message containing viruses, or running a specific program, or visiting a site, or even through removable storage such as flash memory, or otherwise. [2]

The virus changes the mechanism of the computer's work, so its effect on the infected device may be by deleting or encrypting the data and files on the device, copying it, affecting other programs, or modifying the system software or disabling it from working. Many viruses are distinguished by being able to avoid anti-virus software (English: Anti-Virus Software), so it is difficult to detect it. [2]

Types of viruses

There are many types of viruses that differ in their impact on the infected machine, including the following: [2]
  • Viruses that infect files. This type associates itself with programs, usually with the extension "EXE." Or "COM.".
  • Transformed viruses (English: Polymorphic viruses). This type of virus has the ability to change its code without changing its mechanism of action to avoid detection by anti-virus software, especially those that rely on virus detection by fingerprint analysis.
  • Resident viruses, which store and hide themselves in the system's RAM, so the virus can infect new files and other new programs even if the original file of the virus is deleted. This type of virus usually starts when the operating system (English: operating system) of a program is activated or a specific action is started.
  • Rootkit viruses; they install Rootkit viruses (programs that allow the execution and activation of administrative commands on a computer) on the target machine, so you can modify or disable system programs or functions. This type of virus is able to avoid most anti-virus programs, especially those that lack a scan on the rootkit programs on the device.
  • Viruses that affect the boot sector, this type of virus installs itself in certain places on the hard disk or flash memory (in English: USB flash drive) so that it starts operating immediately after activating these devices.

Spying programs

Spyware is installed on the target device for the purpose of spying, violating its privacy and exploiting it. These programs may be used for purposes that are not harmful to the user, such as installing their parents on their children's devices to expose their activities on the Internet , or by companies on employees ’devices to make sure of the sites they browse during work, etc. [3]

Keyboard monitor

The keyboard monitor (English: Keylogger) stores everything a computer user writes on his computer using the keyboard in addition to his overall activity, and the keyboard monitor may be either a program or a device that connects to the computer. The keyboard monitor can be used either for harmful purposes, such as stealing information from passwords or credit card numbers, or for useful purposes such as solving computer problems by technicians and parents following up on their children's activities, [4]Other than the ability of the keyboard monitor to steal passwords, some of them are also able to photograph the computer screen, in addition to saving copies of e-mail, spying on conversations that took place on the device, knowing the sites the user visited, recording the names of the programs that he also ran, and sending all the information Captured by a designated server or computer, either by e-mail or by using one of the file transfer protocols on the Internet. [4]

Anti-virus program

Antivirus program: It is a program that has the ability to detect, prevent, and disable malicious programs that may infect computers. [5]

One of the most dangerous viruses in history

Chernobyl virus

Chernobyl virus (English: CIH Virus), a virus that spread in 1998 AD, and was doing sabotage every year that commemorates the anniversary of the explosion of the nuclear reactor in Russia; A chip installed on the motherboard (English: Motherboard), which prevents the computer from working until the motherboard is replaced. [6]

Melissa worm

Melissa Worm spread (1999: Melissa Worm) and led to millions of dollars in losses. The virus was spread by e-mail , through a fake e-mail that sends itself to 50 other e-mails when opened. [6]

Stuxnet worm

Stuxnet worm spread (in English: Stuxnet Worm) in 2010, and it was spread via USB drives when connected to a computer , and it did not require an internet connection to be able to spread. The virus infected nuclear power plants in addition to uranium enrichment plants in Iran. [6]

Wanakrai Ransom Program

The WannaCry Ransomware virus spread in 2017 and infected more than 100,000 organizations in more than 150 countries, including major companies as well as government departments. The virus was spread by e-mail and exploited a vulnerability in Windows operating systems (English: Windows), and the virus had infected 16 hospitals in the United Kingdom. [6]