VIRUS (computer virus)

VIRUS (computer virus)

1. GuideThe virus requires someone to knowingly or unknowingly spread the infection without the knowledge or permission of a user or system administrator.

2. A computer virus is malicious code that replicates by copying itself to another program, computer boot sector or document and changes how a computer works.

3. A virus can be spread by opening an email attachment, clicking on an executable file, visiting an infected website or viewing an infected website advertisement. It can also be spread through infected removable storage devices, such USB drives.

4. Types of viruses

   • File infectors
     • Some file infector viruses attach themselves to program files, usually selected .com or .exe files.
   • Macro viruses
     • These viruses specifically target macro language commands in applications like Microsoft Word and other programs.
   • Overwrite viruses
     • Some viruses are designed specifically to destroy a file or application's data. After infecting a system, an overwrite virus begins overwriting files with its own code.
   • Polymorphic viruses
     • A polymorphic virus is a type of malware that has the ability to change or mutate its underlying code without changing its basic functions or features.
   • Resident viruses
     • This type of virus embeds itself in the memory of a system
   • Rootkit viruses.
     • A rootkit virus is a type of malware that installs an unauthorized rootkit on an infected system, giving attackers full control of the system with the ability to fundamentally modify or disable functions and programs
   • System or boot-record infectors
     • These viruses infect executable code found in certain system areas on a disk.

5. How to prevent computer viruses

   • Install current antivirus and antispyware software and keep it up to date. Run daily scans of antivirus software. Disable autorun to prevent viruses from propagating to any media connected to the system. Regularly patch the operating system and applications installed on the computer. Don’t click on web links sent via email. Don’t download files from the Internet or email. Install a hardware-based firewall.