A computer virus has the potential of shutting you down and completely wrecking your business. While some may at best be a nuisance, others are a potential disaster waiting for the right triggers to cause havoc.
Since the first virus, Elk Cloner, that targeted floppy discs, computer viruses have evolved to become, perhaps, one of the greatest threats of the 21st century. This is because businesses, governments, and even personal and public lifestyles have become extremely wired to the extent that almost every transaction or engagement is conducted via the internet.
As such, any virus that threatens the stability of the internet has the potential of bringing global affairs and engagements to a standstill. Below are some of the most dangerous types of computer viruses:
1. Boot Sector Virus
A boot sector virus poses one of the greatest threats to a user. These sneaky parasites infect your master boot record and are extremely difficult to purge. In most cases, to clean a boot sector virus, you will have to do a full system format. This is unavoidable, notably if the virus encrypts your boot sector or damages the code irretrievably.
Boot sector viruses are mostly spread through removable media. They were extremely common in the 1990s when using floppy diskettes defined the life of a computer geek.
However, they were also notorious for infecting USB drives and email attachments. Due to developments in the architecture of BIOS, their prevalence has dramatically come down in the last decade.
2. Multipartite Virus
This virus is hazardous for one simple reason: unlike other viruses that target one method of infection, multipartite viruses come out guns blazing in all directions. This multi-pronged attack on your system means your system is compromised from a variety of angles.
As such, removing it requires different actions that target the infected areas. A multipartite virus can infect your executable files and the boot sector simultaneously, which makes it easy for the infection to spread rapidly.
Cleaning these types of computer virus means removing it from both the program files and the boot sector. This is because even if you purge your program files and fail to remove it from the boot sector, it is immediately reproduced the moment you reboot your computer.
3. Overwrite Virus
This virus can be extremely frustrating to an end-user, although it does not pose a significant danger to your entire system. It deletes contents of infected files and can only be purged by removing the whole record, which means you will end up losing that file’s contents.
It is known to infect an entire software or individual files. An overwriting virus is hardly detectable and can spread through email, which makes it difficult for the average computer to detect. Although they were quite rampant with Windows NT and Windows 2000 in the 2000s, they are still lurking out there, waiting for vulnerable systems to infect.
4. Direct Action Virus
This type of virus is one of two that affect files. It is known as a “non-resident” virus because it does not install itself or hide in the memory of your computer. It inflicts damage by attaching itself to a file type; for instance, COM or EXE files.
As long as it is dormant, it is basically harmless. The real threat occurs when someone executes it. When this happens, the virus comes alive and starts searching for similar files in your computer directory to infect. Before you know it, most of your essential data could be affected. The only reprieve, however, is that it does not usually ground your system’s performance, nor does it delete your files.
However, it makes some of your files inaccessible; otherwise, it has little impact on a user. Besides, you can quickly purge it using anti-virus software and IT software solutions that specialize in eliminating these viruses.
5. Resident Virus
A resident virus is the other type that infects files. However, the difference between this virus and the direct action is that it installs itself on your computer. What makes this virus more dangerous than the direct action one is that it continues to spread even after you have removed the initial source of infection.
These types of computer virus attacks are incredibly sneaky and hard to spot. They are also challenging to purge. A resident virus comes in two variants: slow and fast infectors. The goal of fast infectors is to cause the most damage as fast as possible and are therefore easy to spot.
The slow infectors, however, are extremely dangerous since they infect your system slowly, which means you hardly notice them as they systematically affect your system. They can, in extreme cases, infect your anti-virus software to the extent of infecting every file scanned.
6. Spacefiller Virus
If there is a dangerous type of computer virus, it is the spacefiller. What makes this virus menacing is that it does not behave like the other viruses that seek to attach themselves to files. Instead, it sneaks into an empty space that can sometimes exist in a file.
Since it occupies empty spaces, it can infect a program without affecting its size or causing damage to the code. This way, even the most sophisticated anti-viruses are unable to detect it. Also referred to as “Cavity Viruses,” this stealth spacefiller virus is not common but could become common courtesy of the resurgence of Windows-based portable executable files.