What are the 3 types of Computer Viruses?
You might compare a computer virus to a biological virus. Once they find a host, they can spread disease. Both types of viruses take advantage of weakened services that don’t have computer virus protection services. The best way to fight them is to build resilience with cyber security services.
A short history of computer viruses
It’s important to learn history, so you aren’t doomed to repeat it. Recognizing modern threats becomes easier when you understand background and context. The first computer virus was created by Hungarian scientist John von Neumann after he published the “Theory of self-reproducing automata.” It wasn’t a functioning virus, but he theorized that computers would start to mirror the human nervous system. Moreover, as computers became more complex, they could then self-replicate. While Neumann did not call it a virus, he did describe the automated and self-sustaining nature effectively.
Fast forward to 1971 for the world’s first computer virus, the Creeper. Bob Thomas, who worked at BBN Technologies, developed the virus when he was demonstrating mobile applications. An infected computer would display the following text, "I'M THE CREEPER : CATCH ME IF YOU CAN.” While the Creeper virus did not cause systemic damage, it did scan if there was another computer it could infest and it would hop over. Thomas’s colleague Ray Tomlnson updated Creeper to move automatically and self-replicate leaving a copy on each computer before heading for the next one. Ray also created the Reaper, which was designed to find any computer infected by the Creeper. As a result, the Reaper is considered the first anti-virus solution.
However, the Creeper and the Reaper were self-contained within the internal BBN network. Yet, the Elk Cloner was not as it attacked Apple II computers. The only way to catch the Elk Cloner was to insert an infected floppy disk, which usually had a game on it. The Elk Cloner would infect the Apple II computer and any other floppy disks inserted into the computer ensuring its spread. After you booted the infected game 50 times, your screen would display this message,
“Elk Cloner: The program with a personality
It will get on all your disks
It will infiltrate your chips
Yes, it's Cloner!
It will stick to you like glue
It will modify RAM too
Send in the Cloner!”
It seems scary, and it did scare folks at the time. But, it was created as a prank by then-15-year-old Rich Skrenta. Fortunately, if you rebooted the computer, the virus would be gone.
In 1983, Fred Cohen coined the term “computer virus” when he published his academic paper “Computer Viruses -- Theory and Experiments.” Cohen depicted a computer virus “a program that can 'infect' other programs by changing them and evolving. A virus can then spread through a computer system or network using end-user authorizations. Every infected program also acts as a virus.
In 1986, the first computer virus came to fruition called “Brain.” It infected Windows PCs, and it did take up a lot of memory while slowing down floppy disks. The creators could use Brain to track infected devices. Brain did take advantage of an exploit in the Microsoft OS. Nonetheless, it was not designed to be a virus. It was created by Basit Farooq Alvi and Amjad Farooq Alvi who designed it to protect their medical software. In the code, they left their addresses and phone number so they could remedy infected machines. Unfortunately, the floppy disk it came on was stolen so often, they were overwhelmed with fix requests.
What is the difference between a virus and a worm?
Viruses and worms are different where viruses are triggered by their host’s activation. On the other hand, worms are malicious programs that can breach a system then self-replicate and propagate independently. Worms do not require activation or human intervention.
Typically, viruses are attached to shared or downloaded executable files with a program that runs script. Viruses can also attach to a non-executable file such as an image or Word document. When the host file is accepted into the target system, it runs once the host file is activated. Once activated, the virus can execute malicious code and infect other system files. However, worms don’t require activation. Worms can enter a system as a downloaded file or through a network connection. Worms can also run, self-replicate, and propagate without any triggers.
The three types of computer viruses
Currently, experts have identified three major types of viruses, which can be further divided into subcategories. They include:
Macro viruses – The largest of the three virus types, macro viruses use built-in programming scripts that are found in Excel or Word to automate tasks. When an unsuspecting end-user opens the infected document, it multiplies by making copies of itself.
Boot record infectors – Boot viruses, or system viruses, attack programs found on floppy and hard disks. Each time an end-user boots up, the virus will run automatically. Hackers can gain full access to an entire system to do what they one. Boot record infectors can spread to every infected bootable disk.
File infectors – These types of viruses are designed to locate and modify .EXE or .COM files. Each time an end-user runs a compromised program, the file infectors activate. Unfortunately, file infectors can also stay inactive in the system memory until activation. In addition, file infectors are transmitted over networks.
The future of computer viruses
To date, computer viruses have been around for over 60 years. What was once self-contained and harmless has quickly escalated to cyber crime. Viruses are evolving. Threat actors are using more sophisticated techniques to create new methods of infection. If you want an example of what is to come, study the Trojan virus -- it is difficult to detect, challenging to remove, and circumvents many cyber defenses. Invariably, every organization should invest in computer virus protection services.
The experts at SSI specialize in virus mitigation. When you need fast, efficient virus elimination, contact us.