What Are Computer Viruses & What Damage Do They Cause?
Computer viruses have been crawling around the internet for decades, continually evolving and adapting to creep their way past the latest security measures. If you’re lucky enough to have never encountered a computer virus (or even if you have), you might not understand exactly what they are or how they work. Let’s take a look at what exactly computer viruses are, the different types of computer viruses, how they can affect your computer and how they spread.
What are computer viruses?
A computer virus is a type of malicious software, also known as malware, that – similarly to a biological virus – infects and replicates itself on a host system. Viruses can cause damage to files, programs, and the overall functionality of your computer. Once installed, a virus can spread itself to other files or even to other systems, depending on its capabilities. Viruses are often hidden within legitimate files or programs, making them difficult for users to detect without the help of antivirus software – or prior experience with the damage they cause.
How do computer viruses work?
Similarly to biological viruses, computer viruses need some sort of human intervention in order to spread – they can’t get into your devices on their own. This commonly happens when an infected file is opened or downloaded. Once triggered, the virus will begin to execute its code, embedding itself in other files, programs, or areas of the system. This process allows the virus to spread from one file to another – it could also spread to other computers, by sending compromised emails and messages to your friends, family or colleagues.
Viruses can be everything from a simple annoyance to a cause of major, sometimes irreparable damage. They impact individuals, organizations, and even infrastructure.
Types of computer viruses
Different types of computer viruses can operate in different ways. Let’s take a look at some of the different viruses you might encounter, and the range of damage they can cause.
Boot sector viruses
A boot sector virus targets the master boot record (MBR) of a hard drive or removable storage (such as an external hard drive). The MBR is crucial because it’s the part of the drive that allows the operating system to load. In this way, a boot sector virus can prevent a computer from starting correctly – or, at all.
In the past, boot sector viruses were spread through floppy disks, but today they can be transferred via USB. They have become less common as technology has advanced, but can still pose a serious threat because of the way in which they attack the start-up functions of a computer – this makes them harder to remove.
File infector viruses
As the name suggests, file infector viruses attach themselves to files. Every time the infected file is opened, the virus is activated. This type of virus can corrupt and damage files, resulting in data loss that can range from frustrating to catastrophic. Recovery might only be possible through professional intervention.
Macro viruses
Macro viruses target files created in applications that use macros – like Microsoft Word or Excel. The virus spreads by embedding malicious code within these files, which is then activated when the file is opened. The virus can then send itself to other systems via email, making it particularly dangerous to corporate email systems.
How do computer viruses spread?
We’ve already mentioned some of the ways in which viruses can spread and replicate themselves – but here are the ways in which the average user is most likely to come across a virus.
Email attachments and links
One of the most common ways viruses spread is through email attachments or links. A user might receive an email that appears legitimate, prompting them to open an attached file or click on a link. The attachment might look innocent – an invoice, a document, or even a message from a friend. However, once opened, the attachment or link will activate the virus.
Phishing schemes use this approach with great success. These schemes are specifically engineered to trick users into downloading malware, and their levels of deception are growing more advanced as time goes by.
Downloading infected software
Infected downloads are another popular method of spreading viruses. Users might unknowingly download a virus along with software or files – this commonly happens with sites offering free or pirated media. Sometimes, even legitimate-looking websites can host infected files, especially if they don’t vet user-uploaded content or ads.
Hackers are smart, and will do everything they can to make their offerings appear legitimate and enticing. This includes mimicking popular software.
Removable media
We’ve already mentioned how floppy disks and USB drives can be used to carry viruses between systems. While this might seem like a dated approach to some users, removable media is still widely used in certain industries, and if these devices aren’t properly scanned they can introduce malware to secure networks, potentially leading to serious security breaches.
What damage can computer viruses cause?
We’ve mentioned how computer virus damage can range from irritating to irreparable, but what exactly does that mean for users?
Data corruption and loss
One of the most damaging effects of a computer virus is data corruption or loss. Some viruses are designed to delete, modify or corrupt computer files, causing irreversible damage. In worst-case scenarios, entire hard drives can be wiped or overwritten, leaving users with no way to recover their data.
In ransomware attacks, viruses encrypt files on the infected system and demand a ransom for the decryption key. If the ransom isn’t paid, the user may lose access to their files permanently, often leading to significant personal or financial losses.
System performance issues
While at work on your computer, viruses consume system resources. This can slow performance, causing programs to freeze or crash, and potentially rendering the computer unusable.
Security breaches
Some viruses are specifically designed for spying and theft, resulting in serious security breaches. Once on a system, these viruses may monitor keystrokes, capture screenshots, or access files to steal sensitive information such as login details or financial data. This stolen information might then be sold on, used in identity theft schemes, or as part of corporate espionage.
Stay informed, not infected
Prevention is always better than the cure when it comes to viruses – this is why understanding how the different types of computer viruses work and spread is crucial to keeping your data and personal information safe. By staying informed and vigilant, you can reduce the risk of falling victim to viruses looking to worm their way into your devices. Using antivirus software such as SUPERAntiSpyware can help to bolster your defenses and share the responsibility of keeping you safe.