You can call a malicious computer code a computer virus. It is also designed to self-copy, spread from device to device, and either damage the devices or steal data. Compare a computer virus to a biological virus that makes you ill. It is persistent and prevents normal functioning. Further, it requires a powerful and proactive response to eliminate it. Yet, many organizations are ill-prepared for the onslaught of computer viruses targeting systems everyday.

A computer virus operates similarly. It replicates consistently and finds its way into your programs and files to the extent where they can stop working altogether.

How does a computer virus cause extensive damage?

Some viruses will reformat your hard drive, delete files, and even damage programs. Some may flood your network with traffic so you can’t execute any Internet activity. Others may disrupt your systems, cause computer crashes, or sap your device memory.

ZueS is one example of a computer virus that distributed ransomware via peer-to-peer download sites. It then committed banking fraud. Today, there are thousands of computer viruses on the Internet waiting for their next victims.

Even if you are extremely cautious, you can accumulate computer viruses through the following ways:

  • Visiting an infected website
  • Opening spam email or an email attachment
  • Sharing music, files, or photos
  • Installing mainstream software applications before reading their license agreements
  • Downloading free games, toolbars, media players and other utilities

In what ways can a computer virus spread?

Networks, external devices, email attachments, and social media messages have all been used to spread computer viruses. In the early days, computer viruses were only spread through floppy disks. Today, mobile devices are particularly vulnerable because opening links is so convenient and straightforward, it takes no time. Often, the end user has to click on a link or open an infected attachment to enable the computer virus. Therefore, the most common form of spreading computer viruses is by email attachments. Although, SMS text messages are becoming more prominent since everyone texts as a form of communication.

How can you tell your systems are infected with a computer virus?

Computer virus symptoms are easy to tell, and they include:

  • Slow computer performance
  • Unusual computer behavior
  • Unaccounted data loss
  • Computer crashes

What are the types of computer viruses?

The first-ever computer virus was created by Bob Thomas of BBN Technologies in 1971, and it was called Creeper. It was both self-replicating and experimental. Computer viruses have come a long way since then. Below is a list of the most common forms.

Directory virus

Also known as the Cluster Virus, this computer virus changes your DOS directory by having it point to the virus code instead of the intended program. So, DOS will load and execute the virus code before running your original program. And it becomes increasingly difficult to determine the initial infection point. A directory virus can also infect every program in your directory.

Boot Sector virus

As the name implies, the Boot Sector virus will impact your storage device’s master boot record (MBR), even if it is not bootable. This virus injects its code into your hard disk’s partition table to get into the main memory once your computer restarts. If you notice booting issues, lack of a hard disk, or unstable system performance, these may be signs of a Boot Sector virus. Once it gets into a device’s main memory, it can impact any file.

FAT virus

The file allocation table or FAT, is the component of a storage disk used to store information such as total capacity, location files, and available space. So, the FAT virus makes it virtually impossible to allocate these types of files, and you may have to reformat the entire disk. A FAT virus can affect any file.

Companion virus

Companion viruses were prevalent during the MS-DOS age and can impact every .exe file. They do not change existing files, but they create copies of files with a different extension such as .com that runs simultaneously with the original program. For instance, if there is a file named butter.exe, the Companion virus will create a hidden file named When the system calls the “butter” file, it will prioritize over butter.exe. Further, the Companion virus can delete original files.

Web scripting virus

A web scripting virus can impact any web page because it injects hidden code into the footer, header, or root access file. So, it lets attackers inject client-side scripting within a web page. Web scripting viruses are used to attack emails, social network sites, and even user review sites. They can also send large amounts of spam and damage server files permanently.

Direct Action virus

A Direct Action virus can negatively impact every .exe and .com file extension. It is designed to embed into the main memory and infects all programs defined within the Autoexec.bat path. Next, it deletes itself. It can also destroy files within USBs. While a Direct Action virus may not delete system files, it does change their performance.

Overwrite virus

The Overwrite virus is extremely dangerous and can affect any file. They can also impact operating systems such as DOS, Mac, Linux, Windows, and more. They delete data while replacing original code with its own. If your original program stops working, then it’s possible you have the Overwrite virus. Unfortunately, once data is infected, you can’t restore it.

Memory Resident virus

The Memory Resident virus is activated every time you turn on your computer. Further, it impacts every file running on your desktop by running its own code before any program is fully executed. It also blocks original scripts from running.

Polymorphic virus

It’s very difficult to locate a Polymorphic virus because it encodes itself using various algorithms and encryption keys with every program infection it creates. Hence, this virus is designed to avoid detection.

Multipartite virus

Once a Multipartite virus infects and spreads, it will stay in the memory. However, it modifies the content of your applications. It also impacts every file and the boot sector. Symptoms of a Multipartite virus include low virtual memory and performance lag.

Macro virus

The Macro virus may affect .Doc, .XLs, .mdb, and .PPS files. Since the virus is written in the macro language, it may start to fun once you open a document. The Macro virus is typically shared through email.

Don’t forget these other dangerous forms of malware that are just as nefarious as computer viruses:

Logic Bombs

Frequently, a logic bomb is a code hidden within a software tool. It also acts like a worm. To illustrate, a web browser extension may have a Keylogger code embedded inside. When you visit the login page, the code is activated and captures all your keystrokes.


A worm is a type of malware that relies on emails or system vulnerabilities to spread. However, it can overload your network by overusing the bandwidth, which then drives a server failure or shut down.

Trojan Horse

A Trojan Horse is designed to look authentic. Unlike a computer virus, it is non-replication. End users are often tricked into loading it onto their systems. Once loaded, it can give cyber criminals remote access to your devices, crash your computers, destroy files, alter the registry, and more.

Does Citrix protect against computer viruses?

Citrix offers virtualization capabilities for organizations to consistently deliver hosted resources and applications to their intended end users. In addition, Citrix uses application delivery and security solutions that are based on WAN edge features. Therefore, users can expect visibility into every app and their network conditions to ensure consistent cyber security of the entire network. As such, it does protect against computer viruses.

For example, Citrix ADC can simplify the process of optimizing cloud-based, SaaS, and on-premises applications. It is centrally managed so that you gain multi-cloud and multi-network visibility. Moreover, Citrix SD-WAN can identify over 4,500 apps at any time and automate network conditions to prevent disruption. By using advanced WAN edge features, it uses a zero-trust policy that does not impact network performance.

So, Citrix helps to prevent computer viruses because it ensures consistent policies are always in place before any application is deployed. How? Well Citrix ADC form factors are designed to ensure a continuous security policy across every application and API, and throughout every cloud environment by sharing a single code base. Thus, it mitigates complexity and the potential for vulnerabilities. The same is true whether you use monolithic or microservice-based apps.

The protection is layered with an integrated web application firewall (WAF), bot management, and volumetric distributed denial of service (DDoS) protection. Citrix also provides an API security gateway for enhanced authentication. As a result, your application delivery system is safer.

In Conclusion

It’s certainly vital to protect your computers and devices against computer viruses. There are too many to keep up with, and more created and deployed every day. Peace of mind, and safe systems are vital. With SSI, you can use managed Citrix services to elevate your employee and customer experience by deploying an essential and secure delivery solution.