Viruses vs Worms

June. 05, 2020

2:00-3:00AM PST

In order to properly thwart malware, it is essential to understand the various classifications of malware that one may encounter at some point. As intrusive software created with the goal of ensuing damage and destruction to a slew of devices, malware comes in numerous forms -- all bringing along their own problems to be addressed in varying degrees. According to PCWorld, a PC plagued by malware might exhibit symptoms that include, but are not limited to a “slower-than-usual performance, a sudden spate of pop-ups, and other anomalous issues.” However, of all of the shapes that malware can take, two are commonly confused for one another: viruses and worms. User data is precious and incredibly valuable. By creating awareness and boosting overall knowledge regarding these two different kinds of malware, we aim to help users to spot them more easily, in turn equipping them to avoid catastrophic data or IT information loss.

What is a Virus?

Although most appearances of malware are commonly assumed to be viruses, this is not an accurate categorization. As technology, and as a result, cybersecurity threat tools, have evolved and advanced, occurrences of computer viruses have become rather sparse. Today, viruses account for a mere 10% of overall malware appearances. A subcategory of malware, a computer virus is a malicious software linked to a file or document, enabling the execution of destructive code that can spread from network to network. It is crucial to note that nearly every virus is enabled as a result of its attachment to an executable file. So, following download, a virus will remain inactive until opened and in operation. In other words, when a user executes such a file, the user -- in effect -- executes the virus themselves. This malicious software is designed with the goal of bringing destruction and interference upon a system’s operations. Consequently, viruses can trigger major, catastrophic data loss and operational complications.

Despite major technological improvements made over the course of the past few decades, a virus is surprisingly still the only type of malware that can infect other files, making them incredibly difficult to eradicate. Follow this spread of infection, the virus can then transfer itself to documents, files, code, etc. located on additional devices via memory-storage devices, online systems, and networks -- often multiplying until data is obliterated or program codes become debilitated entirely. Moreover, viruses can vary greatly in their severity, with damages ranging from benign humor to immediate and total system ruin. And individuals who encounter the later may find their valuable data permanently compromised.

What is a Worm?

Similarly, a worm manifests itself as malicious software that quickly multiplies and disseminates to any, and sometimes all devices operating within the network. Differentiating themselves from viruses, worms are traditionally independent software and do not require a host program in order to circulate. In fact, absolutely no human action is needed for a worm to multiply and disperse across a number of networks, wreaking havoc. Following the infection of a device through a network connection or downloaded file, worms aggressively reproduce and spread. Easily distributing themselves across systems, worms can either take advantage of a vulnerability on a target network or weaponize a form of social engineering in order to deceive users into carrying them out. Furthermore, a worm is able to freely traverse a system by either entering a device via a fragile point or by taking advantage of file or information transport features on a device. 

According to Encyclopedia Britannica, the first worm was released onto the Internet in November 1988 from MIT, by “a computer science student at Cornell University named Robert Morris” who hoped to maintain anonymity as a guest on campus. The birth of the computer worm was rather harmless, aside from forcing nearly 1/10 of the Internet to cease operations briefly. But as time passed and technology continued to flourish, worms became a tool for cybercriminals. And very much like viruses, worms can significantly disrupt a device’s operations, bringing about disastrous levels of data loss. Self-replicating and easily-dispersed, highly evolved worms can leverage other forms of malware, like ransomware, to bring about particularly harsh attacks on their targets. Worms are frequently key elements of cybersecurity attacks, with attackers utilizing their functions to produce zombie computers that become firmly linked in botnets, all with the purpose of dispersing spam or flooding web site with blackmail schemes and other methods of denial-of-service attacks.

How Should Malware Be Addressed?

There is no one surefire method to discern whether or not a device has been plagued with malicious code. As previously mentioned, some infections that may plague devices have the potential to completely obliterate files and ultimately shut down the device. On the other hand, some infections may only mildly impair a device’s typical operations, making it immensely difficult to locate the exact root cause of malware. Individuals are advised to keep an eye out for any abnormal and peculiar device behavior. However, anti-virus software can provide users with alerts of any malicious software that has made its way onto a given device or network. And oftentimes, this anti-virus software may be able to rid a device of malicious actors all on its own. But it is crucial to keep anti-virus software as updated as possible. Cyberattackers are constantly evolving their codes and tactics in an effort to successfully debilitate victim’s devices. Malware can be costly to a user’s wallet, time, and valuable data. Strengthening a device or network’s defenses against malicious code can help to avoid any malware induced damages. Keeping software up to date, regularly changing passwords, installing and enabling a firewall, and following good network security practices are the key to protecting devices against malware in all its forms.

Utilizing an email encryption service like Trustifi that empowers users with the tools and protection necessary to avoid several kinds of malware is strongly advised. Trustifi’s advanced threat protection services serve to detect, prevent, protect against malware while supplying clients with consistent alerts of any cybersecurity vulnerabilities or malicious actors within their network.


The Editors of Encyclopaedia Britannica. “Computer Worm.” Encyclopædia Britannica,

Encyclopædia Britannica, Inc., 10 Nov. 2017,

Geier, Eric, and Josh Norem. “How to Remove Malware from Your Windows PC.” PCWorld,

PCWorld, 6 May 2019,

Try Trustifi Today

For Individuals

Our Free Trial Is Forever Free

For Business

See if Trustifi Is Right for Your Organization