A Crash Course in Viruses, Worms, and Other Nasty Forms of Malware

Cybersecurity talks produce a great deal of jargon. Do you know the differences between viruses, worms and malware? One of the biggest mistakes people tend to make is using the term “virus” interchangeably with malware.

To clear up any confusion, malware — short for malicious software — is a broad term that refers to any program designed to access or damage a computer system.

With that out of the way, here is a breakdown of the common types of malware you need to know in order to protect your business.


Computer viruses are the oldest forms of malware, dating back to 1971. It works by inserting copies of itself to a program, and spreads when an unwitting user launches it.

Viruses can disable your security systems, modify files, and make it difficult to connect to networks. If you experience any of these symptoms, you should install advanced antivirus software — such as ESET’s NOD32 Antivirus solution — run a full-system scan, and remove or quarantine any suspicious files.


Much like viruses, worms replicate themselves to deal much greater damage to a network; the only difference is they don’t require any human interaction to spread. If left unchecked, worms can consume large amounts of bandwidth, overload web servers, steal data, or take up storage space until computers and networks stop responding.

The ideal way to protect your system is to use a combination of firewalls and intrusion prevention systems to detect and block access to your network, and anti-malware software to eradicate any worms lying dormant in your systems.


Although it’s relatively harmless against other types of malware, adware is by far the most disruptive. It generates unwanted pop-up ads on sites you frequent, installs additional toolbars on your browser, and changes your browser’s homepage.

More malicious variations of adware, however, redirect users to malware-ridden websites. These often come with free software, making initial detection and removal especially difficult.

Avoid infection by reading installation settings carefully. If signs of adware do emerge, install and run adware-removal tools like Bitdefender as quickly as possible.

Trojan horses

A Trojan horse is a type of malware hiding as seemingly innocuous software via email. If installed, the malware creates a digital backdoor that hackers can use to remotely access the device, steal data, modify security settings, or install more dangerous malware.

Since hackers must connect remotely to your device; spikes in bandwidth consumption and network activity can give away a Trojan virus. If you notice this; disable your internet connection to prevent the malware from spreading while you attempt to locate and delete it. You can also prevent this from happening in the first place by avoiding suspicious files attachments in unsolicited emails.


Bots are programs built to perform a specific set of tasks automatically. In the wrong hands, they can be used to hijack unsecured devices, send out spam, steal sensitive data, or stage a denial-of-service attack. In 2016, bots were used to hijack internet-connected devices and overwhelm cloud services provider Dyn with service requests, causing major websites to go down.

Bot attacks can easily be avoided by password-protecting your devices, installing up-to-date firewalls and intrusion prevention systems, and running real-time threat-detection software.


Ransomware is the most notorious malware of 2017. As its name suggests, ransomware encrypts your computer and demands for ransom to decrypt them. Some attacks you’ve probably heard before may include WannaCry, Petya, and Cryptolocker.

What makes it so dangerous is that there’s usually no way to get all your files back safely, even after you’ve paid the ransom. Free decryptor tools are also available; but the best strategy is a preventive one that includes regularly updating your operating systems and backing up your files.


Unlike other types of malware, spyware is more subtle. It monitors web browsing habits, emails, and internet usage. In much more extreme cases, it tracks keystrokes to steal passwords and other personal information such as credit card numbers.

Spyware is the hardest to detect because it is set to modify security settings, evading traditional security systems. It also doesn’t directly attack your computer, which makes it even more difficult to recognise. But there are some signs you can watch out for.

For instance, random error messages or slow service could indicate that spyware is currently present in your system. You should also check whether any unusual applications are running in the background, and shut it down if possible.

Of course, like most of the malware we’ve mentioned; the best way to detect and remove spyware is by using anti-malware software.

Quickly recognising and responding to malware is important, but prevention is much better than a cure. Here at Empower IT, we provide vulnerability assessments, flexible data backup and recovery plans, plus the latest perimeter security systems to guarantee your security. Contact us today.