What is Malicious Code?


By DeVry University

September 2, 2022
5 min read

Malicious code is a broad category of dangerous programs, files and code strings that are used to create malware and carry out a cyberattack. There are several different types of malicious code, each with different effects, uses and methods of attack.

Malicious code can include everything from a full software programs like keyloggers or spyware, to small viruses that prevent your computer from functioning correctly. And much like there are many different types of malicious code, there are different levels of damage that it can cause.

Therefore, it’s important that you understand what malicious code is, some of its different forms, and how to defend against attacks that could threaten your devices and data.

In this article, we’ll explore these things in the following sections:

How Does Malicious Code Work?

Malicious code can pose a wide range of threats to your computer. Malicious code works by infecting your computer with unwanted files, programs or lines of code that can impede its ability to function. It can also steal your data or carry out commands without your permission.

Malicious code can also lock down your computer, or otherwise impact its ability to work properly. Chances are that you’ve used a computer infected by one of these viruses and have firsthand experience with the frustration that they can cause. While this type of malicious code is nowhere near as dangerous as others, when installed on multiple computers in an organization, it can have meaningful impacts on productivity and output.

One of the most dangerous purposes of malicious code is to steal sensitive data, such as your bank password or other information. This information can then be used to steal your identify and wreak havoc on your personal and financial life.

But cybercriminals do not limit their targets to individuals, the impact of cyberattacks may be even worse when companies, who often hold great amounts of data, come under threat. Malicious code can be used to break into organization’s databases, crash company servers and steal data from countless customers.

Different Types of Malicious Code

The sheer volume of malicious code types available for use makes it even more important to understand how each type works and how you and cyber security professionals go about putting in safeguards to protect sensitive information.

Here are a few of the more well-known types of malicious code and what they do:

  • Keyloggers: Keyloggers track your keystrokes when you’re typing your passwords or other sensitive data into third party website to steal information or gain access.
  • Spyware: Spyware infects your computer by searching your files for sensitive data and covertly transferring it.
  • Trojan horses: Trojan horses pose as legitimate software in order to trick you into installing malicious software.
  • Adware: Adware displays unwanted ads on your screen.
  • Ransomware: Ransomware seizes your personal files and encrypts them before demanding payment to retrieve them.
  • Rootkits: Rootkits provide unknown users access to your device without being detected.
  • Worm viruses: Worm viruses replicate themselves within your device, and then spread to others on the same network.

How Widespread is Malicious Code?

According to Av-Test.org, there are currently more than 1 billion pieces of malware installed around the world. 

In a 2019 article, Av-Test.org outlined the places malicious code is likely to pop up, including in dangerous URLs, PUAs (potentially unwanted applications) and inadequate security levels for connected smart devices. This connectivity, they explain, can create a gateway for bad actors to walk through, taking advantage of the way IoT-connected devices communicate with each other to gain access much more easily.

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How to Combat Malicious Code

Even if you’re not a cyber security professional, there are plenty of steps that you can take to help keep yourself safe from malicious code while you’re online, including:

  • Only download files from places you recognize and trust.
  • Double-check the URL before clicking on anything from a website.
  • Keep your operating system (OS) and antivirus software up to date.
  • Enable two-factor authentication whenever possible.
  • Only download applications from your phone’s official app market.
  • Install an ad- or pop-up blocker to your browser.

If you still end up downloading something with malicious code, there’s no need to panic. Immediately disconnect the infected device from the internet, then search through all your files for anything that looks unfamiliar and delete them immediately. If you’re not sure what you’re looking for, you may want to run an antivirus scan to identify and remove any malicious codes or software for you.

If you’re still in doubt, reach out to a computer specialist to make sure the malicious code is removed from your device.

Want to Learn How to Defend Against Cyberattacks?

If you’re interested in making a career out of defending devices and networks against malicious code, DeVry’s cyber security degree programs can help you get started. We offer three different programs to help you focus your interests while preparing to pursue a career in cyber security, including our Undergraduate Certificate in Cyber Security, our Bachelor’s Degree in Information Technology with a Cyber Security Specialization and our Bachelor’s Degree in Computer Information Systems with a Cyber Security Programming Specialization. Classes start every 8 weeks.

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