The Basics of Malware and Spyware

Malware and Spyware
Malware and Spyware

Malware, short for malicious software, is designed to harm devices, networks, and end users. It can steal or encrypt data, alter or hijack core computer functions, and spy on end users without their knowledge or permission.

Cyber threats can penetrate your device when you visit a hacked website, download infected files, install programs or apps from unfamiliar providers, click on suspicious emails or text messages, or have a less than robust cyber defense solution.


Like flu viruses, computer viruses infect people by attaching to healthy cells and causing damage. Viruses can do all sorts of harm, from corrupting files to destroying systems and networks.

Viruses are self-replicating, allowing them to spread to multiple computers without human intervention. They work by piggybacking on to existing programs or replacing them with copies of themselves. They typically go unnoticed until they reach a specific size and start running in the background, consuming system resources and spreading.

Computer worms operate similarly, though they don’t need to attach to programs to spread. They exploit security vulnerabilities to automatically replicate themselves across multiple systems, draining network and system resources. They can also encrypt data and hijack core computer functions, stealing sensitive information or demanding ransom for its return.

Trojans, RATs, and rootkits are other dangerous malware types. Trojans often represent themselves as legitimate programs, while RATs gain privileged access to your system. On the other hand, rootkits hide within your operating system and give attackers complete control over the device. These tools are hazardous for jailbroken mobile devices, as they can bypass the operating system’s built-in security measures. Regardless of the type of malware, cybercriminals are constantly developing new ways to infiltrate your systems and steal or alter your personal and organizational data. Like a game of whack-a-mole, when you think you’ve got one threat neutralized, another emerges to take its place.


So, what is malware, and what are the examples? Named after the Trojan Horse that Odysseus built to sneak his army into Troy, Trojan malware masquerades as a harmless application or file to gain access to an individual’s system. Once installed, the malware runs in the background without detection and quietly steals data or allows attackers to control a device remotely.

Computer viruses and worms are the most common types of Trojan malware. These attacks often enter a device through an email attachment or free-to-download program. Once inside the device, they spread to other computers and networks by copying themselves or injecting code into critical files that run the operating system or important programs.

Trojans can also evade antivirus software and other detection tools by employing time delays, polymorphic code, or device fingerprinting to stay hidden from security systems. This enables them to remain dormant on a device until triggered by a specific action or a certain amount of time passes, then act to execute their malicious activities.

Trojans can also be used to build a botnet by installing backdoors allowing an attacker to download additional malware to a device and control it remotely. Hackers can use these devices to launch distributed denial-of-service attacks and other cyberattacks. Unexplained procedures, processes, or programs in the background indicate a Trojan infection on your desktop or laptop computer. Trojans can also infect mobile devices like tablets and smartphones and redirect their traffic to a server controlled by an attacker.


Ransomware is one of the more dangerous types of malware, and it is growing alarmingly. It encrypts files and holds them hostage, until the victim pays a fee for decryption.

Attackers use a variety of methods to infect computers with ransomware. Some common ways include phishing attacks with malicious attachments and drive-by downloading (when a user unknowingly visits an infected website, malware is downloaded without the user’s knowledge). Other methods include exploiting vulnerabilities on Web servers or other software. Social engineering is another tactic attackers use to gain computer access: spoofing email addresses, for example.

Once infected, most victims don’t realize their computers have been attacked until they see a message telling them they’ve been hit and demanding payment to regain access to their data. Unfortunately, even if you pay the ransom, it’s unlikely that the attacker will provide the decryption key to unlock your files.

Some steps that you can take to protect yourself against ransomware and other threats include making regular backups. Also, keep operating systems and programs updated. Finally, a robust endpoint security solution can help prevent ransomware by monitoring file storage for suspicious behavior and blocking users and devices that exhibit the most dangerous types of behavior in real-time.


A term that sounds like something straight out of a spy movie, spyware infiltrates computers and mobile devices to gather information covertly. Hackers then use the info to steal from victims or target them for extortion. Some types of spyware include keyloggers, which record all the keystrokes a victim makes to reveal passwords, and rootkits, which hide on infected machines to exploit security vulnerabilities.

Most malware uses a variety of tactics to infect PCs, Macs, and mobile devices. Malware infections often spread through phishing emails, text messages, and ads that seem legitimate (social engineering) or by taking advantage of hardware or software vulnerabilities. Attackers can also deliver a combination of malware strains via a single attack package called a blended threat.

Some kinds of spyware are designed to track the activities of a user and are mainly used for marketing purposes (for example, companies can track where users visit on the Internet so they can serve them with targeted advertisements). Other kinds of spyware infiltrate systems through security vulnerabilities: worms are malicious programs that spread by exploiting multiple vulnerabilities; ransomware encrypts files and devices and demands payment in exchange for the keys; and Trojans (named after the Greek military strategy of using a Trojan horse to invade Troy) masquerade as other software or hardware, and trick users into unknowingly downloading and installing it.