Computer Science 2210/0478 (Notes)
Chapter: 5
Topic: Malware
Malware, short for malicious software, is any software specifically designed to cause harm, steal data, or
disrupt the normal functioning of computer systems, networks, or devices. There are several types of
malware, each with its unique characteristics and methods of operation:
1. Virus: A computer virus is a type of malware that attaches itself to legitimate files or programs and
replicates itself once the infected file is executed. Viruses can cause various forms of damage, such as
corrupting or deleting files, consuming system resources, or causing system crashes. They typically
spread through sharing infected files or emails, downloading malicious attachments, or visiting
compromised websites.
2. Worm: A worm is a self-replicating malware that does not require user intervention to spread. Unlike
viruses, worms do not need to attach themselves to existing files or programs. Instead, they exploit
vulnerabilities in computer networks or operating systems to replicate and distribute themselves. Worms
can cause damage by consuming bandwidth, deleting files, or installing backdoors for unauthorized
access.
3. Trojan Horse: A Trojan horse is a type of malware that tricks as a legitimate program or file, tricking
users into downloading and installing it. Once installed, Trojans can perform various malicious activities,
such as stealing sensitive data, deleting files, or providing remote access to attackers. Trojans do not
replicate themselves like viruses or worms.
4. Spyware: Spyware is a type of malware designed to secretly monitor and collect information about
users' activities without their knowledge or consent. This can include keystrokes, browsing history,
passwords, or other sensitive data. Spyware is often distributed through deceptive downloads or bundled
with other software, and it can be used for identity theft, targeted advertising, or corporate espionage.
5. Adware: Adware, short for advertising-supported software, is a type of malware that displays unwanted
advertisements on a user's device, often in the form of pop-up ads or banners. While not always
malicious, adware can negatively impact the user experience by slowing down the system, consuming
bandwidth, or redirecting users to malicious websites. Some adware can also collect data about users'
browsing habits to display targeted ads or sell the information to third parties.
6. Ransomware: Ransomware is a type of malware that encrypts a user's files or locks their computer,
rendering it unusable until a ransom is paid to the attacker in exchange for a decryption key or unlock
code. Ransomware typically spreads through phishing emails, malicious attachments, or compromised
websites. In recent years, ransomware attacks have become increasingly sophisticated, targeting not only
individual users but also businesses and organizations, causing significant financial losses and
operational disruptions.
Page 1 of 2
Computer Science 2210/0478 (Notes)
Chapter: 5
Topic: Malware
In summary, malware encompasses various types of malicious software designed to harm, disrupt, or
steal data from computer systems, networks, or devices. Common types of malware include viruses,
worms, Trojan horses, spyware, adware, and ransomware, each with distinct characteristics and methods
of operation. Protecting against malware involves using antivirus software, keeping software and systems
up to date, and following safe browsing and downloading practices.
Page 2 of 2
