COMPUTER VIRUS

 

COMPUTER VIRUS

INTRODUCTION

In the modern digital era, where computers, smartphones, and the internet have become an inseparable part of human life, the issue of cybersecurity threats has gained increasing importance. Among the most common and damaging forms of such threats is the computer virus. A computer virus can be defined as a type of malicious software program that, much like a biological virus, has the ability to replicate itself and spread from one host to another, often without the knowledge or consent of the user. These programs are designed with harmful intent and can cause a wide range of problems—from slowing down system performance and corrupting files to stealing sensitive personal data and even rendering entire systems inoperable.

The term computer virus was first introduced in the early 1980s, when researchers noticed the possibility of self-replicating code that could infect and disrupt computer systems. Since then, viruses have evolved in complexity, capability, and impact, paralleling the rapid advancement of information technology. Today, viruses are not just isolated to personal computers but also pose risks to mobile devices, servers, and entire networks, making them a global concern. With increasing reliance on online transactions, cloud computing, and interconnected systems, the destructive potential of a computer virus has grown significantly, affecting individuals, businesses, and even national security infrastructures.

One of the unique characteristics of a computer virus is its ability to disguise itself within seemingly harmless files, emails, or programs. Once executed, the virus becomes active and can carry out its malicious purpose, whether that involves deleting data, hijacking system resources, or opening a gateway for hackers to infiltrate systems. Unlike other malware, a computer virus generally requires user action to spread—such as downloading an infected file, clicking on a malicious link, or inserting an infected USB device—making user awareness a critical factor in prevention.

The consequences of computer viruses are far-reaching. On a personal level, individuals may lose valuable files, face identity theft, or experience financial loss. On a larger scale, businesses can suffer from operational shutdowns, data breaches, and reputational damage. History has recorded several infamous virus outbreaks, such as the “ILOVEYOU” virus in 2000 and the “Mydoom” virus in 2004, which caused billions of dollars in damages worldwide. These incidents highlight the destructive power of viruses and the urgent need for strong protective measures. 

In light of these risks, cybersecurity practices such as installing updated antivirus software, practicing safe browsing habits, and regularly updating operating systems have become essential. Additionally, the development of more advanced detection technologies, artificial intelligence-driven security tools, and global cooperation in combating cyber threats reflects the seriousness with which the world views the danger of computer viruses.

Thus, a computer virus is not merely a technical nuisance but a significant threat to the safety, privacy, and functionality of digital environments. Studying computer viruses is therefore crucial, not only to understand their nature and mechanisms but also to develop effective strategies to safeguard information systems in an age where technology governs almost every aspect of human activity.

    In the ever-expanding digital world, where information technology has become central to human life, the threats posed by malicious software are increasing day by day. Collectively, these harmful programs are referred to as malware, a term derived from “malicious software.” Malware is any program or file that is intentionally designed to cause damage to a computer, server, client, or network. Its primary goal may range from simply disrupting normal operations to stealing sensitive information, monitoring user activity, or even providing unauthorized access to hackers. Among the many types of malwares, spyware and Trojan horses are some of the most widespread and dangerous forms.

1. MALWARE

Malware is an umbrella term that includes various types of harmful software such as viruses, worms, ransomware, spyware, adware, trojans, and rootkits. Unlike ordinary software, malware is created with malicious intent. It may spread through infected files, email attachments, compromised websites, USB devices, or network vulnerabilities. Once inside a system, malware can:

•     Corrupt or delete files.
•      Slow down or crash the operating system.
•     Steal confidential data like passwords, bank details, and personal information.
•     Monitor online activity and browsing habits.
•     Allow cybercriminals remote access to a system.

Malware is designed to harm and exploit your computer or network. It can steal sensitive information like passwords and credit card numbers, disrupt your system’s operations, and even allow attackers to gain unauthorized access to your device. Some types of malwares, such as ransomware, encrypt your files and demand payment to unlock them, while spyware monitors your activities and sends the information back to the attacker. Additionally, malware can spread to other devices on the same network, making it a significant threat. Protecting your devices with up-to-date antivirus software and being cautious about your open links and attachments can help mitigate these risks.

The impact of malware can be devastating not only for individuals but also for organizations, as it may lead to data breaches, financial losses, and reputational damage. Cybercriminals often use malware as a weapon for cyberattacks, making cybersecurity awareness and defense strategies essential.

                                                           TYPES OF MALWARES

2. SPYWARE

Spyware is a specific type of malware designed to spy on the user’s activities without their knowledge. It secretly installs itself on a computer or mobile device and operates in the background, collecting information such as browsing history, search habits, keystrokes, login credentials, and even credit card details. Spyware often enters a system through free software downloads, malicious websites, or infected email attachments. It can also be bundled with seemingly legitimate programs, tricking users into installing it. Once active, spyware can:

•     Track keystrokes (keyloggers) to steal usernames and passwords.
•      Monitor internet browsing for targeted advertising.
•      Capture screenshots or record system activity.
•     Send collected information to third-party attackers.
•      Keylogging, which is recording everything the user types, including login credentials and banking information
•      Recording audio and video
•      Remote control of the entire device

Spyware is especially dangerous because it compromises privacy. Victims may not notice its presence, but meanwhile, sensitive data like online banking details or private messages may already be stolen.

 3. TROJAN HORSE (TROJAN)

A Trojan horse, often called simply a Trojan, is a type of malware that disguises itself as legitimate software to deceive users. The name originates from the ancient Greek story of the Trojan Horse, where soldiers hid inside a wooden horse to secretly enter the city of Troy. Similarly, a Trojan hides inside seemingly harmless files or applications, but once executed, it opens the door for attackers.

Unlike viruses and worms, Trojans do not replicate themselves. Instead, they rely on tricking users into downloading and running them. After activation, a Trojan can:

•     Install backdoors, giving hackers remote control of the system.
•     Download additional malware.
•     Modify, steal, or delete files.
•     Record user activity or disable security software.
•    Turn a device into part of a botnet for large-scale attacks.

Trojans are one of the most common methods used by cybercriminals because they rely on social engineering—fooling people into trusting what looks like a safe file, email, or program.

Malware, spyware, and Trojans are among the most critical threats in the field of cybersecurity. While malware serves as a broad category of harmful programs, spyware focuses on secretly gathering personal information, and Trojans act as deceptive tools that give attackers access to systems. Their combined impact can lead to loss of data, identity theft, financial damage, and compromised privacy. In today’s interconnected world, understanding these threats is essential. Preventive measures such as using updated antivirus software, avoiding suspicious downloads, regularly updating operating systems, and practicing safe browsing habits can help reduce the risk of infection. 

PREVENTIVE MEASURES

FIREWALL AND ANTIVIRUS SOFTWARE

In today’s digital age, where cyber threats such as malware, spyware, trojans, ransomware, and phishing attacks are continuously increasing, preventive measures play a crucial role in ensuring the safety of computer systems and networks. Among the most effective and widely used preventive tools are firewalls and antivirus software. These tools act as the first line of defense, protecting devices, data, and networks from unauthorized access, harmful programs, and cybercriminal activities.

FIREWALL

A firewall is a security system designed to monitor and control incoming and outgoing network traffic based on predetermined security rules. Its primary function is to act as a barrier between a trusted internal network (such as a personal computer or corporate network) and untrusted external networks (such as the internet). By filtering data packets, the firewall determines whether they should be allowed or blocked, thereby preventing suspicious or harmful traffic from entering the system.

Types of Firewalls:

·       Packet-filtering firewall – Inspects packets of data against rules (e.g., IP address, port number) and blocks unauthorized ones. These operate at the network layer and provide basic filtering of IP packets. They check the headers of packets to determine their source and destination, then decide whether to allow or deny the packets based on predefined rules.

·       Stateful inspection firewall – Monitors the state of active connections and makes decisions based on traffic patterns. These not only examine the headers but also monitor the state of active connections. They make decisions based on the state of the connection and the rules set by the network administrator.

·       Proxy firewall – Acts as an intermediary between the user and the internet, providing anonymity and protection. These operate at the application layer and act as an intermediary between end users and the internet. They filter messages at the application layer and can perform more detailed inspections of traffic.

·       Next-generation firewall (NGFW) – Combines traditional firewall features with advanced tools such as intrusion prevention, deep packet inspection, and application awareness. These include features like deep packet inspection (DPI), intrusion detection systems (IDS), and intrusion prevention systems (IPS). They can filter packets based on their content and block more sophisticated attacks

Functions of a Firewall:

•      Blocks unauthorized access from hackers.
•      Prevents malicious programs or data from entering the system.
•       Filters out harmful websites and content.
•      Monitors network activity to detect unusual behavior.

A firewall is therefore essential for protecting both individual users and organizations, as it ensures that only safe, verified data is allowed to pass through the network.

ANTIVIRUS SOFTWARE

While a firewall primarily controls network traffic, antivirus software focuses on protecting the system itself by detecting, preventing, and removing malicious software. Antivirus programs are designed to scan files, applications, and memory for signs of harmful code such as viruses, worms, spyware, ransomware, or trojans. Once detected, the software either quarantines or deletes the malicious program to prevent further damage.

Key Features of Antivirus Software:

·       Real-time protection – Continuously monitors the system for threats.

·       Automatic updates – Regularly updates virus definitions to stay protected against new threats.

·       Scanning options – Allows users to run quick scans, full system scans, or custom scans.

·       Quarantine and removal – Isolates and deletes infected files safely.

·       Email and web protection – Blocks malicious attachments, phishing links, and unsafe downloads.

Popular Antivirus Programs: Norton, McAfee, Kaspersky, Bitdefender, Avast, and Windows Defender are some well-known antivirus solutions used globally.

While both firewalls and antivirus software are effective individually, their combined use provides stronger protection. A firewall filters incoming and outgoing traffic, blocking unauthorized access before it even reaches the computer. On the other hand, antivirus software acts as a defence inside the system, detecting and eliminating any malicious code that may bypass the firewall. Together, they create a multi-layered security system that greatly reduces the risk of infection, data theft, and cyberattacks.

Cyber threats are constantly evolving, and no system connected to the internet is completely safe. However, preventive measures such as firewalls and antivirus software significantly reduce the risks. A firewall protects the network by controlling access and blocking unauthorized connections, while antivirus software actively detects and removes harmful programs from within the system. When used together, they serve as powerful tools to safeguard personal data, financial information, and organizational resources in an increasingly vulnerable digital world. Thus, maintaining updated firewalls and antivirus programs is not just advisable but absolutely essential for anyone who values cybersecurity.

REFERENCE

1. Thomas, M. (2015). Computer Viruses. International Journal of Engineering Research & Technology (IJERT), 3(28). https://doi.org/10.17577/IJERTCONV3IS28019
2. https://www.geeksforgeeks.org/computer-science-fundamentals/what-is-antivirus-software/
3. Source: GeeksforGeeks https://share.google/i6BK4sDOVulcIt4IZ
4. https://www.fortinet.com/resources/cyberglossary/firewall
5. https://www.mcafee.com/blogs/privacy-identity-protection/understanding-trojan-viruses-and-how-to-get-rid-of-them/