TECHNOLOGY AND COMMUNICATION IN EDUCATION

UNIT IV : STUDENT SAFETY ON THE NET

CONTENTS

• Introduction
• Computer virus
• Malware
• Spyware
• Trojan
• Prevention measures
• Firewall
• Anti-virus software
• Conclusion

​

Introduction

Computer Virus

​

A computer virus is a type of malicious software, or malware, that spreads between computers and causes damage to data and software. Computer viruses aim to disrupt systems, cause major operational issues, and result in data loss and leakage. A key thing to know about computer viruses is that they are designed to spread across programs and systems. Computer viruses typically attach to an executable host file, which results in their viral codes executing when a file is opened. The code then spreads from the document or software it is attached to via networks, drives, file-sharing programs, or infected email attachments.

Common Signs of Computer Virus

• Speed of system

A computer system running slower than usual is one of the most common signs that the device has a virus. This includes the system itself running slowly, as well as applications and internet speed suffering. If a computer does not have powerful applications or programs installed and is running slowly, then it may be a sign it is infected with a virus.

• Pop-up messages

Unwanted pop-up windows appearing on a computer or in a web browser are a telltale sign of a computer virus. Unwanted pop-ups are a sign of malware, viruses, or spyware affecting a device.

• Programs self executing

If computer programs unexpectedly close by themselves, then it is highly likely that the software has been infected with some form of virus or malware. Another indicator of a virus is when applications fail to load when selected from the Start menu or their desktop icon.

​

​

• Accounts being logged out

Some viruses are designed to affect specific applications, which will either cause them to crash or force the user to automatically log out of the service.

• Crashing of the device

System crashes and the computer itself unexpectedly closing down are common indicators of a virus. Computer viruses cause computers to act in a variety of strange ways, which may include opening files by themselves, displaying unusual error messages, or clicking keys at random.

• Mass e-mails being sent from our account

Computer viruses are commonly spread via email. Hackers can use other people's email accounts to spread malware and carry out wider cyberattacks. Therefore, if an email account has sent emails in the outbox that a user did not send, then this could be a sign of a computer virus.

• Changes to the homescreen

Any unexpected changes to a computer—such as your system’s homepage being amended or any browser settings being updated—are signs that a computer virus may be present on the device.

​

​

​

Types of Computer Virus

• Resident Virus

Viruses propagate themselves by infecting applications on a host computer. A resident virus achieves this by infecting applications as they are opened by a user. A non-resident virus is capable of infecting executable files when programs are not running.

• Multipartite Virus

A multipartite virus uses multiple methods to infect and spread across computers. It will typically remain in the computer’s memory to infect the hard disk, then spread through and infect more drives by altering the content of applications. This results in performance lag and application memory running low. Multipartite viruses can be avoided by not opening attachments from untrusted sources and by installing trusted antivirus software. It can also be prevented by cleaning the boot sector and the computer’s entire disk.

• Direct Action

A direct action virus accesses a computer’s main memory and infects all programs, files, and folders located in the autoexec.bat path, before deleting itself. This virus typically alters the performance of a system but is capable of destroying all data on the computer’s hard disk and any USB device attached to it. Direct action viruses can be avoided through the use of antivirus scanners. They are easy to detect, as is restoring infected files.

​

​

​

• Browser Hijacker

A browser hijacker manually changes the settings of web browsers, such as replacing the homepage, editing the new tab page, and changing the default search engine. Technically, it is not a virus because it cannot infect files but can be hugely damaging to computer users, who often will not  be able to restore their homepage or search engine. It can also contain adware that causes unwanted pop-ups and advertisements.Browser hijackers typically attach to free software and malicious applications from unverified websites or app stores, so only use trusted software and reliable antivirus software.

• Overwrite Virus
• Overwrite viruses are extremely dangerous. They can delete data and replace it with their own file content or code. Once files get infected, they cannot be replaced, and the virus can affect Windows, DOS, Linux, and Apple systems. The only way this virus can be removed is by deleting all of the files it has infected, which could be devastating. The best way to protect against the overwrite virus is to use a trusted antivirus solution and keep it updated.�Web Scripting Virus

A web scripting virus attacks web browser security, enabling a hacker to inject web-pages with malicious code, or client-side scripting. This allows cyber criminals to attack major websites, such as social networking sites, email providers, and any site that enables user input or reviews. Attackers can use the virus to send spam, commit fraudulent activity, and damage server files.Protecting against web scripting is reliant on deploying real-time web browser protection software, using cookie security, disabling scripts, and using malicious software removal tools.

• File Infector
• A file infector is one of the most common computer viruses. It overwrites files when they are opened and can quickly spread across systems and networks. It largely affects files with .exe or .com extensions. The best way to avoid file infector viruses is to only download official software and deploy an antivirus solution.�Network Virus�Network viruses are extremely dangerous because they can completely cripple entire computer networks. They are often difficult to discover, as the virus could be hidden within any computer on an infected network. These viruses can easily replicate and spread by using the internet to transfer to devices connected to the network. Trusted, robust antivirus solutions and advanced firewalls are crucial to protecting against network viruses.�Boot Sector Virus�A boot sector virus targets a computer’s master boot record (MBR). The virus injects its code into a hard disk’s partition table, then moves into the main memory when a computer restarts. The presence of the virus is signified by boot-up problems, poor system performance, and the hard disk becoming unable to locate. Most modern computers come with boot sector safeguards that restrict the potential of this type of virus.

Malwares

• Malware (short for “malicious software”) is a file or code, typically delivered over a network, that infects, explores, steals or conducts virtually any behavior an attacker wants. And because malware comes in so many variants, there are numerous methods to infect computer systems. Though varied in type and capabilities, malware usually has one of the following objectives: �Provide remote control for an attacker to use an infected machine.�Send spam from the infected machine to unsuspecting targets.�Investigate the infected user’s local network.�Steal sensitive data.

Spyware

Spyware is a type of malicious software – or malware – that is installed on a computing device without the end user’s knowledge. It invades the device, steals sensitive information and internet usage data, and relays it to advertisers, data firms or external users.Any software can be classified as spyware if it is downloaded without the user’s authorization.

Spyware is controversial because, even when it is installed for relatively innocuous reasons, it can violate the end user’s privacy and has the potential to be abused.

Spyware is one of the most common threats to internet users. Once installed, it monitors internet activity, tracks login credentials and spies on sensitive information. The primary goal of spyware is usually to obtain credit card numbers, banking information and passwords.

Trojan

A Trojan horse, or Trojan, is a type of malicious code or software that looks legitimate but can take control of your computer. A Trojan is designed to damage, disrupt, steal, or in general inflict some other harmful action on your data or network.�A Trojan acts like a bona fide application or file to trick you. It seeks to deceive you into loading and executing the malware on your device. Once installed, a Trojan can perform the action it was designed for.�A Trojan is sometimes called a Trojan virus or a Trojan horse virus, but that’s a misnomer. Viruses can execute and replicate themselves. A Trojan cannot. A user has to execute Trojans. Even so, Trojan malware and Trojan virus are often used interchangeably.

Preventive Measures

• Computer viruses can easily spread through the Internet and email, causing potential harm to a computer’s data, files and hard drive. Viruses are commonly disguised as hyperlinks, pop-ups or email attachments of images, greeting cards or audio or video files. Use the following tips to help keep your computer safe from viruses, hackers and other malicious attacks.
• Don’t open email attachments or click on hyperlinks from unknown senders.�Use your spam blocking or filtering tools to block unsolicited emails, instant messages and pop-ups.�Use passwords that are hard to guess and change them regularly. Do not store user names and passwords on websites.�Exercise caution when downloading files from the Internet. Only download from trusted sources.

Firewall

• A Firewall is a network security device that monitors and filters incoming and outgoing network traffic based on an organization’s previously established security policies. At its most basic, a firewall is essentially the barrier that sits between a private internal network and the public Internet. A firewall’s main purpose is to allow non-threatening traffic in and to keep dangerous traffic out.
• Types of Firewalls�Packet filtering:A small amount of data is analyzed and distributed according to the filter’s standards.
• Proxy service:Network security system that protects while filtering messages at the application layer.�Stateful inspection:Dynamic packet filtering that monitors active connections to determine which network packets to allow through the Firewall.
• Next Generation Firewall (NGFW):Deep packet inspection Firewall with application-level inspection.

Antivirus Software

• Antivirus software (abbreviated to AV software), also known as anti-malware, is a computer program used to prevent, detect, and remove malware.
• Antivirus programs run continuously in the background protecting the computer each time it is at risk. Malicious codes are spread from contact with corrupted files. A good example is from an infected flash drive or hard disk and, more popularly, through files sent across the internet. By opening or downloading emails, downloading apps, engaging suspicious sites, etc., your computer can be infected with any of this malware.
• Some popular examples are: Avast, AVG Antivirus Business edition, Bitdefender Total security, Kaspersky, McAfee, Malwarebytes, Norton, SecureMac, Trend Micro Antivirus+Security, Webroot Security Anywhere etc.

Conclusion

Viruses are harmful and can destroy data, slow down system resources, and log keystrokes.Cybercriminals aren’t creating new viruses all the time, instead they focus their efforts on more sophisticated and lucrative threats. When people talk about “getting a virus” on their computer, they usually mean some form of malware—it could be a virus, computer worm, Trojan, ransomware or some other harmful thing. Viruses and malware continue to evolve, and often cybercriminals use the type that gives them the best return at that particular time. The year 2022 has been quite productive for online criminals, and even with the constant battle of the authorities, their number does not seem to have diminished. Worse still, attacks aimed at businesses have increased, and some of the new threats are extremely hard to avoid.Individuals and businesses alike need to invest in anti-malware solutions. Sadly, personal, financial, and corporate data have become a currency of sorts. As the latest virus threats can affect anyone, we should all remember that even the least important piece of information we possess is priceless.

Done by:

Arathi A S

S1 B.Ed (2022-2024)

Optional Subject – English

Sree Narayana Gurukripa B.Ed College, Pothencode