Computer Virus History & Maintenance PDF

COMPUTER REVIEWER COMPUTER VIRUS HISTORY The first theory of self replicating computer programs was done in 1949 by John von Neumann gave lectures at the University of Illinois about the "Theory and Organization of Complicated Automata" later published as the ("Theory of self-reproducing automata")...

COMPUTER REVIEWER COMPUTER VIRUS HISTORY The first theory of self replicating computer programs was done in 1949 by John von Neumann gave lectures at the University of Illinois about the "Theory and Organization of Complicated Automata" later published as the ("Theory of self-reproducing automata") He is also known as “The theoretical Father of Computer Virology.” The Creeper Virus self-replicating program written by Robert Thomas at BBN Technologies in 1971 gained access via the ARPANET and copied itself to the remote system where the message, "I'm the creeper, catch me if you can!" was displayed. The Reaper program was created to delete Creeper. In 1982 a program called "Elk Cloner" was the first personal computer virus to appear outside the single computer or computer lab where it was created. Written in 1981 by Richard Skrenta, a ninth grader at Mount Lebanon High School near Pittsburgh, it infected Apple II operating systems through floppy disks. Displays a short poem beginning "Elk Cloner: The program with a personality." It was Fred Cohen, who coined (invent/devised) the term “computer virus”.In 1984 Fred Cohen from the University of Southern California wrote his paper "Computer Viruses – Theory and Experiments". It was the first paper to explicitly call a self-reproducing program a "virus", a term introduced by Cohen's mentor Leonard Adleman. Other MAJOR viruses Jerusalem: A DOS virus that lurked on computers, launched on any Friday the 13th, and deleted applications. Melissa: A mass-mailing macro virus that brought the underground virus scene to the mainstream in 1999. It earned its creator 20 months in prison. (MMAV) ILOVEYOU Virus (email message): ILOVEYOU, sometimes referred to as Love Bug or Love Letter for you, was a computer worm that infected over ten million Windows personal computers on and after 5 May 2000. - The ILOVEYOU virus was created in the Philippines by Onel de Guzman, a computer science student at AMA Computer College in Manila (Extra info) Lesson 2. MAINTAINING YOUR COMPUTER SYSTEMS 5 Reason Why Computer Maintenance is Important 1. Early Detection of Issues. Computers can be temperamental, and we all know that small issues can become huge problems before we know it. Having regular maintenance checks done on your computer can eradicate small issues before they become big problems. 2. Prevention against Viruses and Malware. There are innumerable viruses and malware already out there just waiting to infect computers, and more are being created every day. Keeping computers well-maintained can keep both viruses and malware away and keep your computer running in tip-top shape. 3. Speed up Your Computer. Over time our computers get clogged up with files and everything gets disorganized and fragmented affecting our productivity. Regular maintenance can keep your computer running at an optimal speed. 4. Maximize your Software Efficiency. Another reason your computer may slow down over time is that your software package is getting old. Having regularly scheduled maintenance on your computer will clean out any issues and have your software running perfectly again. 5. Prevent Data Loss. When your computer starts running slowly or begins having occasional lag/freeze, it can require a system reboot that can ultimately result in lost data. However, keeping your computer maintained will lessen the likelihood of these instances and keep your data safe and secure. 3 STEPS IN MAINTAINING COMPUTER SYSTEMS 1. KNOW YOUR A, B AND C’s (Antimalware/Antivirus, Backup and Clean up) 2. CLEAN YOUR HARDWARE 3. KNOW WHAT TO FIX STEP 1 KNOW YOUR A, B AND C’s (Antimalware/Antivirus, Backup and Clean up) “A” – ANTIMALWARE and ANTIVIRUS Malware - Malware is a catch-all term for any type of malicious software, regardless of how it works, its intent, or how it’s distributed. Malware is software written specifically to harm and infect the host system Malware categories include the following: Worms. Is a standalone program that can self-replicate and spread over a network. It works to eat up all the system operating files and data files on a drive. A graduate student created the first worm (the Morris worm) in 1988 as an intellectual exercise.  Ransomware. Demands that users pay a ransom—usually in bitcoin or other cryptocurrency—to regain access to their computer. The infamous Cryptolocker is one type of ransomware. Scareware. Attempts to frighten the victim into buying unnecessary software or providing their financial data. Scareware pops up on a user's desktop with flashing images or loud alarms, announcing that the computer has been infected. Adware and spyware. Adware also known as advertising-supported software that pushes unwanted advertisements at users. Adware is programmed to examine which Internet sites the user visits frequently and to present and feature related advertisements. Not all adware has malicious intent. Spyware secretly collects information about the user. It may record the websites the user visits, information about the user's computer system and vulnerabilities for a future attack, or the user’s keystrokes. Spyware that records keystrokes is called a keylogger. This spyware’s presence is typically hidden from the host and it is very difficult to detect. Trojan. A type of virus that is designed to make a user think they are a safe program and run them. They may be programmed to steal personal and financial information, and later take over the resources of the host computer’s system files. Virus. is a malicious program that self-replicates by copying itself to another program. The purpose of creating a computer virus is to infect vulnerable systems, gain admin control and steal user sensitive data. Hackers design computer viruses with malicious intent and prey on online users by tricking them. How does a computer virus operate? A computer virus operates in two ways. The first type, as soon as it lands on a new computer, begins to replicate. The second type, the infected program needs to run to be executed. How did the virus spread? Before computer networks became widespread, most viruses spread on removable media, particularly floppy disks. Today, viruses spread via the internet. A virus may send a web address link as an instant message to all the contacts (e.g., friends and colleagues' e-mail addresses) stored on an infected machine. What is ANTIMALWARE? An anti-malware is a software that protects the computer from malware such as spyware, adware, and worms. It scans the system for all types of malicious software that manage to reach the computer. An anti-malware program is one of the best tools to keep the computer and personal information protected. Anti-malware does its job using behavior monitoring, sandboxing and malware removal. What is an ANTIVIRUS? Antivirus software scans a file, program, or an application and compares a specific set of code with information stored in its database. If it finds code that is identical or similar to a piece of known malware in the database, that code is considered malware and is quarantined or removed. Signs of Malware/Virus Infection Slower system performance Frequent crashes Files multiplying/duplicating on their own New files or programs in the computer / Programs running on their own Files, folders or programs getting deleted or corrupted Have programs that do not open, run slow or close unexpectedly. Mass emails being sent from your email account Show popups both online and/or offline Changes to your homepage or passwords Present problems when trying to recognize external hardware. Show a blue screen with the error code. How to Avoid this Types of Computer Malwares/Viruses 1. Avoid clicking on suspicious links. 2. Never open files with a double file extension, e.g. filename.txt.vbs. 3. Scan email attachments before opening it. 4. Avoid clicking on pop-up advertisements and get a pop-up blocker for your web browser. 5. When routed to another website, don’t do anything, and immediately leave the site. 6. Install a reliable antivirus program and always keep it up to date. “B” - BACKUP One may reduce the damage done by viruses by making regular backups of data (and the operating systems) on different media, that are either kept unconnected to the system (most of the time, as in a hard drive), read-only or not accessible for other reasons, such as using different file systems. This way, if data is lost through a virus, one can start again using the backup (which will hopefully be recent). Where to BACKUP? External Hard drive. Allows you to save your files or your computer software with a good storage capacity. If you own a Mac, you can use their built-in Time Machine application to back up your computers' content to an external hard drive. Time Machine routinely (hourly and daily) backs up all your files to an external hard drive Flash Drive. Small USB drives are almost as inexpensive as discs, even as their capacity increases. They have the advantage of being ultra-portable. But locking one multi-GB flash drive in a safe deposit box is easier than storing discs or hard drives. Cloud. The cloud refers to online storage. Sometimes it's used by a service, like Google Drive, to store your data. - Google Drive - Mega - iCloud - OneDrive - Dropbox “C” - CLEAN-UP Having an effective computer filing system can make a huge difference in your everyday life. First, it helps to save time, but most importantly, it helps you to be more organized. Using the “File Explorer” Shortcut keys to open: Windows (⊞) + E Libraries where in most files fall in: Documents, Downloads, Music, Pictures, and Videos. Then the drives, this is a list of your hard drives where all your files are stored. For example: The C: Which is also known as the C-drive, usually refers to the hard disk drive (HDD). Other letters are also used to indicate storage media, for example, which refers to a removable disk (USB). Storage media, such as DVDs, USBs and hard drives, do not save data to the disks on the computer. Files are stored on a computer inside folders. Folders are used to organize a computer’s files so that it can be found easier. A folder will contain subfolders and then files. File Path A file path shows the location of where a file, web page, or other item is located on the computer. Deleting Files The Delete command enables you to remove files from the storage device. This command can be used to either remove files that you do not need anymore, or to make more space on the storage device. STEP 2 CLEAN YOUR HARDWARE CLEAN YOUR HARDWARE In cleaning or maintaining your computer case. You may use a damp cloth without the use of solvents. Gently clean your monitors with a dry lint-free cloth when cleaning with tougher stains – use a LCD screen cleaner. Be cautious in using solvents because this may cause skin irritations. Use a damp lint-free cloth in cleaning the surfaces of your keyboard / mouse. Do not spray water directly. For harder to reach parts, you may use a compressed air canister. Do not eat or drink over your computer. Organize your cords. Computers must be covered when not in use. Check if fans are working Don’t block air vents, and will not obstruct airflow. STEP 3 KNOW WHAT TO FIX Simple Solutions to Common Problems Most of the time, problems can be fixed by using simple troubleshooting techniques, such as closing and re-opening the program. It's important to try these simple solutions before resorting to more extreme measures. If the problem still isn't fixed, you can then try other troubleshooting techniques, such as reinstalling the software. Always check the cables: Many computer problems are related to an issue in the cables and connections. The easiest first step you can take to troubleshoot most problems is to check all related cables and connections. Isolate the problem: If possible, try to isolate the problem. Take notes about error messages: If your computer gives you error messages, be sure to write down as much information as possible. If the basic troubleshooting steps don't work, you may need the information. Remember the steps you've taken, or write them down: Once you start troubleshooting, you will want to remember what you have done, so you don't repeat yourself. If you can't remember it, then write it down. Lesson 3: Categories of Computer Handout 1. Purpose General Purpose Computer – A General Purpose Computer can perform any kind of job with equal efficiency simply by changing the application program stored in main memory. General computers can do various everyday tasks such as writing a word processing letter, Document preparation, recording, financial analysis, printing documents, creating databases, and calculations with accuracy and consistency. The size, storage capacity, and cost of such computers are mainly less. The ability of these computers is limited in performing specialized tasks. Still, it has versatility and is useful for serving people’s basic needs at home or at the workplace in the environment. Special Purpose Computer - A Special Purpose Computer is the one that is designed to perform only one particular or special task. The size, storage capacity, and cost of such computers mainly depend on the nature and size of the work. The special computer needs specific processors and input and devices to conduct work efficiently. The program or instructions set is permanently stored in such a machine. It does its single task very quickly and it cannot be used for any other purpose. Examples of special purpose computers are computers that are used for special purposes in weather forecasting, space research, agriculture, engineering, meteorology, satellite operation, traffic control, and research in chemical sciences. 2. Data Handling Analog Computer - In analog computers, the data is accepted with an instrument to be directly measured, and therefore no numbers need to be converted into codes. An analog computer performs tasks using continuous data (the physical amount that changes continuously). Analog computers are used primarily to measure physical units like the voltage, pressure, electric current, temperature, then convert to digits, the efficiency of this computer increases when we get the result of the data (output) in graphs. Analog Computers cannot store statistics. They are used in the fields of technology, science, research, engineering, education, etc. Examples: An analog computer installed on a petrol pump measures the amount of petrol coming out of the pump and appears in liters. And calculates its value. These quantities vary continuously while measuring the amount, such as the temperature of a human body changes consistently. The Speedometer of a car measures the speed, changes in temperature in the body with a thermometer’s help, and weighs our body with a weighing machine. Digital Computer - Digital computers use discrete electrical signals for operation rather than continuous electrical signals as analog computers have, making the most common form of computers today because of their versatility, speed, and power. A digital computer operates directly on a decimal digit that represents either discrete data or symbols. They run on electronic signs, and the binary numeral method Binary System 0 or 1 is used for calculation. Their speed is fast. It can perform arithmetic operations such as addition, occurrence, subtraction, multiplication, or division and all types of logical(mathematical) operations. Today, most of the computers available in the market are digital computers. Examples of Digital Computers: Accounting machines Calculators IBM PC Personal Desktop Computers Laptops, Smartphones, and Tablets Digital clock, etc Hybrid Computer – Hybrid computers utilize the best qualities of both analog and digital computers and united by a single control system. They are suited for situations where digital processing of data collected in analog form is desirable. Hybrid computers are not only too expensive, units are extremely fast when driving equations, even when those calculations are incredibly complex. For example – in a hospital intensive care unit (ICU), analog devices may measure a patient’s heart function, temperature etc. these measurements may then be converted into numbers and supplied to digital devices. 3. Function Server - Server usually refers to a computer that is dedicated to providing one or more services. A server is expected to be reliable (e.g. error-correction of RAM; redundant cooling; self-monitoring, RAID), fit for running for several years, and giving useful diagnosis in case of an error. For even increased security, the server may be mirrored. Many smaller servers are actually personal computers that have been dedicated to provide services for other computers. Example of Server: Database server File server Web server Terminal server Workstation - Workstations are computers that are intended to serve one user and may contain special hardware enhancements not found on a personal computer. The term is used to describe desktop PCs with more CPU power, high memory and processing powers. These are more expensive and are mostly used in designing, animation and other complex mathematical calculations. Embedded Computers - is a microcontroller or microprocessor based system devised for specific function. Embedded Computers perform specific functionality and are used today in various applications. Embedded Computer may be a part of a large system but it relies on its own processor. Cell phones, cameras, automotive systems etc. are some of the common examples of embedded computers. 4. Size Microcomputer – Also called a Personal Computer. A microcomputer can be defined as a small, relatively inexpensive computer designed for an individual user whose CPU is a microprocessor. These computers consist of many parts like Input and Output devices, Software, operating systems, networks, and Servers all these need to connect to form complete Personal Digital Computer. Only one person can work on a single PC at a time, but its operating system is multitasking. The PC can be connected to the Internet to enhance user experience. This can be installed in any work area or even at home for personal use. Types of Microcomputers: Desktop computers – A case put under or on a desk. The display may be optional, depending on use. The case size may vary, depending on the required expansion slots. Very small computers of this kind may be integrated into the monitor. Laptop Computers and notebook computers – Portable and all in one case. Palmtop Computer, Digital Diary, PDAs. Minicomputer – also called as midrange servers, which is in between micro and mainframe computers. Minicomputer is a digital and multi-user computer system with the connection of more than one CPU. Thus, many people can work on these computers simultaneously instead of a single person. Also, it can be processed with other accessories like a printer, plotter, etc. The minicomputers are used as real-time applications in Industries, bookings, and Research Centres. Banks also use minicomputers for preparing payroll for employees’ salaries, records, tracking of financial accounts, etc. As well as in the field of Higher Education and Engineering. Mainframe computer - Mainframe computer performs multiple instructions in parallel to multiple users. They are very big in size and are expensive. A large number of peripherals can be attached to them. They are generally used in large networks of computers with the mainframe being the model point of the network. The storage capacity of the mainframe is enormous, these computers have several microprocessors that have the ability to function the data at too high performance and speed. Mainframe is a highly efficient computer capable of simultaneously solving complex calculations and continuously for a long time. Applications: Uses of Mainframe Computer – Mainframe computers are mainly used by departmental and commercial organizations like Banks, Companies, Scientific research centers, and governmental departments like railways. These computers can work for 24 hours. Supercomputer - Supercomputers are the most expensive computer, they are large and have multiple CPUs that can handle many instructions in parallel. They are used in complex calculations such as weather forecasting, fluid dynamics, nuclear simulations, theoretical astrophysics, and complex scientific computations. Supercomputers are focused on a few critical tasks. Supercomputer processing speeds are measured in floating point operations per second, or FLOPS.