Operating System and Virus (Introduction).pptx

Introduction

1. Short Quiz What is an Operating System? What is meant by GUI? How do computer viruses infection occur. (Give at least 2) What year the ILOVEYOU VIRUS was developed? What virus infected more than 10 million machines worldwide that lacked the appropriate patch (software bug controller). Give atleast 3 types of computer viruses? How to prevent computer viruses?

2. Short Quiz Answer An Operating System (OS) is an interface between the computer user and computer hardware. An operating system is a software that performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers. A user interface that displays graphics in addition to text when it communicates with the user. It utilizes windows, icons, menus, and pointers. It can arrive on a flash drives. They most easily spread by attachments in e-mail messages. Computer viruses also spread by using downloads on the Internet. 2000 created by Onel de Guzman from Ph Blaster worm, 2003 Boot sector virus, direct action virus, resident virus Exercise caution when downloading files from the Internet. Ensure that the source is a legitimate and reputable one.

3. Operating System and Viruses

4. Operating System (OS) It is an interface between computer user and computer hardware. It is software which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives, printers and etc.

5. Operating System (OS) It is the most important program that runs on a computer. It is considered as the “brain” of the computer system. It is used to run other programs such as MS Office and all other programs installed in the computer system. Without the OS the computer system is practically useless. Is a collection of programs that controls how the CPU, memory, and I/O devices work together.

6. Operating System (OS) The OS is the manager of all the computer system’s hardware and software. In layman’s term, the OS is a computer program that provides an interface for the user to communicate with the computer.

7. Important Functions of (OS) 1. Memory Management - refers to the management of Primary Memory or Main Memory. Main memory is a large array of words or bytes where each word or byte has its own address. An Operating System does the following activities for memory management. Keeps track of primary memory, i.e., what parts of it are in use by whom, and what parts are not in use. In multiprogramming, the OS decides which process will get memory when and how much. Allocates the memory when a process requests it to do so. De-allocates the memory when a process no longer needs it or has been terminated.

8. Important Functions of (OS) 2. Processor Management – in a multiprogramming environment, the OS decides which process gets the processor when and for how much time. This function is called process scheduling. An Operating System does the following activities for processor management. Keeps track of processor and status of the process. The program responsible for this task is known as a traffic controller. Allocates the processor (CPU) to a process. De-allocates processor when a process is no longer required.

9. Important Functions of (OS) 3. Device Management – an Operating System manages device communication via their respective drivers. It does the following activities for device management Keeps track of all devices. The program responsible for this task is known as the I/O controller. Decides which process gets the device when and for how much time. Allocates the device in an efficient way. De-allocates devices.

10. Important Functions of (OS) 4. File Management – A file system is normally organized into directories for easy navigation and usage. These directories may contain files and other directions. An Operating System does the following activities for file management. Keeps track of information, location, uses, status etc. The collective facilities are often known as file system. Decides who gets the resources. Allocates the resources. De-allocates the resources.

11. Important Functions of (OS) 5. Security – By means of passwords and similar other techniques, it prevents unauthorized access to programs and data. 6. Control Over System Performance – Recording delays between a request for a service and response from the system. 7. Job Accounting – Keeping track of time and resources used by various jobs and users.

12. Important Functions of (OS) 8. Error Detecting Aids – Production of dumps, traces, error messages, and other debugging and error- detecting aids. 9. Coordination Between Other Software And Users – Coordination and assignment of compilers, interpreters, assemblers, and other software to the various users of the computer systems.

13. Primary Purpose of an (OS) Maximize the productivity of a computer system by operating in the most efficient manner and minimizing the amount of human intervention. Most modern OSes utilizes a user interface to make interacting with the computer easy. The goal of user interface is to be “ user-friendly ”, which means that the software can be used easily by individuals with limited training.

14. Graphical User Interface (GUI) A user interface that displays graphics in addition to text when it communicates with the user. It utilizes windows, icons, menus, and pointers.

15. Is a malicious program that self-replicates by copying itself to another program. In other words, the computer virus spreads by itself into other executable code or documents. 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. In the process, a virus has the potential to cause unexpected or damaging effects, such as harming the system software by corrupting or destroying data. Computer Virus

16. It can arrive on a flash drives They most easily spread by attachments in e-mail messages. Computer viruses also spread by using downloads on the Internet. How do computer Viruses infection occur?

17. A computer virus attack can produce a variety of symptoms. Here are some of them: Frequent pop-up windows. Pop-ups might encourage you to visit unusual sites. Or they might prod you to download antivirus or other software programs. Changes to your homepage. Your usual homepage may change to another website, for instance. Plus, you may be unable to reset it. What are the signs of a computer virus?

18. Mass emails being sent from your email account. A criminal may take control of your account or send emails in your name from another infected computer. Frequent crashes. A virus can inflict major damage on your hard drive. This may cause your device to freeze or crash. It may also prevent your device from coming back on. Unusually slow computer performance. A sudden change of processing speed could signal that your computer has a virus. What are the signs of a computer virus?

19. Unknown programs that start up when you turn on your computer. You may become aware of the unfamiliar program when you start your computer. Or you might notice it by checking your computer’s list of active applications. Unusual activities like password changes. This could prevent you from logging into your computer. Disks or disk drives are inaccessible. Your flash drive won’t open and there’s an error message occur “Disk drive is inaccessible”. What are the signs of a computer virus?

20. The computer runs slower than usual. The computer stops responding, or it locks up frequently. The computer restarts on its own every few minutes and does not run as usual. Computer applications do not work correctly. Disks or disk drives are inaccessible. There’s a double extension on attachment that’s recently opened (e.g. .jpg , .gif , or .exe ). What are the signs of a computer virus?

21. Antivirus program cannot be installed or won’t run on the computer. Antivirus program cannot be restarted or is disabled for no reason. New icons appear on the desktop that are not placed there or not even associated with any recently installed programs. What are the signs of a computer virus?

22. How can you help protect your devices against computer viruses? Here are some of the things you can do to help keep your computer safe. Use a trusted antivirus product, such as Norton AntiVirus Basic, or Windows Defender, and keep it updated with the latest virus definitions. Avoid clicking on any pop-up advertisements. Always scan your email attachments before opening them. Always scan the files that you download using file-sharing programs. How to help protect against computer viruses?

23. Best practices for detecting and preventing viruses. 1. Do not open any files attached to an email from an unknown, or untrustworthy source or even if it appears to come from someone you know if the subject line is questionable. If the need to do so is there, always save the file to your hard drive before doing so. 2. Delete chain emails and junk email. Do not forward or reply to any to them. These types of email are considered spam, which is unsolicited, intrusive mail that clogs up the network. Computer Virus Prevention

24. Best practices for detecting and preventing viruses. 3. Exercise caution when downloading files from the Internet. Ensure that the source is a legitimate and reputable one. 4. When in doubt, always err on the side of caution. Do not open, download, or execute any files or email attachments. Not executing is the most important of these. Computer Virus Prevention

25. Boot Sector Virus – This type of virus infects the master boot record and it is challenging and a complex task to remove this virus and often requires the system to be formatted. Mostly it spreads through removable media. Direct Action Virus – This is also called non-resident virus, it gets installed or stays hidden in the computer memory. It stays attached to the specific type of files that it infect. It does not affect the user experience and system’s performance. Types of Computer Viruses

26. Resident Virus – Unlike direct action viruses, resident viruses get installed on the computer. It is difficult to identify the virus and it is even difficult to remove a resident virus. The resident viruses are troublesome due to the reason they can run unnoticed by antivirus and antimalware software by hiding in the system’s RAM. Multipartite Virus – This type of virus spreads through multiple ways. It infects both the boot sector and executable files at the same time. Spacefiller Virus – This is also called “Cavity Viruses”. This is called so as they fill up the empty spaces between the codes and hence does not cause any damage to the file. Types of Computer Viruses

27. Polymorphic Virus – These types of viruses are difficult to identify with a traditional anti-virus program. This is because the polymorphic virus alters its signature pattern whenever it replicates. Since virus removal programs depend on identifying signatures of malware, these viruses are carefully designed to escape detection and identification. When security software detects a polymorphic virus, the virus modifies itself thereby; it is no longer detectable using the previous signature. Types of Computer Viruses

28. Overwrite Virus – This type of virus deletes all the files that it infects. The only possible mechanism to remove is to delete the infected files and the end-user has to lose all the contents in it. Identifying the overwrite virus is difficult as it spreads through emails. Types of Computer Viruses

29. File Infectors – Few file infector viruses come attached with program files, such as .com or .exe files. Some file infector viruses infect any program for which execution is requested, including .sys, . ovl , . prg , and . mnu files. Consequently, when the particular program is loaded, the virus is also loaded. Besides these, the other file infector viruses come as a completely included program or script sent in email attachments. Types of Computer Viruses

30. Macro Viruses – As the name suggests, macro viruses particularly target macro language commands in applications like Microsoft Word. The same is implied on other programs too. In MS Word, the macros are keystrokes that are embedded in the documents or saved sequences for commands. The macro viruses are designed to add their malicious code to the genuine macro sequences in a Word file. However, as the years went by, Microsoft Word witnessed disabling of macros by default in more recent versions. Thus, cybercriminals started to use social engineering schemes to target users. In the process, they trick the user and enable macros to launch the virus. Types of Computer Viruses

31. Rootkit Viruses – a malware type which secretly installs an illegal rootkit on an infected system. This opens the door for attackers and gives them full control of the system. The attacker will be able to fundamentally modify or disable functions and programs. Like other sophisticated viruses, the rootkit virus is also created to bypass antivirus software. The latest versions of major antivirus and antimalware programs include rootkit scanning. Types of Computer Viruses

32. System or Boot-record Infectors – The Boot-record Infectors infect executable code found in specific system areas on a disk. As the name implies, they attach to the USB thumb drives and DOS boot sector on diskettes or the Master Boot Record on hard disks. Boot viruses are no more common these days as the latest devices rely less on physical storage media. Types of Computer Viruses

33. Late 1940s , John von Neumann proposed that it was theoretically possible for a computer program to replicate. 1950s , the theory was tested at Bell Laboratories through the development of Core Wars , where players created tiny computer programs that attacked, erased, and tried to propagate on an opponent's system. Origin of Computer Viruses

34. 1971, the Creeper program, often regarded as the first virus, was created by Bob Thomas of BBN. Creeper was actually designed as a security test to see if a self-replicating program was possible. It was—sort of. With each new hard drive infected, Creeper would try to remove itself from the previous host. Creeper had no malicious intent and only displayed a simple message: " I'M THE CREEPER. CATCH ME IF YOU CAN!" Origin of Computer Viruses

35. 1982, 15-year-old Rich Skrenta developed Elk Cloner , the first computer virus—not named that yet—that spread outside a laboratory. Skrenta created it as a joke for his friends, whose Apple II computers became infected by inserting a diskette with a game that hid the virus. 1983 , American Electrical Engineer Fred Cohen , coined the term virus to describe a self-replicating computer program. 1985 , the first Trojan horses appeared, posing as a graphics-enhancing program called EGABTR and as a game called NUKE-LA. Origin of Computer Viruses

36. 1986 , the Brain virus appeared and spread worldwide by 1987. Created by the two Pakistani brothers, Basit and Amjad Farooq Alvi . 1988 , two new viruses appeared: the Stone virus, and Internet worm. 1989 , the Dark Avenger, the first fast infector virus. Was a pseudonym of a computer virus writer from Sofia, Bulgaria . 1990 , first Polymorphic virus called 1260 or V2PX . Created by Mark Washburn. 1995 , the WinWord Concept virus. Origin of Computer Viruses

37. 1999 , the Melissa macro virus, which costs corporations millions of dollars due to computer downtime and lost productivity. Created by David L. Smith . 2000 , the VBS_LOVELETTER virus, a.k.a. the Love Bug and the ILOVEYOU virus in which losses were estimated at $10 billion, with a 1:5 ratio of infection. Created by Onel de Guzman from Philippines. 2003 , the Blaster worm infected more than 10 million machines worldwide that lacked the appropriate patch (software bug corrector). Origin of Computer Viruses

38. 2003 , the SoBig worm , considered as the fastest spreading virus, capable of sending massive amounts of junk e-mail or spam. January 2004 , the MyDoom virus set a new record, spreading even faster than SoBig , causing even more damage. Origin of Computer Viruses

39. Origin of Computer Viruses 2014 , One of the most recent of the major viruses came out, Heartbleed burst onto the scene and put servers across the Internet at risk. Heartbleed , unlike viruses or worms, stems from vulnerability in OpenSSL, a general purpose, open source cryptographic library used by companies worldwide. OpenSSL periodically sends out "heartbeats" to ensure that secure endpoints are still connected. Users can send OpenSSL a specific amount of data and then ask for the same amount back—for example, one byte. If users claim they're sending the maximum allowed, 64 kilobytes, but only send a single byte, the server will respond with the last 64 kilobytes of data stored in RAM, notes security technologist, Bruce Schneier , which could include anything from user names to passwords to secure encryption keys.

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