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Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
Network Security Featuring
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Network Security Featuring

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  • 1. NETWORK SECURITY FEATURING VIRUS AND ANTIVIRUS Presented by Msc(IS) V.S.Lakshmi Women’s Degree & P.G. College K. Aparna
  • 2. NETWORK SECURITY-FEATURING VIRUS AND ANTIVIRUS
    • In early days, the information is kept in racks in the form of files and racks protected by locking. After inventing Data processing system (Computer systems) all the information is stored in the memory in the form of files. So, information security requirement increased. Automated tools are used to protect the data in the computer system. This type of security is the computer security.
    • After introducing distributed systems and Networks, the information is transmitted to others through communication facilities. Then Network security came into existence.
  • 3.
    • In this way information security is broadly divided into two categories:
    • Computer security
    • Network security
    • There is no clear boundaries between these two forms of security .
    • For example, one form of the publicized types of attack on the information system is the computer virus.
    • A virus may be introduced into a system physically through diskette and subsequently loaded.
    • Viruses may also arrive over internet.
    • In both the cases virus is resident on a computer system and internal tools are needed to detect and
  • 4.
    • recover from virus . These tools are called ‘ Antivirus ’
    • programs.These protect the system being effected by
    • the virus or protect after infection.
    • Fred Cohen, formally defines the term ‘Computer Virus’. The term V I R U S means VITAL INFORMATION RESOURSES UNDER SEIZED.
    • The term Vital Information means the important files of the computer.
    • A resource refers to the data or the content of the important files.
    • Under Seized means this files will be corrupted and they will be executed in the different manner.
    • The total meaning of the term VIRUS means the content of the important files will be rewritten or the garbage matter will be added to the file and they will be executed in a different fashion.
  • 5.
    • It can damage the operating system’s ability to control basic functions, and when applications programs are run, it can override activities also.
    • Two gentlemen in Pakistan, Basset Faro and Amada Alive created first ever virus BRAIN . Their program installed a copy of itself on every 360KB disk that was accessed and replaces the boot program which initiates the operating system.
    • Suriv-02 is the .exe Virus. IBM faced and outbreak of Cascade Virus and warned its users about Viruses.
    • In 1950’s and 1960’s scientists at Bell Laboratories created Viruses that battled each other trying to destroy opposing viruses without being caught.
  • 6.
    • In 1980’s Viruses escaped from computer science laboratories into the hands of unscrupulous programmers. The first ‘fast infector’ and ‘Stealth’ Viruses appeared.
    • The European Institute of Computer Antivirus Research (EICAR) was also founded in this year.
    • Virus programs can be written for virtually any platform including Windows 95/98/NT, NetWare, Macintosh, OS/2 and even Unix .
    • A recent study also evaluated the major effects of the infections such as loss of productivity, loss of critical data.
    • Much of the spread of viruses over networks and within organizations would be prevented if there were less exchange of executable code. Viruses may run
  • 7.
    • concurrently with the operating system or application programs they have infected, carrying out their tasks either openly or hidden in the background. These virus programs can be classified as following:
    • Virus: It is also a type of computer program. It will get itself attached to any on the program. These programs for which the virus was attached is called host program. It cannot exist without the presence of any other program.
    • Worm: These programs don't require host programs. These work individually unlike as virus programs. These can also generate more copies themselves.
    • Torjon Horse: It is a stand-alone program like as worm, and it can work independently. These Viruses cannot prepare more copies themselves.
  • 8.
    • Dropper :When a virus program is encrypted to any program then that will be called a Dropper. No virus scanner will identify these types of virus programs. When these Droppers are executed it will be copied to the other programs. These Droppers are very useful for the virus growth.
    • Joke Program : These programs give us the illusion that there was some virus program. In reality it doesn’t pose any problem. These programs also cannot prepare their own copies.
    • Viruses are classified according to their working and the harm done by them. The classification is as follows:
    • Boot viruses :These types of Virus destroy the Boot records of Hard disk and Floppy disk. When we try to boot the system these Virus will be loaded onto the memory. Example : Michylangelo, Farm, Disk killer, and Stone Virus.
  • 9.
    • Program virus :These are also file Viruses. This will harm the files containing .bin, .com, .exe, .ovl, .drv, and .sys as their extension. When these programs are executed these will load into the memory and will be copied to other files also.
    • Example : Sunday cascade.
    • Multi Pirate viruses :This type of Virus creates harm to the program files. When they are executed they will be stored onto the memory and extends its limits to the boot records. After this whenever we boot the system the Virus will be copied to memory and transferred to the remaining files also.
    • Steallth virus :These types of viruses are generally classified as the clever virus. These viruses will not be caught for any type of virus scanners. When we try to read this program the control or the execution
  • 10.
    • will be shifted to another memory location. It increases the size of the corrupted file by 9216 bytes and shows it normal by reducing the size when shown in directory.
    • Example: Frodo, Joshi, Whale etc.
    • Polymorphic viruses :These types of virus write different types of code for Virus files. The code of one Program varies with others, so it will be difficult to find them.
    • Example : Simulate, Evil, Phoenix, Proud, Virus101, Cascade etc.
    • Macro viruses :These are the new types of viruses which was created frequently. These were resulted after the creation of Macro for Documents and spreadsheets .
    • Example: DMV, Nuclear, Word concept.
  • 11.
      • According to a recent study conducted by the NCSA(N ational C omputer S ecurity A gency ), macro viruses were responsible for the largest number of infections (49 percent ). The most common source of macro virus infection was found to be e-mail attachments.
      • Symptoms of a Virus:
      • If a system was infected with a virus it will have some changes in the computer. The symptoms of a Virus are:
      • Decreasing the speed of the system.
      • Size of the file increases rapidly.
      • Some files will be automatically deleted by ignoring the user.
  • 12.
    • System will be halted or hanged when the program is under execution.
    • Systems memory will be reduced
    • Icons shape will change and so on.
    • Precautions to be taken:
    • When your floppies are used on other computers, they should be used only after "write protected”.
    • Don't keep the floppy disk when it is booting with a hard disk.
    • Have the backup for each and every important file.
    • Make a copy of all your system files in a good separate floppy.
    • Don't use the floppies, which are used elsewhere if it is required first check, the floppy with an Antiviral scanner.
  • 13.
    • Scan the complete disk with antiviral software.
    • Use physical safeguards to protect your system from outsiders.
    • Restrict access to your system physically and technically.
    • Scan e-mail attachments before reading them.
    • The ultimate protection is your backups.
    • Using a Antiviral software:
    • Though we have taken many precautions the system will be affected by Virus. Even if the virus on your system is very malicious, chances are that it will be activated only on a specific date or a similar trigger. At that we will require a Virus scanner to scan and to destroy the Virus. Due to the ever-evolving forms of attack, we can never be sure about our security.
  • 14.
    • At present there are many types of Antiviral software available in the market. They are F-Secure antivirus 3.0, Norton antivirus 4.0, PC-Cillin 97-3.0, Quick heal express etc. Full featured protection that includes scanning and activity trapping components. In addition such a package includes access control capability,which limits the ability of virus to penetrate a system. In this way we can try to protect the system. But viruses will be increasingly to spread propaganda and misinformation. So, extensive protection will be required.

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