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Virus presentation


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  • 1. 02/28/12
  • 2.
    • A kind of software programs
      • produced by unknown people and harmful to the computers
    • Some varieties of these software are the
      • Viruses , Worms and Trojan horses
  • 3.
    • The term “Virus" is often used in common
      • to describe all kinds of malware (malicious software) including   adware  and spyware  programs that do not have the reproductive ability.
  • 4.
    • Trojan horse perform a desirable function for the user in addition to the expected function
    • Leaks information
    • Usually does not reproduce
  • 5.
    • A worm is a self replicating malware computer program, which uses a computer network to send copies of itself to other computers and it may do so without any user intervention. It does not need to attach itself to an existing program.
  • 6.
    • Sometimes display unwanted messages
    • Some tend to destroy programs or data
    • Clog computer memory and hence sometimes result
    • in system crashes
    • Format hard disks, Damage programs, Delete files
    02/28/12 Viruses
  • 7.
    • Simply replicate themselves
    • Presents text, video, or audio messages making the user know their presence
    • Bug-ridden, and these bugs may lead to system crashes and data loss
  • 8.
    • A viruses can copy itself and infect a computer
      • without permission or knowledge of the user
    • attaches itself to other software programs or data files
  • 9.
    • Spreads from computer to computer when the host is taken to the uninfected computer
      • over a network such as over the Internet or carrying it on a removable medium - a floppy disk, CD, or USB drive
  • 10.
    • Many viruses are existed in the Internet today and new ones are discovered every day.
      • spread via downloaded software and data files, and email attachments etc.
  • 11.
    • Some old viruses are installed themselves into the disk boot sector
      • runs when the user boot the computer from the disk
  • 12.
    • Some viruses spread through instant messaging
      • A virus, in an infected machine, may send a web address link as a message to other contacting machines
      • Thinking the link is from a friend (a trusted source), the recipient may sometimes follow the link to the website.
  • 13.
    • C/C++
    • Pascal
    • VBA
    • Unix Shell Scripts
    • Javascript
  • 14.
    • Unlike biological viruses, computer viruses do not simply evolve by themselves
      • deliberately created by programmers, or by people who use virus creation software
  • 15.
    • Viruses are written as
      • research projects, pranks, vandalism,
      • to attack the products of specific companies,
      • to distribute political messages,
      • and financial gain from identity theft,
      • spyware, and cryptoviral extortion.
  • 16.
    • Some virus writers
      • consider their creations to be works of art
      • See virus writing as a creative hobby
    02/28/12 Releasing computer viruses is a crime in most jurisdictions
  • 17.
      • File infector virus
      • Infect program files
      • Boot sector virus
      • Infect the system area of a disk
      • Master boot record virus
      • infect disks in the same manner as boot sector viruses. The difference between these two virus types is where the viral code is located.
  • 18.
      • Multi-partite virus
      • Infect both boot records and program files.
      • Macro virus
      • Infect data files. Example: Microsoft Office Word, Excel,
      • PowerPoint and Access files
  • 19.
    • Melissa virus spread in Microsoft Word documents sent via e-mail.
    • How it works ?
    • Created the virus as word document
    • Uploaded to an internet newsgroup
    • Anyone who download the document and opened it would trigger the virus.
    • Send friendly email messages to first 50 people in person’s address book
  • 20.
    • Melissa Virus was the fastest spreading virus ever seen.
    • Forced a number of large companies to shut down their e-mail systems.
  • 21.
    • Contained a piece of code as an attachment.
    • Double Click on the attachment triggered the code.
    • Sent copies of itself to everyone in the victim’s address book
    • Started corrupting files on the victim’s machine.
  • 22.
    • Code Red made huge headlines in 2001
    • It slowed down internet traffic when it began to replicate itself.
    • Each copy of the virus scanned the internet for Windows NT or Windows 2000 that don’t have security patch installed.
    • Each time it found an unsecured server, the virus copied itself to that server.
  • 23.
    • Designed to do three things
    • Replicate itself for the first 20 days of each month
    • Replace web pages on infected servers with a page that declares “Hacked by Chinese”
    • Launch a concreted attack on the White House Web server.
  • 24.
    • The Morto virus emerged in the summer of 2011.
    • It attempts to propagate itself to additional computers via the Remote Desktop Protocol
    • (RDP).
    • Morto spreads by forcing infected systems to scan for servers allowing RDP login.
    •   Once Morto finds an RDP-accessible system, it attempts to log in to a domain or local system account named 'Administrator' using a number of common passwords.
  • 25.
    • To avoid detection by users, viruses
    • employ different deception methods
      • They do not make themselves to
        • change the date of last modified
        • increase file sizes
        • damage the files
  • 26.
      • They kill the tasks associated with antivirus
      • software before it can detect them.
  • 27.
    • Take regular backups (including OS) on different media, unconnected to the system (most of the time)
    02/28/12 How to prevent damages caused by viruses?
  • 28.
    • Use backups on optical media like CD and DVD (read-only), as they can no longer be affected by viruses.
    • Use an OS on a bootable, to start the computer if the installed OS become unusable.
    02/28/12 How to prevent damages caused by viruses?
  • 29.
    • Install reliable anti-virus software
      • the most important step you can take towards keeping your computer clean of viruses
    • Update your anti-virus software regularly
      • variations of viruses and new ones can be slipped if your software is not current
  • 30.
    • Get immediate protection
      • Configure your anti-virus software to boot automatically on start-up and run at all times
  • 31.
    • Don't automatically open attachments
      • ensure that you examine and scan email and other attachments before they run as they might contain viruses
    • Scan all incoming email attachments
      • Do not open any email attached files if the subject line is questionable, unexpected or the source (address) is unknown, suspicious or untrustworthy
  • 32.
    • Delete chain emails and junk email
      • Do not forward or reply to any of them, they clogs up the network
      • Some viruses can replicate themselves and spread through email as a chain
  • 33.
    • Be careful when downloading files from the Internet
      • Ensure that the source is a legitimate and reputable one
      • save all downloads to one folder and test them with your own anti-virus software before use
  • 34.
    • Backup your files on a regular basis
    • Always scan new files for viruses before you use them
  • 35.
    • If your computer is on a network, make sure you have security steps in place to prevent unauthorized users putting files on your computer
  • 36.
    • Take care using USB flash cards, CDs, zip
    • and floppy disks
      • The more computers flash cards, CDs, zip cards
      • and floppies have been used on, the better the chance
      • of a virus infecting them – clean them before use
  • 37. 02/28/12