Antivirus

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Antivirus

  1. 1. Welcome
  2. 2. Topic
  3. 3. Overview • What is anti virus? & short history of it. • How an antivirus work? • Configuring antivirus software? • Some of the symptoms of an infected computer? • Deleting Identified Virus files manually? • Antivirus Effectiveness. • Antivirus Damaged files. • Online Antivirus scanning. • some popular Antivirus.
  4. 4. What is anti virus?Antivirus Software is a computer program thatidentify and remove computer viruses, and othermalicious software like Worms and Trojans from aninfected computer. Not only this, an antivirussoftware also protects the computer from furthervirus attacks.The first anti-virus software in 1987. Fix, a Germanastrophysicist and amateur computer programmerdeveloped software to combat the first computervirus “in the wild," which means that the virus hadescaped the confines of the lab or network .
  5. 5. How an Antivirus works ?An Antivirus works Using dictionary ApproachThe antivirus software examines each andevery file in a computer and examines itscontent with the virus definitions stored in itsvirus dictionary. A virus dictionary is an inbuiltfile belonging to an antivirus software thatcontains code identified as a virus by theantivirus authors.
  6. 6. Configuring an antivirus software ?Configuring your Antivirus software Adjust thesettings to scan all files. Also, ensure that realtime scanning is enabled by default. Create arecovery/reference/cure disk because if a bootsector or MBR virus attack the system, it may failto boot. In that case, recovery cure disk can beused to boot the system and remove the virus.Read the vendors manual. This will help you tounderstand the advanced options and how to usethem according to your preference.
  7. 7. Some of the symptoms of infected computerFolder Options disappears from the Tools. Now,hidden files cannot be viewed. Changing registryvalues has no effect. Reedit doesn’t works, whenyou try to invoke it from the RUN box. TaskManager has been disabled by Administrator. InMy Computer, Auto play option appears insteadof Open in every drive you enter i.e. when youclick on your drive letters (C, D, E etc) a windowopens to select any one program to Open with.Computer becomes slow and there is noticeabledelay in characters to appear on screen when youpress in keyboard.
  8. 8. Deleting Identified Virus files manuallyDeleting Identified Virus files manually Identify files say likeautorun.inf or mswin32.dll.vbs in the root of all drives or inyour system drive. You can also delete a file from DOS. thecommand DIR /w/a displays all hidden files and folders. withcommand attrib -s -h -r <filename>. Then del <filename> A virus also hides itself in the SystemVolume Information and PREFETCH folder. So it might be agood idea to turn off System Restore for a while. To preventfuture infections in your USB Drive, what you could try iscreate an empty autorun.inf file and set read only attribute toit. This should prevent a malicious autorun.inf taking its place .
  9. 9. Antivirus Effectiveness Studies in December 2007 showed that theeffectiveness of antivirus software had decreased inthe previous year, particularly against unknown or zeroday attacks. The computer magazine ct found thatdetection rates for these threats had dropped from 40-50% in 2006 to 20-30% in 2007. At that time, the only exception was the NOD32antivirus, which managed a detection rate of 68percent Anti-virus programs are not always effectiveagainst new viruses, even those that use non-signature-based methods that should detect newviruses. The reason for this is that the virus designerstest their new viruses on the major anti-virusapplications to make sure that they are not detectedbefore releasing them into the wild.
  10. 10. Antivirus Damaged filesFiles which have been damaged by computerviruses are normally damaged beyondrecovery. Anti-virus software removes thevirus code from the file duringdisinfection, but this does not always restorethe file to its undamaged state. In suchcircumstances, damaged files can only berestored from existing backups; installedsoftware that is damaged requires re-installation.
  11. 11. Some popular Antivirus:
  12. 12. When select an Antivirus Software ?An Antivirus Software Real-Time Scanningantivirus software is automatically running in thebackground on a continuous basis, scanning filesand folders for possible virus attacks as they areopened or executed, and checking e-mails as theyare downloaded. Most commercial antivirussoftware provide real time scanning.
  13. 13. Online Antivirus scanning Some antivirus vendors maintain websites with free online scanning capability of the entire computer, critical areas only, local disks, folders or files. Periodic online scanning is a good idea for those that run antivirus applications on their computers because those applications are frequently slow to catch threats..
  14. 14. Online Antivirus scanning cont….• One of the first things that malicious software does in an attack is disable any existing antivirus software and sometimes the only way to know of an attack is by turning to an online resource that isnt already installed on the infected computer
  15. 15. Thanks For Joining

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