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Computer Viruses

What is a computer virus?

What are the types of computer viruses?

What are the main virus characteristics?

Are there any wrong impressions about viruses?

What can I do to prevent my computer from being infected with viruses?

 What is a computer virus?

  •  A program written to intentionally enter a computer without the userís permission or knowledge
  •  After gaining access, the virus may attempt to execute certain tasks, called its payload Though some viruses do little but replicate, others can cause serious damage or effect program and system performance
  •  A virus should never be assumed harmless

What are the types of computer viruses?

In terms of what they infect:

  • Program : executable program files such as .com, .exe, .ovl, .drv, .sys, .bin, .vbx and .dll
  • Boot : Boot Record, Master Boot, FAT and Partition Table
  • Multipartite : Both program and boot infector

In terms of How they infect :

  •  Parasitic
  •  Trojan
  •  Worms

What are the main virus characteristics?

  •  Memory Resident
  •  Non-Resident
  •  Stealth (Full, Size)
  •  Encrypting( Polymorphic)
  •  Triggered Event
  •  In the Wild

Are there any wrong impressions about viruses?

  • Viruses canít spread using data files
  •  You canít get a virus by reading e-mail
  • Viruses canít damage your computer hardware
  • Boot sector viruses are the biggest threat
  •  Viruses donít work well in Windows

What measures to take to protect against viruses?

  1. Disable booting form drive (A:)
  2. Keep scan definitions up to date
  3. Institute Organization-wide policy:
  • Malicious code / browser scanning
  • Code Authentication
  • Disable Java & ActiveX controls
  1. Never run untrusted code
  2. Keep OS security patches up to date
  3. Educate yourself and your end-users
  4. Scan all files (default setting on Anti-Virus software is set to scan program files only)
  5. Scan e-mail attachment
  6. Keep browser version and security patches up to date
  7. Take a look at your browserís security settings and set them strong
  8. Consider: Scan at internet gateway/firewall (content scanning)
  9. Consider: Manage userís internet browser "Plug-inís"
  10. Subscribe to a security web site
   

 

 

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