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 user’s 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 :
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 can’t spread using data files
- You can’t get a virus by reading e-mail
- Viruses can’t damage your computer hardware
- Boot sector viruses are the biggest threat
- Viruses don’t work well in Windows
What
measures to take to protect against viruses?
- Disable booting form drive (A:)
- Keep scan definitions up to date
- Institute Organization-wide policy:
- Malicious code / browser scanning
- Code Authentication
- Disable Java & ActiveX controls
- Never run untrusted code
- Keep OS security patches up to date
- Educate yourself and your end-users
- Scan all files (default setting on Anti-Virus
software is set to scan program files only)
- Scan e-mail attachment
- Keep browser version and security patches up to date
- Take a look at your browser’s security settings and set them
strong
- Consider: Scan at internet gateway/firewall (content scanning)
- Consider: Manage user’s internet browser "Plug-in’s"
- Subscribe to a security web site
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