How Computer Viruses Work




by Marshall Brain




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  • Introduction to
    How Computer Viruses Work
    
  • Virus
    Origins
    
  • Virus
    History
  • Virus
    Evolution
    
  • E-mail
    Viruses
    
  • Worms
    
  • See more »
    
    
    
    
    7. How to Protect
       Your Computer from Viruses
       
    8. Lots More
       Information
       
    9. See all Computer
       & Internet Security articles
    10. More Computer Videos »
    11. Computer
        Trojan Remover
        Detect & Remove
        over 500,000 traces of Spyware & Trojans. Recommended.
        www.pctools.com
        
    12. Computer
        Virus Spyware
        Free Spyware Scan.
        Award-Winning Anti-Spyware. Download Now.
        www.STOPzilla.com
        
    13. Mac-based
        SMB Security
        Don't rely on your
        default Mac IT security settings. Buy McAfee today
        McAfee.com/SmallBusiness
        
    14. Viruses - A virus is a small piece of software that
        piggybacks on real programs. For example, a virus might attach itself to a
        program such as a spreadsheet program. Each time the spreadsheet program runs,
        the virus runs, too, and it has the chance to reproduce (by attaching to other
        programs) or wreak havoc.
        
    15. E-mail viruses - An e-mail virus
        travels as an attachment to e-mail messages, and
        usually replicates itself by automatically mailing itself to dozens of people in
        the victim's e-mail address book. Some e-mail viruses don't even require a
        double-click -- they launch when you view the infected message in the preview
        pane of your e-mail software [source: Johnson].
        
        
    16. Trojan
        horses - A Trojan horse is simply a computer program. The
        program claims to do one thing (it may claim to be a game) but instead does
        damage when you run it (it may erase your hard disk). Trojan
        horses have no way to replicate automatically.
        
    17. Worms - A worm is a small piece
        of software that uses computer networks
        and security holes to replicate itself. A copy of the worm scans the network for
        another machine that has a specific security hole. It copies itself to the new
        machine using the security hole, and then starts replicating from there, as
        well.

  
  

  ­In this article, we will discuss viruses -- both "traditional" viruses
  and e-mail viruses -- so that you can learn how they work and understand how to
  protect yourself.

 
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The music industry does like to insist that filesharing - aka
illegal downloading - is killing the industry: that every one of the millions of
music files downloaded each day counts as a "lost" sale, which if only it could
somehow have been prevented would put stunning amounts of money into
impoverished artists' hands. And, of course, music industry bosses'
wallets.

What To Do If Your Personal Information Has Been Compromised




Companies or institutions that keep personal information about you have an
obligation to safeguard it. Still, from time to time, the personal information
they hold may be accidentally disclosed or deliberately stolen. If your
information falls into the wrong hands, it may be misused to commit fraud
against you.




If you get a notice that your personal information may have been compromised,
taking certain steps quickly can minimize the potential for the theft of your
identity.




If the stolen information includes your financial accounts, close compromised
credit card accounts immediately. Consult with your financial institution about
whether to close bank or brokerage accounts immediately or first change your
passwords and have the institution monitor for possible fraud. Place passwords
on any new accounts that you open. Avoid using your mother's maiden name, your
birth date, the last four digits of your Social Security number (SSN) or your
phone number, or a series of consecutive numbers.




If the stolen information includes your Social Security number, call the
toll-free fraud number of any one of the three nationwide consumer reporting
companies and place an initial fraud alert on your credit reports. This alert
can help stop someone from opening new credit accounts in your name.




Equifax: 1-800-525-6285; www.equifax.com; P.O. Box 740241, Atlanta, GA
30374-0241




Experian: 1-888-EXPERIAN (397-3742); www.experian.com; P.O. Box 2002, Allen, TX
75013




TransUnion: 1-800-680-7289; www.transunion.com; Fraud Victim Assistance
Division, P.O. Box 6790, Fullerton, CA 92834-6790




An initial fraud alert stays on your credit report for 90 days. When you
place this alert on your credit report with one nationwide consumer reporting
company, you'll get information about ordering one free credit report from each
of the companies. It's prudent to wait about a month after your information was
stolen before you order your report. That's because suspicious activity may not
show up right away. Once you get your reports, review them for suspicious
activity, like inquiries from companies you didn't contact, accounts you didn't
open, and debts on your accounts that you can't explain. Check that information
— like your SSN, address(es), name or initials, and employers — is correct.




If the stolen information includes your driver's license or other
government-issued identification, contact the agencies that issued the documents
and follow their procedures to cancel a document and get a replacement. Ask the
agency to "flag" your file to keep anyone else from getting a license or another
identification document in your name.




Once you've taken these precautions, watch for signs that your information is
being misused. For example, you may not get certain bills or other mail on time.
Follow up with creditors if your bills don't arrive on time. A missing bill
could mean an identity thief has taken over your account and changed your
billing address to cover his tracks. Other signs include:



• receiving credit cards that you didn't apply for;
  
• being denied credit, or being offered less favorable credit terms, like a
  high interest rate, for no apparent reason; and
  
• getting calls or letters from debt collectors or businesses about
  merchandise or services you didn't buy.



Continue to read your financial account statements promptly and carefully,
and to monitor your credit reports every few months in the first year of the
theft, and once a year thereafter. For more information on getting your credit
reports free once a year or buying additional reports, read Your Access to Free
Credit Reports at www.ftc.gov/bcp/edu/pubs/consumer/credit/cre34.shtm.




If your information has been misused, file a report about your identity theft
with the police, and file a complaint with the Federal Trade Commission at www.ftc.gov/idtheft. Read Take Charge:
Fighting Back Against Identity Theft for detailed information on other steps to
take in the wake of identity theft.




The FTC works for the consumer to prevent fraudulent, deceptive, and unfair
business practices in the marketplace and to provide information to help
consumers spot, stop, and avoid them. To file a complaint or to get free information on consumer
issues, visit ftc.gov or call toll-free,
1-877-FTC-HELP (1-877-382-4357); TTY: 1-866-653-4261. The FTC enters consumer
complaints into the Consumer Sentinel
Network, a secure online database and investigative tool used by hundreds of
civil and criminal law enforcement agencies in the U.S. and abroad. 

What it does ...
The
Hosts file
contains the mappings of IP addresses to host names. This file is loaded into
memory (cache) at startup, then Windows checks the Hosts file before it
queries any DNS servers, which enables it to override addresses in the DNS. This
prevents access to the listed sites by redirecting any connection attempts back
to the local (your) machine. Another feature of the HOSTS file is its ability to
block other applications from connecting to the Internet, providing the entry
exists.

You can use a HOSTS file to block ads, banners, 3rd
party Cookies, 3rd party page counters, web bugs, and even most hijackers. This is accomplished by blocking the
connection(s) that supplies these little gems.