Computer Viruses

MalwareMalicious softwarePrograms designed to infiltrate or damage a computer system without the owner's informed consent.

Viruses, worms, Trojan horses, adware, spyware

Virus

• A virus is a program that reproduces its own code by attaching itself to other executable files

• The virus code is executed when the infected file is executed.

• Most viruses do their "job" by placing self-replicating code in other programs

The Life Cycle

• Viruses embed themselves into the code of software

• They are harmless until the infected program is actually started (executed)

Who Writes Viruses- and Why?

• Viruses can be written by anyone • It could include researchers for demonstration

purposes • In some cases, they can be written by

pranksters. • These viruses get passed around and can be

altered by other people.

Are All Computer Viruses Harmful?

• Every computer virus ever written takes up disk space

• Many of them are able to remain in the computer's memory taking control

• Some viruses are written to halt the computer • There are viruses created to deliberately

destroy data on the disk

What do they do?

• slower processing• decreased memory • a disk drive LED lighting up for no apparent

reason • a screen going blank when you touch a certain

letter on your keyboard • delete data• copy password

How do you get the virus??

• Viruses are contracted by downloading files from the Internet

• Close to 75% of all viruses are contracted through friendly means

How do you prevent virus??

Use less popular e-mail clients; virus developers don't target these e-mail clients.

Mac users are less prone to contracting computer viruses (remember virus creators are looking for the highest body count)

Anti-virus software is not a ‘cure all’ Run a virus scan on any executable (.exe) files or

MS Word/Excel Files that are emailed to you

Common Types

• Boot Sector - Stays resident by infecting the boot sector of the computer

• FAT Virus - infects the File Allocation Table of a hard drive, these usually cause a loss of files that are on a hard drive

• Memory viruses - execute and stay resident in memory

Macro viruses - viruses that attach themselves to documents in the form of macros. Usually in Microsoft Word and Microsoft Excel documents

• CMOS viruses - viruses that make themselves resident in the CMOS . These viruses can damage the hardware of the computer

• Worms - A computer worm is a software program that is designed to copy itself from one computer to another, without human interaction.

• Unlike a computer virus, a worm can copy itself automatically.

• You might have heard of specific computer worms, including the Sasser worm, the Blaster worm, and the Conficker worm.

Trojan Horse - designed to cause damage or do something malicious to a system, but are disguised as something useful.

Unlike viruses, these don't make copies of themselves.

Trojan horses are designed to allow a hacker remote access to a target computer system.

Spyware

• Software that performs certain behaviors, generally without appropriately obtaining your consent first, such as: – Advertising – Collecting personal information – Changing the configuration of your computer

Spam

• Unsolicited e-mail• annoying and time consuming • people have lost money to bogus offers

Phishing• “We suspect an unauthorized transaction on your

account. To ensure that your account is not compromised, please click the link below and confirm your identity.”

• “During our regular verification of accounts, we couldn’t verify your information. Please click here to update and verify your information.”

• “We are updating all email accounts on our mail server. Please click the link below and update your username and password. If you don’t reply within 48 hours your account will be closed”

Hackers

• a hacker is a person who breaks into computers, usually by gaining access to administrative controls

• most hackers are thieves, looking for personal data or bank/ credit card information

How do hackers gain access to your account?

• worms, viruses and Trojan horse programs make your computer vulnerable to remotely controlled exploits

• Use ’security holes’ through which they can gain entry without much trouble

• use programs that are designed to figure out the passwords to your accounts

• use Brute Force password attacks

The Bottom Line• To prevent your computer from contracting a

virus, use a virus protection program. • Keep up-dated on what viruses are going

around. • Don't open email that is suspicious or that you

don't recognize the senders name. • Activate firewall• Always back up your files! • If your computer does contract a virus, be

prepared to reformat and start all over again!

Hopefully, you will not be the victim of a virus or hacker!