Types of Threats
Computer systems are vulnerable to many threats ranging from errors, harming stored data, information or corrupting programs installed on the computers. The following are some common types of threats to the computers:
Computer virus is the most common and well known computer security threat. A computer virus is a program written intentionally to alter the way a computer operates, without the permission or knowledge of the user.
A virus replicates and executes itself by attaching the copies to other files such as program files or documents. When activated a virus may:
- Damage or delete files
- Erase data in hard disk
- Cause erratic system behavior
- Display annoying messages, etc.
Computer worms are malicious programs that replicate and spread independently and harm the computer. Worms spread through network and over the Internet to computers that are connected to the Internet.
Worms can also spread by copying themselves from disk to disk or by e-mail. SQL Slammer, The Blaster Worm, Sasser worms, Melissa and ILOVEYOU are examples of computer worms.
Computer Worms can:
- Destroy files in the system
- Slow down the computer
- Cause some programs to stop working
Adware is software which automatically plays, displays, or downloads advertisements to a computer usually without user’s knowledge. These advertisements can be in the form of a pop-up. They record user’s behavior on the Internet, display ads and can even download other malicious software on to the computer.
Hacking can be defined as the unauthorized use of computer, network and its resources. People who indulge themselves in computer hacking activities are called Hackers. Hackers are computer experts who use their expertise for malicious purposes.
- Client or customer information
- Credit card details and social security numbers, for identity fraud or theft
- E-mail addresses, which may be used for spamming.
Indicators of Security Threats
- The computer runs slower than usual.
- The computer locks up or stops responding.
- The computer suddenly restarts on its own.
- Frequently used programs become suddenly slow to load and operate.
- Applications and disk drives are suddenly inaccessible.
- Unusual error messages appear.
- Unexpected icons appear on the desktop.
- Antivirus software is disabled or does not run.
Ways through which Virus, Worms and Adware Spread
There are different ways through which a Virus, Worms and Adware spread from one computer to the other computer.
A Virus, Worms and Adware can spread through:
- Infected Flash Drives or Disks
- E-mail attachments
- Surfing insecure websites
- Installing Pirated Software
1. Infected Flash Drives or Disks
Flash drives and disks are convenient, popular and easy to use storage devices. Flash drives and disks are the main source of spreading viruses among computers. Once an infected flash drive or a disk is connected to a healthy computer, it becomes infected with viruses. In this way virus spread from one computer to the other.
2. E-mail Attachments
E-mail attachment is a file that can be sent with an e-mail from one computer to the other. An e-mail virus ¡s a computer code sent as an e-mail attachment. If activated, it may cause some harmful effect, such as destroying certain files on the hard disk and causing the attachment to be forwarded to everyone in the address book. E-mail viruses distribute themselves automatically by e-mail.
These viruses require the user on double-clicking on the attachment containing viruses. This causes the malicious code to mail itself to other people from that computer.
3. Surfing Insecure Websites
A Website that is set up to spread a virus or for some other unethical purpose ¡s an insecure website. These websites engage in questionable or unethical practices and attempt to:
- Automatically access the computer when users visit them.
- Install Adware that may cause a flurry of pop ups to appear on the screen.
4. Installing Pirated Software
Software which has been duplicated and distributed without authorization is called Pirated software. Pirated software may be faulty or loaded with malware and may contain viruses.
Pirated software can threaten the safety of computer users. These software products may be used to steal personal information, load computer with viruses, or engage in activities which can harm the computer.