We've all heard about computer viruses. We've probably all had one at some point. But we're increasingly hearing about different malicious computer software, like worms, spyware, adware, hijackers, and Trojans, and these terms confuse a lot of people. This lesson will help clear up the confusion.
There are so many new threats to computer systems that we've created a general term to describe them all. That term is malware. Malware is a combination of the words malicious and software and is used to describe, in general terms, any type of bad code we may find on a computer. Any software that gets installed on your machine that performs some unwanted or harmful task, normally for the benefit of some third party, qualifies as malware.
Types of Malware
What is a worm?
A worm is computer code that spreads without user interaction. Most worms begin as email attachments that infect a computer when they're opened. The worm scans the infected computer for files, such as address books or temporary webpages, that contain email addresses. The worm uses the addresses to send infected email messages, and frequently mimics (or spoofs) the "From" addresses in later email messages so that those infected messages seem to be from someone you know. Worms then spread automatically through email messages, networks, or operating system vulnerabilities, frequently overwhelming those systems before the cause is known. Worms aren't always destructive to computers, but they usually cause computer and network performance and stability problems.
What is a trojan horse?
A trojan horse is a malicious software program that hides inside other programs. It enters a computer hidden inside a legitimate program, such as a screen saver. Then it puts code into the operating system that enables a hacker to access the infected computer. Trojan horses do not usually spread by themselves. They are spread by viruses, worms, or downloaded software.
What is spyware?
Spyware can install on your computer without your knowledge. These programs can change your computer’s configuration or collect advertising data and personal information. Spyware can track Internet search habits and can also redirect your web browser to a different website than you intend to go to.
What is rogue software?
A rogue security software program tries to make you think that your computer is infected by a virus and usually prompts you to download or buy a product that removes the virus. The names of these products frequently contain words like Antivirus, Shield, Security, Protection, or Fixer. This makes them sound legitimate. They frequently run right after you download them, or the next time that your computer starts. Rogue security software can prevent applications, such as Internet Explorer, from opening. Rogue security software might also display legitimate and important Windows files as infections.
What is ransomware?
The most devastating type of malicious software, by some counts. Definitely one of the most advanced and constantly on the rise these days. Ransomware blocks access to the data of a victim, threating to either publish it or delete it until a ransom is paid. Worse yet, there is no guarantee that paying a ransom will return access to the data, or prevent it from deletion.
This type of malware basically infects the system from the inside, locking the computer and making it useless. Simpler ransomware may lock a system that may be difficult to reverse for most people, while the more advanced variety of ransomware encrypts the files of a victim, rendering them inaccessible, and demanding a ransom payment to decrypt the files.
What is adware?
Although ad-supported software is now much more common, and known as adware in some circles, the word has been linked to malware for quite some time. While adware can refer to any program that is supported by advertising, malicious adware usually shows ads in the form of popups and windows that cannot be closed.
It is the perhaps the most lucrative and least harmful malware, designed with the specific purpose of displaying ads on your computer. Adware usage is on the rise on mobile, in particular, with some Chinese firms bundling in adware by default in certain low-cost Android smartphones.
What is keyloggers?
Software that records all the information that is typed using a keyboard. Keyloggers usually are not capable of recording information that is entered using virtual keyboards and other input devices, but physical keyboards are at risk with this type of malware. Keyloggers store the gathered information and send it to the attacker, who can then extract sensitive information like username and passwords as well as credit card details.