Spyware.


Spyware is a general term used for programs that covertly monitor your activity on your computer, gathering personal information, such as usernames, passwords, account numbers, files, and even driver’s license or social security numbers. Some spyware focuses on monitoring a person’s Internet behavior; this type of spyware often tracks the places you visit and things you do on the web, the emails you write and receive, as well as your Instant Messaging (IM) conversations. After gathering this information, the spyware then transmits that information to another computer, usually for advertising purposes.

Spyware is similar to a Trojan horse in that users unknowingly install the product when they install something else. However, while this software is almost always unwelcome, it can be used in some instances for monitoring in conjunction with an investigation and in accordance with organizational policy.

Spyware is installed in many ways:

Most often spyware is installed unknowingly with some other software that you intentionally install. For example, if you install a "free" music or file sharing service or download a screensaver, it may also install spyware. Some Web pages will attempt to install spyware when you visit their page.
A person who wants to monitor your online activities may also manually install spyware. Depending on how this is done, this might be acceptable surveillance of an individual or an unwelcome, even illegal, invasion of privacy.


Malware

Malware is a category of malicious code that includes viruses, worms, and Trojan horses. Destructive malware will utilize popular communication tools to spread, including worms sent through email and instant messages, Trojan horses dropped from web sites, and virus-infected files downloaded from peer-to-peer connections. Malware will also seek to exploit existing vulnerabilities on systems making their entry quiet and easy.

Phishing

Phishing is essentially an online con game and phishers are nothing more than tech-savvy con artists and identify thieves. They use SPAM, malicious Web sites, email messages and instant messages to trick people into divulging sensitive information, such as bank and credit card accounts.


Bots
What's a Bot?
“Bot” is actually short for robot – not the kind found in science fiction movies or on the production line in a manufacturing business. Bots are one of the most sophisticated types of crimeware facing the Internet today. Bots are similar to worms and Trojans, but earn their unique name by performing a wide variety of automated tasks on behalf of their master (the cybercriminals) who are often safely located somewhere far across the Internet. Tasks that bots can perform run the gamut from sending spam to blasting Web sites off the Internet as part of a coordinated “denial-of-service” attack. Since a bot infected computer does the bidding of its master, many people refer to these victim machines as “zombies.”

Bots sneak onto a person’s computer in many ways. Bots oftentimes spread themselves across the Internet by searching for vulnerable, unprotected computers to infect. When they find an exposed computer, they quickly infect the machine and then report back to their master. Their goal is then to stay hidden until they are awoken by their master to perform a task. Bots are so quiet that sometimes the victims first learn of them when their Internet Service Provider tells them that their computer has been spamming other Internet users. Sometimes a bot will even clean up the infected machine to make sure it does not get bumped off of the victim’s computer by another cybercriminal’s bot. Other ways in which a bot infects a machine include being downloaded by a Trojan, installed by a malicious Web site or being emailed directly to a person from an already infected machine.

Bots do not work alone, but are part of a network of infected machines called a “botnet.” Botnets are created by attackers repeatedly infecting victim computers using one or several of the techniques mentioned above. Each one of the zombie machines is controlled by a master computer called the command and control server. From the command and control server, the cybercriminals manage their botnets and instructs the army of zombie computers to work on their behalf. A botnet is typically composed of large number victim machines that stretch across the globe, from the Far East to the United States. Some botnets might have a few hundred or a couple thousand computers, but others have tens and even hundreds of thousands of zombies at their disposal.

Trojan Horse


What is a Trojan Horse?
This term "Trojan Horse" comes from a Greek fable, in which the Greeks presented a giant wooden horse to the Trojans as a peace offering. However, a nasty surprise awaited the Trojans as Greek soldiers sprung out of the hollow horse and captured Troy. Similarly, a Trojan horse program presents itself as a useful computer program, while it actually causes havoc and damage to your computer.

Increasingly, Trojans are the first stage of an attack and their primary purpose is to stay hidden while downloading and installing a stronger threat such as a bot. Unlike viruses and worms, Trojan horses cannot spread by themselves. They are often delivered to a victim through an email message where it masquerades as an image or joke, or by a malicious website, which installs the Trojan horse on a computer through vulnerabilities in web browser software such as Microsoft Internet Explorer.

After it is installed, the Trojan horse lurks silently on the infected machine, invisibly carrying out its misdeeds, such as downloading spyware, while the victim continues on with their normal activities.

 

Viruses

File viruses, also known as parasitic or executable viruses, are pieces of code that attach themselves to executable files, driver files or compressed files, and are activated when the host program is run. After activation, the virus may spread itself by attaching itself to other programs in the system, and also carry out the malevolent activity for which it was programmed. Most file viruses spread by loading themselves in system memory and looking for any other programs located on the drive. If it finds one, it modifies the program’s code so that it contains and activates the virus the next time it’s run. It keeps doing this over and over until it spreads across the system, and possibly to other systems that the infected program may be shared with. Besides spreading themselves, these viruses also carry some type of destructive constituent that can be activated immediately or by a particular ‘trigger’. The trigger could be a specific date, or the number of times the virus has been replicated, or anything equally trivial. Some examples of file viruses are Randex, Meve and MrKlunky.

 Boot sector viruses

A boot sector virus affects the boot sector of a hard disk, which is a very crucial part. The boot sector is where all information about the drive is stored, along with a program that makes it possible for the operating system to boot up. By inserting its code into the boot sector, a virus guarantees that it loads into memory during every boot sequence. A boot virus does not affect files; instead, it affects the disks that contain them. Perhaps this is the reason for their downfall. During the days when programs were carried around on floppies, the boot sector viruses used to spread like wildfire. However, with the CD-ROM revolution, it became impossible to infect pre-written data on a CD, which eventually stopped such viruses from spreading. Though boot viruses still exist, they are rare compared to new-age malicious software. Another reason why they’re not so prevalent is that operating systems today protect the boot sector, which makes it difficult for them to thrive. Examples of boot viruses are Polyboot.B and AntiEXE.

Multipartite viruses

Multipartite viruses are a combination of boot sector viruses and file viruses. These viruses come in through infected media and reside in memory. They then move on to the boot sector of the hard drive. From there, the virus infects executable files on the hard drive and spreads across the system. There aren’t too many multipartite viruses in existence today, but in their heyday, they accounted for some major problems due to their capacity to combine different infection techniques. A well-known multipartite virus is Ywinz.

Macro viruses

Macro viruses infect files that are created using certain applications or programs that contain macros. These include Microsoft Office documents such as Word documents, Excel spreadsheets, PowerPoint presentations, Access databases and other similar application files such as Corel Draw, AmiPro etc. Since macro viruses are written in the language of the application and not in that of the operating system, they are known to be platform-independent—they can spread between Windows, Mac and any other system, so long as they are running the required application. With the ever-increasing capabilities of macro languages in applications, and the possibility of infections spreading over networks, these viruses are major threats. The first macro virus was written for Microsoft Word and was discovered back in August 1995. Today, there are thousands of macro viruses in existence—some examples are Relax, Melissa.A and Bablas.

Network viruses

This kind of virus is proficient in quickly spreading across a Local Area Network (LAN) or even over the Internet. Usually, it propagates through shared resources, such as shared drives and folders. Once it infects a new system, it searches for potential targets by searching the network for other vulnerable systems. Once a new vulnerable system is found, the network virus infects the other system, and thus spreads over the network. Some of the most notorious network viruses are Nimda and SQLSlammer.

Email Viruses

An email virus could be a form of a macro virus that spreads itself to all the contacts located in the host’s email address book. If any of the email recipients open the attachment of the infected mail, the virus spreads to the new host’s address book contacts, and then proceeds to send itself to all those contacts as well. Email viruses can infect hosts even by previewing the infected email in a mail client.


There are many ways in which a virus can infect or stay dormant on your PC. However, whether active or dormant, it is dangerous to let one loose on your system, and it should be dealt with immediately.

 

This is offered as a public service and should be used for information only.