Pair Networks Blog Security,Web Hosting Know Your MalWare: Your Field Guide to Malicious Software

Know Your MalWare: Your Field Guide to Malicious Software

Know Your MalWare: Your Field Guide to Malicious Software post thumbnail image

Help prevent malware from messing with your computer by understanding how different types work.

What is MalWare?

Malicious” + “Software” = Malware

You can think of Malware much like a human virus. Malware is an umbrella term for hostile or intrusive software that a computer can catch from an outside source.

It can then take over the computer and make it do things the user may not want it to do; such as sending spam mail, stealing sensitive information, spreading the malware to other computers, etc.

In the early age of computing, the first malware programs had a less sinister intent. Many began as pranks or experiments. In 1988 the first malware program ever distributed on the Internet was written by Robert Morris, a Cornell graduate student, in a supposed attempt to guage the size of the internet. Unfortunately for Mr.Morris his program also had the unintended side effect of slowing and eventually debilitating infected computers. This became known as the “Great” or “Morris” worm, eventually causing upwards of $10 million dollars in damages.

Today, some sources estimate that malware exceeds the number of legitimate programs available online. Microsoft for instance estimates that as many as 1 in 14 downloads may contain malware code.

Symptoms of Malware

Much like a human catching cold, a computer infected with malware will likely start showing symptoms. Because there are many types of malware, the range of performance issues which could tip off an infection is fairly wide. The most common symptoms include

  • Unusually High CPU usage
  • Alerts from Security/Anti-Virus Programs
  • Sluggish Computer/Internet Browser Speeds
  • Sudden Location Change or Deletion of Files
  • Sudden Appearance of Files or Programs
  • Outgoing Spam Messaging
  • Large Volume of Pop-Up Ads
  • Odd Computer Behavior

None of these issues singularly reveals a malware program. However, it’s likely that if popup ads appear when your internet browser is not open, your security program is issuing scary warnings, or your friends have suddenly received a flood of spam mail from your address; you most likely have a malware problem.


Know Thy Enemy

There are many variations of malware, each having its own way of disrupting a computer system. As with many things – the best offense is a good defense. Familiarizing yourself with the most common malware types and their tactics is a great way to help prevent them from interrupting your daily life.



– A phishing scam disguises itself as a legitimate website, email, or program. Ever visit a fake Facebook login page or receive a fake email from your credit card company requesting information immediately or else terrible things will happen? These scams are really ‘fishing’ for your sensitive personal and billing information.

Help protect yourself: Always check the URL for any site requesting login or sensitive information. Beware of emails asking for sensitive information and never submit this information into a form embedded in an email. Legitimate financial organizations never ask for sensitive info via email. Do not feel pressured into giving information if you are not comfortable – many phishing scams use scare tactics.



– These programs monitor your activity without your knowledge. Although this may sound fairly harmless at first, spyware can significantly slow your computer. Many spyware programs also come bundled with other malware types (see Adware), and will use the information gathered to target the user with advertisements. This type of malware is significantly harder to detect.

Help protect yourself: Spyware normally comes bundled with programs, so download programs only from websites that you fully trust. Keep your Internet Browser and Security/Anti-Virus program fully updated.



– Short for Advertising-Supported Software. It’s similar to Spyware in that it is usually bundled in with “free” programs downloaded from the internet. The developer in turn receives revenue by reporting your web surfing habits to advertisers, who in turn display targeted ads to you often through pop-up windows.

Help protect yourself: Like Spyware, Adware normally comes included with free programs downloaded from the Internet. Only download programs from legitimate websites that you fully trust. Adware can also be downloaded through a vulnerable Internet Browser. Make sure to keep your Internet Browser up-to-date.



– A bot is a simple program used to perform a small task repetitively. Some bots are used for legitimate reasons. For example, many bots are used to gather information for search engines like Google or Bing. Other bots have more malicious intent, like scanning sites to collect email addresses for spamming purposes. Why are CAPTCHA tests necessary? For protection against bots.

Help protect yourself: Implementing a CAPTCHA ( aka Completely Automated Public Turing Test to tell Computers and Humans Apart) on your site’s forums, to verify users are human, is a great first step. Google and many WordPress plugins offer CAPTCHAS free to use.



– A group of computers (sometimes known as a zombie army) infected by malware and controlled by a third party. These “zombie” computers can then be programmed to direct attacks toward a separate computer. These attacks can be to shut down a competitor’s website by overloading it with requests, known as a DDoS attack, or blasting spam.

Help protect yourself: Install antvirus and antispyware programs from a trusted source. Keep your Internet Browser up to date. Due to their popularity many malware programs are written for Internet Explorer and Windows. Switching to another Internet Browser may also lower the risk of Bot/Botnet attacks.



– A bug is not technically malware, but can affect the performance of your computer. A bug is not a piece of software, it is a mistake in the software itself. A bug can be in any program whether it’s legitimate or not. Even software developers sometimes make mistakes.

Help protect yourself: Bugs are normally resolved in the development process of a computer program. End users may help protect themselves from ‘buggy’ software by only installing programs from legitimate and trusted sources.


Ransomware –

Costly and very disruptive. A type of malware that encrypts the information on your hard drive or locks down your computer system. The program then demands payment if the user wants to regain access to their data. Ransomware is on the rise and has become a very lucrative business. Ransom demands can range anywhere from $200 to $5000.

Help protect yourself: Up-to-date Antivirus software can be an effective way to protect your computer from infection online. Regularly backup your data [link]. Your most valued information (photos, files, etc.) should be backed up on a device that is not online. Ransomware is often automatically downloaded by visiting suspicious or infected websites. Avoid clicking links or opening attachments from websites or emails you do not trust.



– Difficult to detect. A Rootkit is a malicious program that installs itself in the “root” or most basic level of your Operating System. Once installed a third party user can steal information, execute commands, or use the computer as part of a botnet.

Help protect yourself: Because this malware is embedded so deeply in a system it can be very difficult to detect and remove. Prevention can be key. For the rootkit to be installed it must be triggered by the computer’s administrator. Only download and run applications from trusted sources. There are several legitimate rootkit scanning tools available online from trusted sources like McAfee, Kaspersky, and Bitdefender.


Trojan Horse

– Commonly known as a ‘Trojan’, this type of malware is used as a vehicle to download more malware onto an infected system. Trojan programs disguise themselves as a legitimate program or file for download. Once it’s gained access to your system the program can then steal information and download more malware onto your system.

Help protect yourself: Trojans are normally downloaded by an email attachment or with files from a website. Never open email attachments from unknown senders. If a Trojan has been found on your computer it may help to disconnect your computer from the internet, run an antivirus program, and delete the files in question.



– Much like human viruses, most malware viruses are programmed to perform malicious operations on a user’s system. A virus is also capable of copying itself and spreading over to other computers through a network through human activity (running programs, opening a file, etc.)

Help protect yourself: Most Viruses spread via email attachments. The email attachment is opened releasing the virus is onto your system. Don’t open email attachments unless you are expecting them. It may help to install a trusted antivirus program onto your system and keep it updated.



– Among the most common types of malware. Similar to a Computer Virus, however Worms do not necessarily need human action to spread through a network. For instance, Worms may be embedded on to an infected website. A single worm could potentially send itself to everyone listed in a system’s email contact list and replicate even further from there. Because it can replicate itself frequently on a system a worm will usually use a significant amount of your computer’s memory.

Help protect yourself: Make sure your computer has an updated firewall and trusted AntiVirus System installed. A firewall may prevent any unsolicited incoming traffic from passing onto your computer.


About Spam

– Although a symptom of malware and not malware itself, spam is a frequent issue that should be included as well. Spam is unwanted junk mail that can clutter or even completely overtake a user’s email inbox. Spammers collect email addresses from a variety of sources such as websites, chatrooms, viruses, and other spammers. Such a large volume (by some estimates up to 80% of all email sent in the year 2010) of spam is sent out each year, preventing it can feel a bit like a game of cat and mouse.

Help prevent Spam: One way that may help to prevent your address from ending up on a spammer’s list is to prevent it from being found. Don’t give out your email address in plaintext online. A bot can quickly gather thousands of email addresses made public online. Report spam through your mail client or contact your hosting provider. Many hosting companies utilize a mix of strategies to prevent spamming for their users.



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