What is malware?
Malware is malicious software.
It is written for various reasons ranging from redirecting your browsing, social engineering (getting you to buy something by conning you) to intent to cause major destruction and/or straight out theft or blackmail.
It comes in several forms including adware, viruses, trojans, worms and ransomware.
Adware (and spyware)
This malware is not necessarily written to cause damage but to serve up additional advertising which is difficult to avoid to the point of being disruptive and to collect information from your system and report back to its source. The information can range from what websites you visit to your passwords and personal details. Just about every commercial site you visit will download a tracking cookie to find out where else you’ve been since the last time you visited. Which pop up ads you see are chosen by what you’ve clicked on in the past.
Viruses
A virus is a program which is written to infect other software by embedding a copy of itself in legitimate software. It requires the legitimate software to run before it can do anything but once it gets started (eg by opening the harmless looking attachment it is in) then it performs the task it was written for. Some can then also replicate themselves or change to avoid detection by anti-virus software.
Trojans
Trojans are types of malware that come already embedded in a program that you think you need and so purposefully download it. Many of the flashing ads for various things on websites (even for antivirus software!) lead you to download useful looking programs which actually contain programs which might spy on you, steal sensitive data, open backdoors to your system to allow further penetration etc.
Worms
Worms are like viruses but they don’t spread by infecting other programs, they keep replicating themselves till they jam up your system or cause your PC to restart or shutdown completely. They don’t need to be attached to anything to get in, they can penetrate via your network or straight from the internet.
Ransomware
Ransomware usually comes in the form of an email which convinces you to click a link that is actually the malware program. The most common type at the moment encrypts your files (documents, music, pictures etc) with unbreakable encryption and instructs you to pay a sum of money (usually in the form of bitcoin) for the key to decrypt your files. There is no guarantee they will actually send you the key once you’ve paid. The only real protection against ransomware is to have a full, current backup of all your important files.
Conclusion
All of these programs in varying degrees take away system resources from the tasks you actually want your computer to be performing so it is in your interest to stop them getting in in the first place.
Be careful what you download, what attachments you open, what you click on in websites. Illegal peer to peer file sharing (torrents etc) is riddled with Trojans and malware. If you don’t know what something is, before you open it or click on it, ask someone you trust or email me using the link on this page.
Lastly, make sure that Windows and your antivirus software is always up to date.