So now let's look at different types of malware that is malicious software that you might come across.
So what does malicious software actually do?
It might delete or damage your files.
It might copy your data, your documents and files, and so on
off the network. So, for example, the Militias program could set up a connection to some external server on the Internet and start copying all your files to it.
It could change your browser. Home page will search engine.
It could spy on your activities,
including monitoring everything that you're typing.
So say when you log on
to the network or any particular resource on the network, or when you log on to websites, it can be monitoring and capturing the keys you're pressing when you're entering your passwords.
It could just be popping up advertisements. So very often something called spyware,
which monitors your activities,
is doing it in order to
pop up advertisements to try and sell you stuff.
It could make your computer part of a but Net.
A botnet is a collection of computers
that are designed to attack another system.
So what happens is your computer's compromised in some way with a little militias program on it, and so are thousands of other computers.
And that militias program just sits there doing nothing, waiting for an incoming command.
And when the attacker is ready,
he or she sends a message to all of those but nets and gets them to simultaneously launch an attack against some third party.
So how do computers get infected?
Well, one primary way is visiting unsavory websites,
so these might be websites that are promising you illegal stuff, like
Pirated software or Pirated movies and so on,
um, downloading files from the Internet.
So these days, many of us are very comfortable going to find files on the Internet and downloading them to our computer.
Now those files you download could be malicious software.
If you have a good anti malware program running,
then it will spot that and prevent the download.
You could click links in unsolicited e mails. So
There's an interesting message in There may be some kind of offer, and there's a link
you click on the link.
Just clicking on that link could download the militias program. In fact, even just opening up the unsolicited email could start downloading a malicious program to your machine,
inserting removable media
so militias software could be delivered on a CD, a DVD or a USB flash drive.
Um, so you know your colleague gives you a DVD, so hey, there's a great game on here.
You put that into your drive on as soon as you start to run it,
The malicious software is copied to your hard disk.
Same with the USB flash drive. In fact, with a USB flash drive
what the malicious attacking could do it? Just leave it lying around
so you come to your desk. You find this USB flash drive. You insert it in your computer to see what's in it, and the moment you do that, the malicious software is copied onto your hard disk,
participating in peer to peer networks like Victoria,
these are often used to find Pirated software
or Pirated movies or music on the Internet.
So although viruses often used as a collective term for malicious software, you'll notice that I've been calling it malware
malicious software is much broader than just viruses. Viruses are just one type of malware.
What is specific about a virus is that it attach is itself to in execute a ble,
so it's some malicious code that gets inserted into the executed will say word dot t x C. That's the execute herbal that runs Microsoft Word,
which means that every time you you run that application, when it's open and you're working inward,
the virus is active,
and one of the things that's going to try and do is to infect other, execute a bles on your computer.
Now that's slightly different from another type of militia software known as a worm.
A worm. It's a standalone program,
and what's specific about it is that once it infects your machine, it start scanning your network to look for other vulnerable
devices that it can attack on the network So it spreads itself around your network.
Trojans, while the term Trojan horse refers to a story in Greek mythology in which the Greeks had failed to capture the city of Troy despite a 10 year long siege of the city.
So the Greeks hit soldiers inside a large wooden horse that was left at the gates of the independent city of Troy.
The Greeks then appeared to sail away,
the inhabitants of Troy pulled the horse inside the city as a trophy of their apparent victory.
Unknown to them, however, Greek soldiers were hidden inside the horse.
At night, the Greek soldiers crept out of the horse and open the city gates to let in the rest of the Army.
So what does this have to do with malicious software?
While the analogy is used because there is a class of malicious software that tricks users into downloading it to their computers because it appears to be useful.
For example, let's say you realize that there's lots of duplicate files all over your hard disk,
and you'd like to have a quick way of finding all the duplicate files and deleting them and saving disk space.
So you go searching on the Internet and you find some little utility that says that it'll that's exactly what it will do.
Now, at that point, I mean, this might just be a malicious program that's been downloaded to a machine,
or it may actually do what it says it's going to do. But in addition to that, there's malicious code in there,
so that's a Trojan. It's a malicious program disguised as something useful that you've made download.
And then there's spyware and adware.
Now the first point to note about this is spyware, and adware is not necessarily militias.
Spyware. It's certainly spying on what you do,
but might only be. Two. Target you with advertisements rather than have any other nefarious intent.
and it may result in strange things happening, like advertisements follow you from one website to another. You might have had this experience. At some point you go shopping for something, maybe say it Amazon.
And then you open up your Facebook page and sitting right there on the right hand side are advertisements for the very products that you were looking for.
So what's been going on there is They've been spying on you,
and based on that, they're serving up advertisements,
on the other hand, by where could be malicious.
So some spyware might, for example, log the keys you press. So as you log on to different websites and into your passwords and so on, it's capturing all that information and then standing it up to whoever controls that malicious software.
ransom ways, particularly pernicious
what it does. Once it gets into your system is it starts encrypting all your files,
and it could very rapidly encrypt thousands of files.
And then a message pops up on your screen demanding a ransom.
If you pay the ransom, they'll send you a decryption key so you can un encrypt all your stuff
on because they don't want to be traceable. The ransom has often demanded in Bitcoins.
Now, usually, if you do pay the ransom, you will get the decryption key
because obviously, if they weren't giving that away, that would soon get around and people will stop paying the ransom.
So, yes, you could pay the ransom and you could get the decryption key and then decrypt all your files.
The other way you could recover from that type of attack is if you have bean meticulously doing backups,
because that way you can always restore your files from backups rather than paying ransom